MXPA00001372A - Coloured interference pigment - Google Patents

Abstract

Colored interference pigments (CIP) consisting of a flake-like layer as substrate, with a coating of metal oxide layer(s) and optionally another layer, in which at least two of the layers contain or consist of coloring agent. Independent claims are also included for (a) a process for the production of CIP with coloring agent(s) in the substrate and in the coating, by (1) dispersing or dissolving a colorant in a precursor of the substrate material, (2) spreading the dispersion as a thin film on a continuous belt, (3) drying the film, (4) removing the resulting layer from the smooth surface and optionally treating with acid and then (5) washing the resulting substrate particles and coating with layer(s) of metal oxide by precipitating the oxide from a dispersion or solution of colorant;(b) a process for the production of CIP with another colored layer on the coating, involving stages 1-4 as above followed by (5) washing the substrate particles and coating with layer(s) of metal oxide and (6) applying a layer of coloring agent to the coating;(c) a process as described in (b) for the production of CIP with colorant(s) in the substrate and a layer of colorant on the coating;(d) a process for the production of CIP with colorant(s) in the coating, by spreading a substrate precursor on a continuous belt, processing the thin film obtained and the substrate particles as in stages (2)-(5) in process (a) and then applying a layer of colorant to the coating;(e) paint, printing ink, plastics, cosmetics, ceramics and glass pigmented with CIP.

Description

PIGMENT OF INTERFERENCE, COLOR FIELD OF THE INVENTION The present invention relates to interference, color pigments, comprising absorption pigments in the carrier material and in the coating.

BACKGROUND OF THE INVENTION Inference pigments comprising absorption pigments, either in the substrate or in the coating, are known. EP 0 608 388 describes flakes of SiO_ comprising soluble dyes or «insolubies, and which are produced on a continuous band. The insoluble dyes used are pigments having a particle size of less than 1 μm and pigments refers to white, black, colored pigments or fluorescent pigments. The pigments are dispersed in the precursor of the Si02 matrix, for example in a solution of sodium liquid glass, and the dispersion is applied to a continuous band. The REF .: 32366 soluble dyes, which may be present in the Si02 matrix are chromophoric metal oxides or soluble organic pigments. In this case, the solutions of these dyes are added to the precursor before application to the web. The Si02 flakes are produced in this way and are used as substrates for the interference pigments. Interference pigments comprising carbon black as absorption pigment in the metal oxide coating are known from EP 0 499 864. These are prepared by mixing a dispersion of the substrate and a carbon black dispersion, dosing it to the aqueous solution of a metal salt, and precipitating a layer of metal oxide on the substrate, in which course the carbon black is entrained and embedded in the metal oxide layer. The pigment is subsequently calcined from 700 ° C to 900 ° C in the absence of oxygen. Interference pigments covered by a thin layer of an organic dye are known from U.S. Patent 5,156,678. These are prepared by preparing a suspension of the pigment in a solution of the dye and mixing the resulting suspension with a solvent in which the dye is insoluble. With pigments in the form of lamellae, it is often difficult to achieve a covering and polishing power, simultaneously, to a satisfactory degree. For example, Si02 flakes or mica flakes coated, for example, with one or more thin layers of metal oxide, are distinguished by interference colors and a high gloss but also at the same time, as a result of the transparent substrate, by a high transparency and hence by a comparatively low covering power. Therefore, there is a need to improve the covering power. In the case of the pigments which, in addition to the metal oxide layer, which is responsible for the generation of the interference color, comprise only an absorption pigment, the optical effects such as sordid colors, for example, are limited.

Therefore, there is a need to expand the optical effects of these pigments.

DESCRIPTION OF THE INVENTION An object of the present invention is to provide an interference pigment which possesses not only a high covering power but also comparatively greater optical effects. This object is achieved according to the invention by means of an interference pigment consisting of a layer in the form of a lamella as a substrate and a coating of at least one layer of metal oxide with or without another layer, at least two layers which comprise or consist of colorants. This object is additionally achieved according to the invention by a process for preparing the pigment of the invention, in which: a dye is dispersed or dissolved in a precursor of the substrate material, the dispersion is applied as a thin film to a continuous band - the liquid film is solidified by drying, - the resulting layer is separated from the band and, if desired, treated with an acid, the resulting particles of the substrate are washed, then coated with one or more layers of metal oxides, the precipitation of the metal oxides is carried out in a dispersion or solution of a dye. The invention further provides the use of the pigments of the invention for pigment paints, printing dyes, plastics, cosmetics and varnishes for ceramics and glasses. For this purpose they can also be used as mixtures with trademark pigments, some examples being organic and inorganic absorption pigments, metallic effect pigments and LCP pigments. In a first embodiment, the pigment of the invention consists of a substrate in the form of lamellae (1) and a coating (2) of at least one layer of metal oxide, the pigment in the substrate (1) and in the coating (2). ) comprises at least one dye (3). The structure of this pigment is shown in Figure 1. In a second embodiment, the pigment of the invention consists of a substrate in the form of lamellae (1), a coating (2) of at least one layer of metal oxide, and a dye layer (4), the pigment in the substrate (1) and in the coating (2) comprises at least one dye (3). The structure of this pigment is shown in Figure 2. In a third embodiment, the pigment of the invention consists of a substrate in the form of lamellae (1), a coating (2) of at least one layer of metal oxide, and a layer of dye (4) on the coating (2), the substrate comprises at least one dye (3). The structure of this pigment is shown in Figure 3. In a fourth embodiment, the pigment of the invention consists of a substrate in the form of lamellae (1), a coating (2) of at least one layer of metal oxide and a dye layer (4) on the coating (2), the pigment in the coating (2) comprises at least one dye (3). The structure of this pigment is shown in Figure 4. In the case of embodiments 2 to 4 of the pigment according to the invention, the substrate can be repeatedly laminated with the two-layer system consisting of the coating (2) and the dye layer (4). However, a laminate of a coating (2) and a coloring layer (4) is preferred. The pigments of the invention are based on sheet-like substrates. These substrates may consist of silica, silicates, boron oxide, borates, alumina or other transparent materials, stable materials capable of being able to adapt to soluble and insoluble dyes. The precursors used for the preparation of the substrates are solutions of organic or inorganic compounds of the metals aluminum, silicon, potassium or sodium, with borates, aluminates, fat polyols, phosphonates, silicates and mixtures thereof. A preferred precursor is liquid glass.

In the case of the mode 4 of the pigment of the invention, the substrate may also consist of mica, synthetic mica, other phyllosilicates or glass flakes. The particles of the substrate in the form of lamellae have a thickness between 0.05 and 5 μm and in particular between 0.2 and 2 μm. The extension in the other two dimensions is between 1 and 250 μm and in particular between 2 and 100 μm. In accordance with embodiments 1 to 3 of the inventive pigment, the pigment particles whose dimensions are markedly smaller than the thickness of the substrate, are incorporated as insoluble dyes within the substrate. The particle size of the trademark pigments must therefore be adapted to the desired layer thickness of the substrate. The term pigment particles should be interpreted here broadly and encompasses white, black, colored or fluorescent pigments. Suitable inorganic pigments are white pigments such as titanium dioxide, barium sulfate or zinc oxide, examples being titanium dioxide 2310 (manufacturer: Kronos), titanium dioxide R-D (manufacturer: Bayer) and titanium dioxide R-506 (manufacturer: Sachtleben). The appropriate black pigments are magnetite or pigment grade black pigment, an example being Farbruß FW 200 (Degussa). Suitable color pigments are iron oxide or chromium oxide, mixed phase oxides such as (Ti, Cr, Sb) 02 / CoAl204 (Thernard blue), ZnAl204 (Rinman's Green), (Fe, Cr) 203 and also sulfides, for example CdS. Also suitable are inorganic fluorescent pigments, such as zinc oxide loaded with silver, fluorescent, zinc sulphide loaded with copper, phosphorescent, or ultramarine color pigments. Suitable organic pigments are azo pigments, anti-aquinone pigments, indigo or thioindigo derivatives, diketopyrrolopyrol pigments 1, perylene pigments and phthalocyanine pigments. Particularly suitable red pigments are the Paliogen Marón L3920 (manufacturer: BASF), Red BO DPP-Irgazine (manufacturer: Ciba), Magenta Chinquaisia RT355D (manufacturer: Ciba), Red Hostaperm E2B70 (manufacturer: Hoechs t-Clar i ant), Red Sicotrans L2817 (manufacturer: BASF), Red Carmine, Thioindigo, Red DC 6, also known as Lithol Rubine 13 and also Red DC 33, also known as Acid Fuchsine. Particularly suitable blue pigments are Blue Hostaperm AFL (manufacturer: Hoechs tC 1 ar i ant), Blue Irgazine A3RN (manufacturer: Ciba), Blue Paliogen L6470 (manufacturer: BAS F), Blue Prussia and Blue FDC 1 also known as Blue Sparkly. The particularly suitable green pigments are the Green Monastral 64 Special (manufacturer: Zeneca-ICI), Green Hostaperm 8G (manufacturer: Hoechst-Clariant) and Green DC 5 also known as Green Alizarin Cyanine F, and yellow pigments particularly suitable are Yellow Irgazin 5GTL (manufacturer: Ciba), Yellow Irgacolor 2GLMA (manufacturer: Ciba), Amarillo FDC 5, also known as Tartrazine and Amarillo FDC 6 also known as Amarillo Dusk. Also, in order to improve the dispersion of the particles of the pigments in the precursor, it is advantageous in many cases to add wetting agents, an example being Hidropallat 884 (manufacturer: Henkel). Neither the type nor the amount of the wetting agent that is added is critical, although in general the proportion of the wetting agent is not more than 2% by weight based on the dispersion. The weight proportion of the pigment particles that are incorporated, based on the weight of the uncoated substrate, is between 0.5 and 40% and in particular between 5 and 25%. More details can be found in European Patent 0 608 388. Alternatively, the dye present on the substrate can be a soluble dye. The term soluble dye denotes any chromophoric metal oxide, examples being iron oxide, chromium oxide, and cobalt oxide or a soluble organic dye. Chromophoric compounds generally suitable for coloring the substrate are compounds of the metals titanium, vanadium, chromium, manganese, iron, cobalt, nickel and copper, preferably compounds of cobalt, copper, iron and chromium. These are added as soluble compounds to the substrate precursor. The result is a transparent, color substrate that has a color scale similar to that of transparent, colored glasses. Adding iron compounds, for example, results in a reddish brown hue, adding chromium compounds, green nuances, and adding cobalt compounds result in compounds that give blue shades. As soluble, organic dyes, it is possible to use alkali-soluble hydroquinone raquinone dyes or azo dyes, acids. The soluble dye is present in the uncoated substrate - in a proportion of 0.01 to 50% by weight, preferably 1 to 30% by weight. More details can be found in EP 0 608 388. The pigments of the invention also include additional colorants in the metal oxide coating. For example, if carbon black particles are used, then the particle size used is from 5 to 200 nm, and in particular from 10 to 100 nm. Pigments of this type, which preferably contain carbon black particles in layers of titanium dioxide, iron oxide, tin oxide, chromium oxide and zinc oxide, are described in EP 0 499 864. The pigments of the invention may also comprise particles of titanium dioxide, alumina, silica, tin dioxide, magnesium oxide, zinc oxide, cerium dioxide, tungsten oxide, molybdenum oxide and zirconium oxide or other mixed oxides, such as Cr2Fe0, CoAl204 or NiAl204 in the metal oxide layer. Instead of inorganic pigment particles it is also possible that organic pigment particles are present in the metal oxide layer, with thermally stable organic pigments being particularly preferred. The organic pigment particles used are preferably phthalocyanines, lacquers of basic dyes with heteropoly acids, anthraquinones, phenazines, phenoxazines, said topyrrolopyrroles or perylenes. In principle, all pigments which have been described for incorporation into the substrate can also be "incorporated into the coating of the pigment of the invention." The incorporation of small metal oxide particles or organic pigment particles having an average 10 to 40 nm within the cavities of the metal oxide coating achieves a marked increase in the hiding power and in the luster, together with great homogeneity of the coating compared with the pigments obtained by coprecipitation. In the case of colored pigment particles, the absorption color dependent on the observation angle, the pigments of the invention can be varied within a wide range due to the variation of the concentration of the pigment particles incorporated. The pigment particles incorporated, based on the matrix, is between 0.5 and 30% and in particular between 2 and 20%. More information on pigments comprising pigment particles in the coating can be found in DE 41 40 295. In the case of a dye layer on the metal oxide coating, the colorant can, in accordance with US Pat. No. 4,772,331, form the outermost layer of the pigment together with an organic binder. However, it is possible to apply phthalocyanine dyes or phthalocyanine metal dyes without the aid of binder systems or other auxiliaries, such as an external layer of firm adhesion, in accordance with U.S. patent 5,156,678. Alternatively, the dyes can be applied to the metal oxide coating by a high-speed stirring process in accordance with U.S. Pat., 336,309. The proportion of the dye forming the outer layer is from 0.5 to 30% by weight, preferably from 1 to 10% by weight, based on the total weight of the pigment. It is possible in principle to employ all dyes which are also suitable for coloring the substrate. The pigment of the invention is prepared in a two-step process. In the first stage the substrate in the form of lamellae is prepared with the aid of a continuous band.

The continuous band, which is guided on a roller system, passes through an applicator where it is covered with a thin film of the precursor. The precursor alternatively either contains organic or inorganic pigment particles in the form of a dispersion, or contains dissolved dyes or chromophoric metal compounds. The most appropriate applicators that can be used are roller applicators and also flow type applicators. The speed of the band should be between 2 and 800 m / min, preferably from 5 to 400 m / min. To achieve the uniform weight of the plastic band it is wise to add a commercially available wetting agent to the coating or dispersion solution, or to activate the surface of the band by flame treatment, corona treatment or ionization. The coated band then passes through a drying section in which the layer is dried at temperatures between 30 and 200 ° C. The dryers that can be used include, for example, commercial brand infrared dryers, circulating air jets and UV dryers. After passing through the drying section, the web is guided through stripping baths filled with water or diluted acids, in which the dried layer is removed from the web. The detachment process is supported here by additional apparatuses, such as for example nozzles, brushes or ultrasound. A subsequent dryer dries the band before the next coating operation. The web should be made of a chemical resistant polymer and heat to ensure a sufficient service life and high drying temperatures. Suitable materials for this purpose are those such as Polyethylene Terephthalate (PET) or other polyesters and polyacrylates. The width of the film is typically between a few centimeters and several meters. The thickness is between 10 μm and a few millimeters, these two parameters are optimized with respect to the particular requirements.

Further details relating to continuous web processes are known from US Pat. No. 3,138,475, EP 0 240 952 and EP 0 608 388. Aqueous solutions of thermally hydrolysable titanium compounds are used as the precursor for the preparation of lamellae. of titanium dioxide as the substrate. A preferred precursor is aqueous titanium tetrachloride in solution. The concentration is from 7 to 30% by weight, preferably from 8 to 15% by weight. The lamellae of titanium dioxide have a thickness of between 10 nm and 500 nm, preferably between 40 and 150 nm. The extension in the other two dimensions is above 200 μm and in particular between 5 and 50 ^^. The production of Ti02 flakes on a continuous web is described in DE 196 18 564. As the precursor for the production of silica flakes as a substrate, a diluted solution of liquid glass is used which adjusts to a concentration of 10 to 30% by weight. 1 The silica lamellae are between 50 and 2000 nm and in particular between 100 and 1000 nm. The extension in the other two dimensions is between 1 and 10,000 μm, and in particular between 10 and 100 μm. When the liquid glass is used as the precursor it is necessary to subject the particles of the substrate to an acid treatment followed by the separation of the strip. In a second stage of the process, without intermediate drying, the sheet-like substrate particles separated from the web are coated with more metal oxide in accordance with the known processes. If a layer of titanium dioxide is applied as a coating to the substrate, it is preferred to use the process described in U.S. Patent 3,553,001. An aqueous solution of a titanium salt is slowly added to the suspension, heated between 50 and 100 ° C, especially at a temperature of 70 to 80 ° C, of the substrate particles in the form of lamellae and of a pigment which is going to be incorporated into the titanium dioxide layer, and a substantially constant pH of about 0.5 to 5, and especially about 1.5 to 2.5, is maintained by the simultaneous dosing of a base, such as a solution of aqueous ammonia or an aqueous solution of alkali metal hydroxide. As soon as the desired thickness of the layer, of precipitated Ti02, has been achieved, the addition of the titanium salt solution is stopped. This process, which is also known as the titration process, is notable for the fact that it avoids an excess of titanium salt. This is achieved by supplying to the hydrolysis, per unit time, only the amount that is required for a uniform coating with the hydrated Ti02 and which can be accommodated per unit time by the available surface area of the particles that are coated. As a result there is no formation of hydrated titanium dioxide particles which do not deposit on the surface to be coated. The amount of titanium salt that is added per minute in this case is in the order of magnitude of about 0.01 to 20.10"5 mole of titanium salt per square meter of surface to be coated.The particles of the pigment or dye particles that they are to be incorporated into the titanium dioxide layer they can also be finely dispersed in the titanium salt solution or they can be added separately to the substrate dispersion simultaneously with the metal salt solution, in the form of an aqueous dispersion. The titanium oxide hydrate is precipitated, and the pigment particles or dye particles present in the reaction medium are entrained and incorporated into the cavities of the precipitated water-containing oxide layer. It is washed and dried, and if desired, is then calcined at temperatures between 50 and 1100 ° C, preferably between 50 and 150 ° C. Incorporation by precipitation of the pigment particles and the dye particles in the metal oxide layers is described in DE 41 40 295. Instead of titanium dioxide, the substrate can also be coated with other metal oxides. Examples of suitable metal oxides or mixtures thereof are zirconium oxide, zinc oxide, iron oxides and / or chromium oxide, especially Fe203. The coating of Si02 flakes is known from EP 0 608 388. Furthermore, the deposition of metal oxides or mixtures of metal oxides on sheet-like substrates through wet chemical means is described in the German Patents and Patent Applications. 14 67 468, 19 59 998, 20 09 566, 22 14 545, 22 15 191, 22 44 298, 23 13 331, 25 22 572, 31 37 808, 31 37 809, 31 51 343, 31 51 354, 31 51 355, 32 11 602 and 32 53 017. In a particular embodiment of the pigment of the invention, an additional dye layer is deposited as the outermost layer on the metal oxide layer. This colorant can be embedded in a binder in accordance with U.S. Patent 4,772,331. The preparation takes place by mixing a suspension or solution of the dye and an organic binder in water and / or alcohol with a suspension of the pigment in the form of lamellae in a solution of an organic binder in water and / or alcohol, the dye precipitating on the surface of the pigment in the form of lamellae and being bound by the organic binder. Alternatively, the colorant can be applied to the pigment without the need for a binder. A suspension of the pigment in a solution of the dye is mixed with a solvent in which the dye is insoluble. As a result, the colorant deposits on the pigment and forms a firmly adherent layer. This process is described in U.S. Patent 5,156,678. A further possibility is to apply the colorant to the pigment using a high speed agitation process, in which the pigment and the colorant are intensively mixed with one another in the dry state. This process is described in the US Patent 5, 336, 309. In addition, the outermost colorant layer may consist of a colored lacquer, especially an aluminum lacquer. Up to this point, a layer of aluminum hydroxide is precipitated on and in a second step, it is lacquered with a coloring lacquer. The process is described in more detail in US Patents 4, 084, 983 and 4, 323, 554. It is possible to subject the finished pigment to a subsequent coating or subsequent treatment, which increases the stability to light, the stability to the weathering and chemical stability or facilitates the handling of pigment, especially its incorporation in different media. Subsequent coatings or suitable subsequent treatments are, for example, the processes described in DE-C 22 15 191, DE-A 31 51 354, DE-A 32 35 017 or DE-A 33 34 598. The substances applied additionally they constitute only about 0.1 to 5% by weight, preferably 0.5 to 3% by weight, of the total pigment. The following examples are to illustrate the invention without restricting it. Interesting color effects can be generated. For example, if the dye layer on the metal oxide coating is blue, the interference color is golden and the color of the substrate is red, then a green is obtained with a slight deviation of the angle of incidence and a bluish silver is obtained with a greater deviation, while the tone of the mass is bluish violet. If, for example, the dye layer on the metal oxide layer is red, the interference color is golden and the color of the substrate is blue, then an orange is obtained with a slight deviation of the angle of incidence and a color is obtained reddish silver with an even greater deviation, while the tone of the mass is reddish violet. With this combination of two absorption pigments with metal oxide layers that generate the interference colors it is possible to use thermally sensitive dyes as the outermost layer, since in all these cases all that remains is to dry the pigment.

Example 1.

In a bead mill, 500 ml of a 3% dispersion of DPP BO red particles (Ciba) are prepared. To help the dispersion is added 0.5% of a dispersion additive (Hydropallat 884 from Henkel). This suspension is then mixed in a 1: 1 ratio with liquid glass. This dispersion is converted as described in PCT / EP 92/02351, with the aid of a continuous band, in Si02 flakes which contain Red DPP particles. 100 g of flakes obtained in this manner are suspended in 2 liter of water and heated to 75 ° C. A solution consisting of 10 g of, 5 H20 and 30 ml of HCl in 200 ml of water is dosed into the suspension. During the addition, the pH is kept constant with strong solution of 32% NaOH. After the end of the addition of the SnCl 4 solution, 450 ml of TiCl 4 solution (400 g of TiCl 4 / l of water) are added. During the coating, the pH is kept constant by the addition of strong solution of 32% NaOH. After the addition is complete, stirring is continued at 75 ° C for 15 minutes. The pigment is separated by filtration, washed until it is free of salt and dried at 150 ° C. 50 g of the product obtained in this manner are suspended in 1 liter of water and heated to 75 ° C. A solution of 6 g of AlCl3.6H20 in 100 ml of water is dosed to the suspension at a pH of 8, the pH is kept constant by the simultaneous addition of a strong solution of 10% NaOH. After a stirring phase of 30 minutes a pH of 4.3 is stabilized and 2 ml of Ethomeen S12 are added. Then a solution of 0.3 g of A1C13.6H20 in 100 ml of water and a solution of 1 g of Blue Acid Duasyn AE02 in 100 ml of water are dosed. During the coating, there is virtually no change in pH, which is regulated by the addition of a few drops of strong HCl at 5%. This is followed by the first addition of 50 ml of a diluted solution of sodium liquid glass (7.5 ml of sodium liquid glass diluted with 42.5 ml of water) and then 2.5 g of A1K (S04) 2 dissolved in 50 ml of water, without regulating the pH. The product is filtered off with suction, washed until it is free of salt and dried at 80 ° C.

The result is an interference pigment of a golden color which, when the angle of observation is altered, first exhibits a green color and then a bluish violet color.

Example 2 In a bead mill, 500 ml of a 3% dispersion of cobalt oxide particles are prepared. To assist the dispersion, 0.5% of a dispersing additive (Hydropallat 884 from Henkel) is added. This suspension is then mixed, in a 1: 1 ratio, with liquid glass. This dispersion is converted as described in PCT / EP 92/02351, with the aid of a continuous band, in Si02 flakes which contain blue cobalt oxide particles. 100 g of the flakes obtained in this way are suspended in 2 1 of water and heated to 75 ° C. A solution consisting of 10 g of SnCl4.5H20 and 30 ml of 37% strenHCl in 200 ml of water , the suspension is dosed. During the addition, the pH is kept constant with strong solution of 32% NaOH. After the end of the addition of the SnCl 4 solution, 450 ml of TiC 14 solution (4-00 g of T i C 14 / l of water) are dosed therein. During the coating, the pH is kept constant by the addition of a strong solution of 32% NaOH. After the addition is complete, stirring is continued at 75 ° C for 15 minutes. The pigment is separated by filtration, washed until it is free of salt and dried at 150 ° C. 50 g of the product obtained in this manner are suspended in 1 liter of water and heated to 75 ° C. A solution of 6 g of A1C13.6H20 in 100 ml of water is metered into the suspension at a pH of 8, the pH is kept constant by the simultaneous addition of a strong solution of 10% NaOH. After a stirring phase of 30 minutes a pH of 4.3 is stabilized and 2 ml of Ethomeen S12 are added. Then a solution of 0.3 g of A1C13.6H20 in 100 ml of water and a solution of 1 g of Allura Red (Red 40 FDC) in 100 ml of water is dosed. During the coating, there is virtually no change in pH, which is regulated by the addition of a few drops of strong HCl at 5%. This is followed first by the addition of 50 ml of a diluted solution of liquid sodium glass (7.5 ml of sodium liquid glass diluted with 42.5 ml of water) and then 2.5 g of A1K (S04) 2 dissolved in 50 ml of water, without regulating the pH. The product is filtered off with suction until it is free of salt and dried at 80 ° C. The result is an interference pigment of a golden color which, when the angle of observation is altered, first exhibits an orange color and then a reddish violet color.

Example 3 In a bead mill, 500 ml of a 3% strong dispersion of Red DPP BO (Ciba) particles are prepared. To aid in the dispersion, 0.5% of a dispersing additive (Hydropallat 884 from Henkel) is added. This suspension is then mixed, in a 1: 1 ratio, with liquid glass. This dispersion is converted as described in PCT / EP 92/02351, with the aid of a continuous band, into SiO flakes containing Red DPP particles. 100 g of flakes obtained in this way are suspended in 2 1 of water and heated to 75 ° C. A solution consisting of 10 g of SnCl .5H20 and 30 ml of 37% strength HCl in 200 ml of water are metered into the suspension. During the addition the pH is kept constant with a strong solution of 32% NaOH. After finishing the addition of the SnC14 solution, 450 ml of TiCl4 in solution (400 g of TiCl4 / l of water) are dosed therein. Simultaneously but separately, a suspension of 10 g of Prussian Blue in 440 ml of water is added. During the coating the pH is kept constant by the addition of a strong solution of 32% NaOH. After the addition is complete, stirring is continued at 75 ° C for 15 minutes. The pigment is separated by filtration, washed until it is free of salt and dried at 150 ° C. The result is a gold-colored interference pigment which, when the observation angle is altered, first exhibits a green color and then a bluish violet color.

Example 4 In a bead mill, 500 ml of a 3% dispersion of cobalt oxide particles are prepared. To assist the dispersion, 0.5% of a dispersant additive is added (Hydropallat 884 from Henkel). The suspension is then mixed, in a 1: 1 ratio, with liquid glass. This dispersion is converted as described in PCT / EP 92/02351, with the aid of a continuous band, in Si02 flakes which contain blue cobalt oxide particles. 100 g of flakes obtained in this way are suspended in 2 1 of water and heated to 75 ° C. A solution consisting of 10 g of SnCl4.5H20 and 30 ml of 37% strength HCl in 200 ml of water is metered into the suspension. During the addition the pH is kept constant with a strong solution of 32% NaOH. After the end of the addition of the SnCl 4 solution, 450 ml of TiCl 4 solution (400 g of TiCl 4 / l of water) are added. Simultaneously but separately, a suspension of 10 g of Red BL DPP in 430 ml of water is added. During the coating the pH is kept constant by the addition of a strong solution of 32% NaOH. After the addition is complete, stirring is continued at 75 ° C for 15 minutes. The pigment is separated by filtration, washed until it is free of salt and dried at 150 ° C. The result is a gold-colored interference pigment which, when the angle of observation is altered, first exhibits an orange color and then a reddish violet color.

Example 5 100 grams of mica (particle size 10-40 μm) are suspended in 2 1 of water and the suspension is heated to 75 ° C. A solution consisting of 10 g of SnCl4.5H20 and 30 ml of 37% strength HCl in 200 ml of water are metered into the suspension. During the addition the pH is kept constant with a strong solution of 32% NaOH. After finishing the addition of the SnCl4 solution, 450 ml of TiCl4 / l water solution are dosed). Simultaneously but separately, a suspension of 10 g of Prussian Blue in 440 ml of water is added.

During the coating the pH is kept constant by the addition of a strong solution of 32% NaOH. After the addition is complete, stirring is continued at 75 ° C for 15 minutes. The pigment is separated by filtration, washed until it is free to salt and dried at 150 ° C. 50 g of the product obtained in this manner are suspended in 1 liter of water and heated to 75 ° C. A solution of 6 g of A1C13.6H20 in 100 ml of water is dosed into the suspension at a pH of 8, the pH is kept constant by the simultaneous addition of a strong 10% solution of NaOH. After a stirring phase for 30 minutes a pH of 4.3 is established and 2 ml of Ethomeen S12 are added. Then a solution of 0.3 g of A1C13.6H20 in 100 ml of water and a solution of 1 g of Arulla Red (Red 40 FDC) in 100 ml of water is dosed. During the coating, there is virtually no change in pH which is regulated by the addition of a few drops of strong HCl at 5%. This is followed first by the addition of 50 ml of a diluted solution of sodium liquid glass (7.5 ml of sodium liquid glass diluted with 42.5 ml of water) and then 2.5 g of A1K (S04) 2 dissolved in 50 ml of water, without regulating the pH. The product is filtered off with suction, until it is free of salt and dried at 80 ° C. The result is a gold-colored interference pigment which, when the angle of observation is altered, first exhibits an orange color and then a reddish violet color. It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention. Having described the invention as above, property is claimed as contained in the following:

Claims (15)

1. The interference pigment, color, characterized in that it consists of a layer in the form of lamellae, as a substrate, and a coating of at least one layer of metal oxide with or without an additional layer, at least two layers comprising or consisting of dyes

2. The interference pigment, color, according to the indication 1 characterized in that it consists of a substrate in the form of lamellae and a coating of at least one layer of metal oxide, the pigment in the substrate and the coating comprises at least a dye

3. The interference pigment according to claim 1, characterized in that it consists of a substrate in the form of lamellae, a coating of at least one layer of metal oxide, and a layer of colorant on the coating, the pigment on the substrate and in the coating it comprises at least one colorant.

4. The interference pigment according to claim 1, characterized in that it consists of a substrate in the form of lamellae, a coating of at least one layer of metal oxide, and a layer of dye on the coating, the pigment in the substrate comprises at least one colorant.

5. The interference pigment according to claim 1, characterized in that it consists of a substrate in the form of lamellae, of coating of at least one layer of metal oxide, and of a layer of colorant on the coating, the pigment in the coating comprises at least one colorant.

6. The interference pigment according to at least one of the rei indications from 1 to 5, characterized in that the substrate in the form of lamellae is produced from a precursor, on a continuous band.

7. The interference pigment according to claim 6, characterized in that the precursor is a metal compound, soluble in water, which can be hydrolyzed thermally or consists of aqueous solutions of organic or inorganic compounds of the metals aluminum, silicon, potassium or sodium with borates, aluminates, pol i fo s fat os, met a fos fos t os, silicates or mixtures of these.

8. The interference pigment according to at least one of claims 1 to 7, characterized in that the metal oxide layer consists of titanium dioxide, zirconium oxide, zinc oxide, iron oxides, chromium oxide, tin oxide loaded with antimony and mixtures of the same.

9. The interference pigment according to at least one of claims 1 to 8, characterized in that the dye is an inorganic pigment, a soluble organic dye or a chromophoric metal oxide.

10. The process for preparing the pigment according to claim 2, characterized in that a dye is dispersed or dissolved in a precursor of the substrate material, the dispersion is applied as a thin film to a continuous web, the liquid film is solidified by drying, the resulting layer is separated from the smooth surface and, if desired, treated with an acid, the resulting substrate particles are washed and then coated with one or more layers of metal oxides, the precipitation of the oxides Metals takes place from a dispersion or solution of a dye.

11. The process for the preparation of the pigment according to claim 3, characterized in that a dye is dispersed or dissolved in a precursor of the substrate material, the dispersion is applied as a thin film to a continuous web, the liquid film is solidified by drying, the resulting layer is separated from the smooth surface and, if desired, treated with acid, the resulting substrate particles are washed and then coated with one or more layers of metal oxides, a layer of dye It is applied to the coating.

12. The process for preparing the pigment according to claim 4, characterized in that a dye is dispersed or dissolved in a precursor of the substrate material, the dispersion is applied as a thin film to a continuous web, the liquid film is solidified by drying, - the resulting layer is separated from the smooth surface and, if desired, treated with an acid, the resultant resultant substrate particles are washed and then coated with one or more layers of metal oxides and a dye layer is applied to the coating.

13. The process for the preparation of the pigment according to claim 5, characterized in that a precursor of the substrate material is applied as a thin film to a continuous web, the liquid film is solidified by drying, the resulting layer is separated from the smooth surface and, if desired, treated with an acid, the resulting particles of the substrate are washed and then coated with one or more layers of metal oxides, the precipitation of the metal oxides takes place from a dispersion or solution of a dye and a dye layer is applied to the coating.

14. The use of the pigment according to claims 1 to 9 for pigmenting paints, printing inks, plastics, cosmetics and varnishes for ceramics and glass s.

15. Paints, printing inks, plastics, cosmetics, ceramics and varnishes, characterized because they are pigmented with a pigment in accordance with the rei indications from 1 to 9.