DE19802234A1 - Goniochromatic lustre multi-coated pigment used for pigmenting lacquers, printing inks, inks, etc. - Google Patents

Abstract

Goniochromatic lustre pigments, based on multi-coated flaky substrates, have a zirconium (Zr) oxide layer (I) containing carboxylate as low-refracting layer. Also claimed is a method of coating a pigment substrate. The low refracting layer is produced by hydrolytic decomposition of a Zr alkoxy-carboxylate of formula (R-COO)Zr(OR<1>)3 (2) in the presence of the substrate particles and an organic solvent for (2), where R<1> = 2-6 C alkyl.

Description

The present invention relates to new goniochromatic sheen pigments based on multi-coated flaky Substrates that as a carboxylate zirconium oxide layer low refractive index layer included.

The invention further relates to the use of the goniochroma tables glossy pigments for coloring paints, printing inks, tin plastic, glass, ceramic products and accessories preparations of decorative cosmetics.

The invention also relates to a method for coating of pigmentary substrates with a carboxylate-containing zirco nium oxide layer.

Gloss or effect pigments are used in many areas of technology used, for example in automotive paints, in the decorative Coating, plastic coloring, in painting, printing, especially security printing inks as well as in cosmetics.

Their optical effect is based on the directed reflection of Light on predominantly flat, parallel to each other aligned, metallic or highly refractive pigment particles. Depending on the composition of the pigment platelets Interference, reflection and absorption phenomena depend on the angle Color and brightness impressions.

Because of their non-copiable optical effects, these gain Pigments of increasing importance for the production of counterfeit secure securities such as bank notes, checks, credit cards, Credit cards, tax stamps, stamps, train and plane tickets, Phonecards, lottery tickets, gift certificates, ID cards and Identification cards.

Labels made with the effect pigments and the lack of these labels or their changes, at for example in a color copy (disappearance of color flops and Gloss effects) are safe with the naked eye recognizable and thus make it easy to distinguish the origi nals from the copy.  

Of particular interest are goniochromatic gloss pigments, which an angle-dependent color change between several intensi Show interference colors and by covering metallic or highly refractive non-metallic, transparent to semi-transparent renter, platelet-shaped substrates with a combination of low refractive and high refractive, reflective, for vision obtainable light at least partially transparent layers are.

For example, in US-A-3,438,796 and 5,135,812 metallic sheen described pigments that have a central opaque aluminum film have alternating on both sides with dielectric, low breaking films (silicon dioxide, magnesium fluoride) and transparent metal films (aluminum, chrome) is coated. Because of their very complex production (alternating Evaporating a substrate film in a high vacuum with the difference Lichen film materials, removing the film from the evaporated multilayer film and its crushing on pigment particle size) is the central metal film of these pigments only coated on the top and bottom of the plate.

From EP-A-668 329, DE-A-195 16 181, 195 15 988 and 44 37 753 goniochromatic luster pigments are known which do not have the disadvantages mentioned above and by coating metal platelets (in particular aluminum platelets) via CVD processes (chemical vapor deposition) or wet-chemical with SiO ₂ as a low-refractive metal oxide layer and non-selectively from sorbing, metals, metal oxides and / or metal sulfides containing layers.

Furthermore, DE-A-195 25 503 describes non-metallic gonio-chromatic luster pigments based on mica platelets coated with highly refractive metal oxides or platelet-shaped iron oxide as preferred substrates, which also if with SiO ₂ as a low-refractive layer and with metals such as molybdenum, metal sulfides such as Molybdenum sulfide or metal oxides such as iron oxide are coated as a reflective layer which is at least partially transparent to visible light.

Zirconium dioxide is known as a high-index metal oxide for coating mica pigments and glass flakes. The ZrO ₂ layer is applied to the substrate particles by acid hydrolysis of inorganic zirconium salts or by hydrolysis of zirconium alkoxides with water in the presence of butanol and subsequent calcination to dry the water-containing oxide layer (US Pat. Nos. 3,087,828 and 3,437,515 and JP-A-116 508/1994).

JP-A-280 817/1992 describes zirconium propoxide in the presence of Acetic acid and water hydrolyzed to a large area with a glass To coat zirconia film.

Carboxylate-containing zirconium oxide is not a material for the Known coating of pigments. According to Chemical Materials, 7, 1117-1123 (1995) zirconium oxide acetate films are suitable position of chemical sensors, while zirconium complexes of Carboxylic acids in DE-A-195 23 539 as corrosion inhibitors be used.

The object of the invention was to find a material which is a low refractive index, interference-capable film on Pig ment substrates can be applied, and thus more goniochromati provide glossy pigments that are characterized by advantageous Characterize application properties and in an economical manner can be produced.

Accordingly, goniochromatic gloss pigments based on stratified platelet-shaped substrates found that a carb zirconium oxide layer containing oxylate as low refractive index layer contain.

In addition, the use of these pigments for coloring Varnishes, printing inks, inks, plastics, glasses, ceramic Products and preparations of decorative cosmetics found.

Last but not least, there was a method of coating a pigmen tär substrate with a carboxylate-containing zirconium oxide layer found, which is characterized in that a zirco niumalkoxycarboxylate in the presence of the substrate particles and one organic solvent in which the zirconium alkoxy carboxylate is soluble, hydrolytically decomposes.

The carboxylate contained in the zirconium oxide layer preferably has the general formula I.

R-COO ^⊖ I

in which R is phenyl or naphthyl, which can in each case be substituted by C ₁ -C ₄ -alkyl or -alkoxy, denotes C ₁ -C ₉ -alkyl or hydrogen.

Suitable alkyl and alkoxy radicals can be branched and unbranched be, the alkyl radicals of the aliphatic carboxylic acids are preferably unbranched. In particular, for. B. called: Methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, Pentyl, isopentyl, neopentyl, tert-pentyl, hexyl, 2-methyl pentyl, heptyl, 1-ethylpentyl, octyl, 2-ethylhexyl, isooctyl, Nonyl and isononyl, the terms isooctyl and isononyl Trivial names are and of those after oxosynthesis alcohols obtained) and methoxy, ethoxy, propoxy, Isopropoxy, butoxy, isobutoxy and tert-butoxy.

Examples of substituted aryl radicals are, for example p-methylphenyl, p-ethylphenyl, p-methoxyphenyl and p-ethoxyphenyl to call.

Examples of suitable carboxylates are aliphatic carboxylates such as formate, acetate, propionate and butyrate and especially aromati cal carboxylates such as benzoate, p-methylbenzoate, p-methoxybenzoate and naphthoate, where p-methylbenzoate, p-methoxybenzoate and ins special benzoate are preferred.

In the luster pigments according to the invention, the mole is ratio of carboxylate to zirconium usually 0.5 to 1.5: 1, preferably 0.8 to 1.2: 1 and particularly preferably about 1: 1.

For the preferred benzoate-containing zirconium oxide layers, an approximate composition of [ZrO (OH) C ₆ H ₅ COO] _n or [Zr ₂ O ₃ (C ₆ H ₅ COO) ₂ ] _n can be given.

The carboxylate-containing zirconium oxide layer according to the invention is distinguished by its low refractive index of approximately 1.7-1.8 and its low density of 1.8-1.9 g / cm ³ . Zirconium dioxide, on the other hand, has a density of 6.3 g / cm ³ (cubic ZrO ₂ ) or 5.6 g / cm ³ (monoclinic baddeleyite) and a refractive index of 2.1 to 2.2.

In addition, the carboxylate-containing zirconium oxide layer according to the invention is particularly distinguished by its uniform, homogeneous, film-like structure and thus its ability to interfere and its smooth surface, and is therefore advantageous for replacing the low-refractive index SiO ₂ layers due to their greater density contribute significantly more to the total weight of the pigment and thus reduce the hiding power of metal pigments.

Depending on the particle size and the specific surface of the used substrate particles contain the invention Luster pigments generally contain 10 to 75% by weight of carboxylate Zirconium oxide, based on that with the zirconium oxide layer put pigment, which is generally a zirconia layer thickness from 20 to 500 nm.

In the preferred goniochromatic gloss pigments according to the invention, the substrate particles have at least one layer package

• A) the carboxylate-containing zirconium oxide layer and
• B) a reflective layer that allows for visible light is at least partially permeable,

as well as additional if desired

• C) an outer protective layer

on.

Under "is at least partially transparent to visible light" to understand that generally at least 10% is preferred at least 30% of the incident light is transmitted.

The preferred gloss pigments according to the invention thus contain the colorless, low-index carboxylate-containing zirconium oxide layer (A) in combination with a reflective, for sight bare light at least partially transparent coating (B), which are non-selective or selectively absorbent or colorless can. You can have multiple, same or different combinations (Layer packets) (A) + (B), but the Bele is preferred with only one shift package (A) + (B). In addition, can an outer layer to protect the underlying layer (B) Layer (C) can be applied.

The thickness of the carboxylate-containing zirconium oxide coating (A) as already mentioned, generally carries out 20 to 500 nm before moves 100 to 400 nm. Since the layer (A) essentially the Interference colors of the pigments of the invention determined they show for a particularly distinctive play of colors and therefore also particularly preferred gloss pigments that only have one layer package (A) + (B) have a minimum layer thickness of about 170 nm. If there are several (e.g. 2, 3 or 4) layer packages (A) + (B)  then the layer thickness of (A) is preferably 20 to 200 nm.

Both are highly suitable for the reflective coating (B) refractive, selective or non-selective absorbing or color loose substances as well as low refractive index, but a high absorption constant, non-selectively absorbing substance zen, which of course also film-like and permanent must be separable.

As high refractive index materials suitable for layer (B) e.g. B. non-selectively absorbing materials such as metals, metal oxides, metal sulfides and their mixtures, which also selectively sorbing metal oxides may contain a minor amount NEN, and selectively absorbent or colorless materials such as to name in particular metal oxides, which as a rule each have a refractive index n of ≧ 2.0, preferably ≧ 2.4.

The following may be mentioned in particular as non-selectively absorbing high-index materials suitable for the layer (B):

• - Metals caused by volatile metal decomposition connections can be applied, especially before increases molybdenum, preferably iron, tungsten and chrome, too Cobalt and nickel, and mixtures of these metals; Metals that are wet chemical by reduction from metal salt solutions such as silver, copper, Gold, palladium and platinum as well as cobalt and nickel and Alloys such as NiP, NiB, NiCo, NiWP, CoP and AgAu;
• - Metal oxides such as preferably magnetite Fe ₃ O ₄ , cobalt oxide (CoO, Co ₃ O ₄ ) and vanadium oxide (VO ₂ , V ₂ O ₃ ) as well as mixtures of these oxides with the metals, such as in particular magnetite and eggs;
• - Metal sulfides such as particularly preferred molybdenum sulfide, preferably iron sulfide, tungsten sulfide and chromium sulfide, also cobalt sulfide and nickel sulfide and mixtures of these sulfides such as MoS ₂ / WS ₂ and especially also mixtures of these sulfides with the respective metal, such as in particular MoS ₂ and molybdenum, and Ge mix with oxides of the respective metal, such as MoS ₂ and molybdenum oxides.

Suitable as a non-selectively absorbing high-index layer (B) z. B. also layers of colorless high-index materials such as Zirconium dioxide and especially titanium dioxide, in which not  selectively absorbing (black) material (e.g. carbon) installed or which are coated with this material (EP-A-499 864).

Examples of selectively absorbing high-index layer materials (B) are, in particular, colored oxides such as, preferably, iron (III) oxide (α- and γ-Fe ₂ O ₃ , red), chromium (III) oxide (green) and also vanadium pentoxide (orange) ) and colored nitrides such as titanium nitride (TiN, blue).

Examples of suitable colorless high-index layer materials (B) are especially metal oxides such as zirconium dioxide and above all Titanium dioxide.

Finally, are suitable as low refractive index, non-selective sorbent materials with high absorption constants for the Layer (B) especially metals such as aluminum.

Because the layer (B) is not opaque, but for visible light should be at least partially permeable (semi-transparent) they depend on the optical properties of the chose layer materials of different thickness.

For example, their layer thickness for non-selectively absorbing high-index materials such as metals, black metal oxides and sulfides is generally 1 to 100 nm, layer thicknesses of approximately 1 to 25 nm for highly absorbent metals such as molybdenum and chromium, layer thicknesses of approximately for weakly absorbing materials such as magnetite 10 to 50 nm and for metal sulfide-containing materials such as MoS ₂ -containing layers, layer thicknesses of 5 to 20 nm are preferred.

For colored high-index metal oxide layers (B), this is Layer thickness usually 1 to 500 nm, preferably 10 to 150 nm.

Low-refractive but highly absorbent aluminum layers (B) finally are usually 1 to 25 nm, preferably 5 to 20 nm, thick.

If several layer packets (A) + (B) are contained, then lowered the layer thickness of the coatings (B) is usually about about 50 to 75%.  

Furthermore, the luster pigments according to the invention can also be used have outer layer (C), in particular for protection underlying, essentially metallic or reduced (never layers (B) containing metal oxides are used.

The layer (C) can consist of low refractive index or high refractive index Metal oxides that are both colorless and selectively absorbent can be built up. Are suitable for. B. silicon dioxide, Silicon oxide hydrate, aluminum oxide, aluminum oxide hydrate, tin dioxide, titanium dioxide, zirconium dioxide, iron (III) oxide and Chromium (III) oxide, with silicon dioxide and aluminum oxide being preferred are.

Layer (C) can also be a layer containing phosphate, chromate and / or vanadate or also containing phosphate and SiO ₂ to be retained by gas phase passivation (EP-A-595 131 and DE-A-44 14 079) which, in particular, also enables the use of gloss pigments according to the invention which have a largely metallic layer (B) in water-based paints or other aqueous systems.

The thickness of layer (C) is generally about 1 to 400 nm, preferably 5 to 250 nm.

Suitable substrates for the luster pigments according to the invention finally both metallic platelets and silicate ones Platelets, each with highly refractive metal oxides can be coated, and platelet-shaped metal oxides and sulfides.

As metallic substrates such. B. in addition to steel, copper and its alloys such as brass and bronze, especially aluminum and its alloys like aluminum bronze.

Aluminum flakes that pass through in a simple manner are preferred Punching out of aluminum foil or according to common atomization and grinding techniques are to be produced.

For example, aluminum pigments are suitable, which after the so-called Hall process in white spirit by wet grinding be put. The starting material is an atomized, sparring Aluminum semolina, which in ball mills in white spirit and in Presence of a lubricant ver platelet-shaped particles is shaped or crushed and then classified.  

Commercial products can be used. However the surface of the aluminum particles should be largely free of Be fat or other supporting materials. These substances can partly by solvent treatment or better, as in the DE-A-42 23 384 described, removed by oxidative treatment will.

Of course, aluminum plates that are over physical vapor deposition (PVD) have been produced as Substrate material can be used.

Furthermore, the metallic substrate particles can be passivated be d. i.e., in particular water-stabilizing Be have layers. An example is here Farbe + Lack 97, 4/1991, pp. 311-314 and the one cited there Literature as well as referred to DE-A-42 36 332.

Metal oxide should also be used as passivating coatings layers are understood. Examples of other suitable ones Substrates are therefore iron oxide-coated metal pigments (e.g. EP-A-33 457) with golden to red intrinsic color and delicate pastel colored titanium dioxide coated metal pigments (e.g. EP-A-338 428).

In particular, light or white come as silicate substrates Mica into consideration, preferably dandruff being wet ground muscovite are particularly preferred. Of course other natural mica such as phlogopite and biotite, artificial mica, talc and glass scales can be used.

The silicate plates are already covered with one layer high refractive index metal oxide. Colorless ones are suitable for this highly refractive metal oxides such as titanium and zirconium dioxide, zinc and tin oxide and bismuth oxychloride and absorbent high refractive index Metal oxides such as iron and chromium oxides, ilmenite or mixtures of these oxides. Aluminum and silicon oxide can also, depending but only in a minor amount.

Preferred substrate materials are mica platelets, one in essential oxide coating consisting of titanium dioxide which only have small amounts (generally <5% by weight) contains further, preferably colorless, metal oxides. Such Pigments are generally known and commercially available under the designation Iriodin® (Merck, Darmstadt), Flonac® (Kemira Oy, Pori) or Mearlin® (Mearl Corporation, New York).  

The thickness of the TiO ₂ layer (geometric layer thickness) is usually 10 to 300 nm, preferably 20 to 200 nm. Particularly advantageously, mica pigments with only thin TiO ₂ coatings (approximately 20 to 40 nm) can be used as substrates.

Interesting substrate materials are also titanium dioxide-coated mica pigments, the TiO ₂ coating of which is partially reduced, and the titanium species reduced in addition to unchanged TiO ₂ with oxidation numbers <4 to 2 (lower oxides such as Ti ₃ O ₅ , Ti ₂ O ₃ up to TiO, titanium oxynitrides and titanium nitride). The reduced pigments are more color intensive than the unreduced TiO ₂ -coated pigments, and their body color shifts with increasing degree of reduction in the direction of the absorption color of the reduction products of the titanium, i.e. in the blue to violet color range. As is known, their production can be achieved by reduction with ammonia, hydrogen and also hydrocarbons and hydrocarbon / ammonia mixtures (cf. EP-A-332 071, DE-A-195 11 696 and DE-A-195 11 697 and the state described therein the technology), the pigments reduced in the presence of hydrocarbons usually also contain carbon.

Examples of further suitable substrate materials are, above all, platelet-shaped iron oxides, preferably platelet-shaped iron (III) oxide α-Fe ₂ O ₃ , with silicon (EP-A-14 382), aluminum (EP-A-68 311) or aluminum and manganese (EP-A-265 820) as well as platelet-shaped magnetite Fe ₃ O ₄ , platelet-shaped bismuth oxychloride BiOCl (EP-A-315 849) and platelet-shaped molybdenum sulfide. In principle, platelet-shaped titanium dioxide and zirconium dioxide are also suitable, but these materials can only be produced in a complex manner (US Pat. No. 4,168,986). Instead of these high-index materials, low-index silicon dioxide platelets can also be used, but these are difficult to manufacture (WO-A-93/8237). Finally, boron nitride and graphite flakes are also suitable as substrate materials.

The size of the substrate particles is not critical per se in the luster pigments according to the invention and can be matched to the particular application. As a rule, the platelet-shaped particles have average largest diameters of approximately 1 to 200 μm, in particular approximately 5 to 100 μm, and thicknesses of approximately 0.1 to 1 μm, in particular approximately 0.5 μm for metallic and approximately 0.3 µm for non-metallic substrates. Their specific free surface area (BET) is usually 0.1 to 15 m ² / g, in particular 0.1 to 5 m ² / g for metallic and 1 to 12 m ² for non-metallic substrates.

The preferred gloss pigments according to the invention show very strong and extremely angle-dependent interference colors. The effects are those in EP-A-668 329 for goniochromatic gloss pigments on a metallic basis or in DE-A-195 25 503 for goniochromatic gloss pigments based on non-metallic, (semi) transparent substrates compared effects described bar.

For the metallic gloss pigments there is a "hard" in the paint metallic shine and very good hiding power static, while the non-metallic gloss pigments in the paint softer shine, apparently coming from the deep, shows why they also create the illusion of spatial depth.

The preferred luster pigments according to the invention stand out through the uniform, homogeneous and film-like structure of their interference-capable coating from which the substrate platelets encased on all sides and not just the platelets above and below side covered.

The production is preferably carried out by multiple coating of the substrate platelets via gas phase decomposition of volatile metal compounds (CVD process) or wet chemical via hydrolytic Decomposition in particular of organic metal compounds.

The carboxylate-containing zirconium oxide layer (A) is advantageously wet-chemically by hydrolysis of a zirconium alkoxycarboxylate of the general formula II

(R-COO) Zr (OR ¹ ) ₃ II

in which R has the meaning given above and R ^{1 is} (preferably unbranched) C ₂ -C ₆ -alkyl, preferably C ₃ -C ₄ -alkyl, particularly preferably C ₃ -alkyl, in the presence of the substrate particles and an organic solvent in which the zirconium alkoxy carboxylate is soluble.

The zirconium alkoxy carboxylate II is expedient by mixing the corresponding carboxylic acid with a zirconium tetraalkoxide solution in a water-free organic Solvent produced and in the form of this solution at Be layering used.  

A favorable molar ratio of carboxylic acid to zirconium alkoxide is 0.8 to 1.2: 1, preferably about 1: 1 can also work with an excess of acid.

Particularly suitable solvents are aliphatic alcohols, preferably C ₁ -C ₆ alcohols and particularly preferably C ₂ -C ₄ alcohols such as ethanol, propanol, isopropanol, butanol, isobutanol and tert-butanol, ethanol and isopropanol being very particularly preferred .

So much solvent is advantageously used that the zirco niumalkoxycarboxylate II as 5 to 70, preferably 10 to 40% by weight solution is present.

In the subsequent hydrolysis, at least the stoichiome amount required for the reaction of the alkoxy groups Water can be used. The increases with the amount of water Hydrolysis rate, however, also increases the probability keit that the zirconium alkoxy carboxylate next to the substrate particle hydrolyzes and precipitates and does not film on the Is deposited substrate particles. Favorable molar ratios of Water to zirconium is therefore generally <40: 1 before add 10 to 1.5: 1 and particularly preferably 5 to 1.5: 1.

The hydrolysis can be catalyzed by adding acid or base become, d. that is, the pH of the hydrolysis mixture can range from 3 to 10. However, the pH is preferably 4 to 7, d. that is, you can usually al only with the usually slightly acidic zirconium alkoxycarboxy lat solution work.

You can hydrolysis at a temperature of -20 ° C to just under below the boiling point of the solvent or solvents present make. Temperatures of 10 to 60 ° C., ins special room temperature.

A suspension of the substrate particles is expediently carried out in an organic solvent that is as anhydrous as possible, in which the zirconium alkoxy carboxylate is also soluble.

As a solvent, the above-mentioned alcohols and also polyhydric C ₂ -C ₆ alcohols such as ethylene glycol, propylene glycol or glycerol are particularly suitable, the alcohol used in the zirconium alkoxycarboxylate solution not having to be identical to the alcohol used for the suspension.

Aprotic solvents such as ketones, β-diketones, ethers, especially cyclic ethers, and nitrogen term solvents, e.g. B. also amidic solvents such as Ace clay, diethyl ketone, acetylacetone, tetrahydrofuran, dioxane, tri oxane, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, Pyridine and acetonitrile can be used.

In terms of process engineering, the coating according to the invention is used tion with the carboxylate-containing zirconium oxide expediently as follows:

Substrate particles, organic solvent and if desired, water and doses the zirconium alkoxycarb oxylate solution, preferably continuously. It is advantageous it is not to add the water, but also continuously Lich, preferably in the form of a solution or mixture with one of the mentioned organic solvents, for. B. as an aqueous alcohol, to admit.

To prevent agglomeration during the coating process can prevent the suspension of a strong mechanical bean such as pumping, vigorous stirring or exposure to Ultra be subjected to sound.

The isolation of the carboxylate-containing zirconium oxide layer (A) coated substrate particles can usually after a stirring time of about 1 to 6 hours by filtering, washing with organic solvent and subsequent drying (in general 2 to 24 h at 20 to 200 ° C, under normal pressure or reduced pressure).

With the help of the method according to the invention, the carboxylate containing zirconium oxide layer (A) without problems even in higher ones Layer thicknesses (<100 nm) in good quality, d. that is, as together hanging, interference-capable film can be applied.

The further covering with the layers (B) according to the invention preferably follows the CVD method, depending on desired layer material different reaction conditions are to be set and the reaction temperature is more appropriate as 350 ° C, preferably 300 ° C, should not exceed, since the carboxylate-containing zirconium oxide layer (A) then begins to carb cleave off oxylate and convert into a zirconium dioxide layer walk.  

As known from WO-A-93/12182, metallic layers (B) are preferably applied by decomposing metal carbonyls such as iron pentacarbonyl, chromium, molybdenum, tungsten hexacarbonyl, nickel tetracarbonyl and / or dicobalt octacarbonyl at 70 to 350 ° C. under inert conditions . For the decomposition of the particularly preferred Mo (CO) _6, temperatures of 200 to 250 ° C. are particularly suitable.

Aluminum layers (B) can, as in DE-A-195 16 181 be wrote, by inert gas phase decomposition of aluminum organy len, especially aluminum alkyls such as triethyl and trimethyl aluminum at preferred temperatures of 150 to 350 ° C be divorced.

The reactor described in particular in WO-A-93/12182 bene fluidized bed reactor preferred, but you can also one Use a round neck flask made of quartz glass that has a motor is rotated with gas inlets and outlets in the axis of rotation hen and is heated by a double-shell folding oven (rotary ball oven). In principle, any heatable mixer, who shot the substrate particles by means of appropriate internals Moving and allowing gas supply and discharge, as a reactor deploy. For continuous process management in techni cal scale is suitable for. B. also a rotary kiln, which the Substrate particles and the aluminum alkyl / inert gas mixture be fed continuously.

Finally, metallic layers (B) can also be wet-chemically applied by reduction from suitable metal salt solutions will. In this way, nobler metals such as ins special silver, also copper, gold, cobalt, nickel, palladium and platinum are deposited. As described in EP-A-353 544 ben, a number of reducing agents are suitable, ins special mild organic reducing agents, e.g. B. Sugar such as glu cose and dextrose and also formaldehyde.

As a rule, however, those applied via the gas phase Metal layers due to their higher quality (finer crystalline lin, film-like) to be preferred over the wet-chemical applied, since they usually result in more brilliant and more intense gloss pigments.

The CVD deposition of non-selectively absorbing layers (B) which essentially consist of lower metal oxides (e.g. Fe ₃ O ₄ , VO ₂ , V ₂ O ₃ ) is also known from WO-A-93/12182. The metal carbonyls such as iron pentacarbonyl or oxychlorides such as vanadium oxychloride are replaced with water vapor. If higher metal oxides such as V ₂ O ₅ initially form during the gas phase decomposition, these must subsequently z. B. can be reduced to the desired oxide with hydrogen or ammonia.

As described in EP-A-579 091 and DE-A-195 15 988, can non-selectively absorbing layers containing metal sulfide (B) applied to the substrate particles coated with (A) by making it more volatile, preferably by gas phase decomposition Metal compounds in the presence of an inert gas or acid substance and / or water vapor first a metal or metal oxide deposits and then this by implementation with a volatile sulfur-containing compound or with sulfur vapor in the desired metal sulfide-containing layer (B) is transferred or the Layer (B) directly by gas phase decomposition of volatile metal separates compounds in a sulfur-containing atmosphere.

In addition to the sulfur-containing organi mentioned in EP-A-579 091 connections are the preferred sulfur suppliers ins special hydrogen sulfide and especially sulfur itself too call.

When using elemental sulfur, one goes procedural nisch appropriately so that you have finely ground sulfur powder into the reactor together with the substrate material, inertized for about 1 to 4 h and then with the exclusion of Oxygen heated to about 300 to 350 ° C.

Suitable reactors for coating are Reactors called aluminum.

Any existing sulfur residues can be sublimated Remove easily in an inert gas stream. Usually, however not be necessary because the sulfur is quantitative (up to that for the formation of the metal sulfide stoichiometrically required Quantity) is implemented and therefore easily in the desired Sulfide content of layer (B) corresponding amount added that can. So much sulfur is preferably used that the preferred metallic or the oxidic starting layer at least least covered by a coherent, dense layer of sulfide which makes further passivation unnecessary. The inside (n region of the layer (B) lying towards the substrate) can be na have no sulfide and essentially only from the respective metal (or metal oxide).

Also for the production of selectively absorbing layers (B) which in essentially made of colored metal oxides or metal nitrides hen, CVD methods already described are particularly suitable.  

So is the deposition of α-iron (III) oxide or chromium (III) oxide through oxidative decomposition of iron pentacarbonyl or chromium hexa carbonyl at 200 to 250 ° C well known (EP-A-33 457).

Wet-chemical could α-Fe ₂ O ₃ and Cr ₂ O ₃ layers by hydrolytic decomposition of iron (III) salts such as iron (III) chloride and sulfate or chromium (III) chloride and subsequent transfer of the hydroxide-containing layers formed Annealing can be applied in the oxide layers. A Ti ₂ O ₃ coating could also be achieved by hydrolysis of TiCl ₄ and subsequent reduction of the formed TiO ₂ with hydrogen or ammonia.

The coating with selectively absorbing γ-Fe ₂ O ₃ (B) can follow the CVD process variants described in DE-A-43 40 141, by first depositing a magnetite film by decomposing Fe (CO) ₅ in the presence of water vapor is, which is then oxidized with air to γ-Fe ₂ O ₃ , or first an α-Fe ₂ O ₃ film is deposited by oxidative decomposition of Fe (CO) ₅ , which with hydrogen to iron (II) containing products reduced and then oxidized to γ-Fe ₂ O ₃ with air. Temperatures of 200 to 350 ° C are suitable for all of these process steps.

Vanadium (V) oxide layers (B) can be decomposed by gas phase Vanadium oxychloride can be separated with water vapor.

Titanium nitride coatings can finally be produced by gas phase decomposition of tetrakis (dialkylamido) titanium complexes Ti (NR ₂ ) ₄ (R: in particular methyl or ethyl) in the presence of ammonia at 200 to 350 ° C (Chemistry of Materials, 3, 1138-1148 (1991 )).

Colorless high refractive index layers (B), which consist essentially of Titanium dioxide or zirconium dioxide can be wet-chemical by hydrolysis of inorganic salts of the metals applied the, then dried or annealed at a maximum of 350 ° C is (DE-A-20 09 566 and US 3 087 828 or the beginning literature).

Outer protective layers (C) consisting essentially of colorless or consist of selectively absorbing metal oxides the processes already described by oxidative or hydroly table gas phase decomposition of the metal carbonyl or the metal alcoholates or wet chemical by hydrolysis of organic metal compounds (silicon, aluminum) or inorganic metal salts be generated.  

SiO ₂ layers (C) can be wet chemically by hydrolysis of silicon alcoholates such as tetraethoxysilane in the presence of an alcohol and of aqueous ammonia (DE-A-44 05 492) or by gas phase decomposition of silanes containing alkanoyloxy radicals such as di-tert-butoxydiacetoxysilane in the presence of Water vapor at 150 to 300 ° C (DE-A-44 37 752) are separated.

Phosphate-, chromate- and / or vanadate-containing as well as phosphate- and SiO ₂ -containing outer layers (C) can, according to the passivation processes described in EP-A-595 131 and in DE-A-44 14 079, be carried out by hydrolytic or oxidative Gas phase decomposition of oxide halides of metals (e.g. CrO ₂ Cl ₂ , VOCl ₃ ), in particular phosphorus oxyhalides (e.g. POCl ₃ ), phosphoric and phosphoric acid esters (e.g. di- and trimethyl and ethyl phosphite ) and from amino groups containing silicon organyls (e.g. 3-aminopropyltriethoxy and trimethoxysilane).

Luster pigments, which are particularly stable in aqueous systems, with combined decomposition of the phosphorus and silicon ver get ties.

The luster pigments according to the invention are advantageously suitable for many purposes, such as for coloring plastics, glasses, kera mix products, preparations of decorative cosmetics and be especially of paints, especially automotive paints, inks and Printing inks, especially security printing inks. For the applica tion in printing are all known printing processes, e.g. B. screen printing, Gravure, bronzing, flexo and offset printing, suitable.

The pig according to the invention can be used for these purposes elements also advantageous when mixed with transparent and opaque White, colored and black pigments as well as conventional ones transparent, colorful and black gloss pigments on the base of metal oxide coated mica and metal pigments, platelet-shaped iron oxides, graphite, molybdenum sulfide and Use platelet-shaped organic pigments.

Examples Production and use of gloss pigments according to the invention

When the pigments were incorporated into the varnish, 0.4 g each Pigment in 3.6 g of a polyester mixed lacquer with 21% by weight solids Stir in the material and dispersed in the Red Devil for 2 min. With  a doctor blade (160 µm wet film thickness) were placed on black and white cardboard Prints of the pigmented varnish made.

example 1

• a) In a round-bottom flask equipped with a reflux condenser and stirring apparatus, 100 g of aluminum powder (BET surface area 1.2 m ² / g, average particle size 59.6 μm) were suspended in 2000 ml of isopropanol. Then 23.5 ml of an aqueous ethanol solution (26.5% by weight of water) and 400 ml of a solution of 77 g of zirconium tetra-n-propoxide, 21.5 g of benzoic acid and 320 ml of isopropanol were metered in at a rate of 3 ml / h or 40 ml / h added.
  After a stirring time of 1 h, the product was filtered off, washed thoroughly with isopropanol and dried under reduced pressure at room temperature.
  144 g of a pigment with a zirconium content of 10.2% by weight and a carbon content of 10.1% by weight were obtained which, when the reaction mixture was spotted on filter paper, showed a weak color which changed from red to green gold.
  IR spectrum (DRIFT): bands at 1590, 1540, 1440, 1430, 720 and 670 cm⁻ ¹
• b) 125 g of the pigment obtained in a) were then heated to 230 ° C. in a fluidized bed reactor (described in EP-A-571 836) with fluidization using a total of 700 l / h of nitrogen.
  From a template heated to 70 ° C., 23 g of molybdenum hexacarbonyl were transferred into the reactor in 6 h with a nitrogen stream of 200 l / h and decomposed into molybdenum and carbon monoxide.

The pigment obtained had a molybdenum content of 4.6% by weight, a zirconium content of 9.8% by weight and a carbon content of 8.2% by weight and, when applied in the lacquer, showed almost no loss strong metallic shine changes a strong, red interior reference color, which at steeper viewing angles according to green gold tipped over.  

Example 2

• a) Analogously to Example 1a), 75 g of finer aluminum powder (BET surface area 4.5 m ² / g, average particle size 20.1 μm) in 1500 ml of ethanol using 67 ml of the aqueous ethanol solution (26.5% by weight) % Water) and 920 ml of a solution of 177 g of zirconium tetra-n-propoxide, 49.5 g of benzoic acid and 650 ml of ethanol coated with benzoate-containing zirconium oxide.
  There were 178 g of a pigment with a zirconium content of 19.5% by weight and a carbon content of 20.1% by weight, which showed a weak color changing from green to blue on filter paper.
• b) Analogously to Example 1b), 160 g of the pigment obtained in a) were coated with molybdenum in 12 h using 40 g of Mo (CO) ₆ .

The pigment obtained contained 14.3% by weight of Mo, 18.9% by weight of Zr and 16.7% by weight C and, when applied in the lacquer, showed almost unchanged strong metallic shine a strong, green interference color that tipped to blue at steeper viewing angles.

Example 3

• a) 75 g of a silver-colored TiO ₂ -coated mica pigment (Iriodin® 103 rutile sterling silver, Merck; BET surface area 8.4 m ² / g, average particle size 20.1 μm) were in a round-bottomed flask provided with a reflux condenser and a stirring apparatus 1500 ml of ethanol suspended. Then 75 ml of an aqueous ethanol solution (26.5% by weight of water) and 1250 ml of a solution of 240 g of zirconium tetra-n-propoxide, 67.5 g of benzoic acid and 1000 ml of ethanol were run in parallel at a metering rate of 3 ml / h or 50 ml / h added.
  193 g of a pigment with a zirconium content of 21.9% by weight and a carbon content of 21.2% by weight were obtained, which showed a weak color changing from green to red on filter paper.
• b) Analogously to Example 1b), 166 g of the pigment obtained in a) were coated with molybdenum in 12 h using 41 g of Mo (CO) ₆ .

The pigment obtained contained 6.7% by weight of Mo, 21.0% by weight of Zr and 16.0% by weight of C and, when applied in the lacquer, showed a green inter reference color, which at steeper viewing angles according to Rotvio lett dumped.

Claims (10)

1. Coat goniochromatic gloss pigments on the basis of multiple coats teter platelet-shaped substrates containing a carboxylate Contain zirconium oxide layer as a low refractive index layer. 2. Gloss pigments according to claim 1, in which the zirconium oxide layer is a carboxylate of the general formula I.
R-COO ^⊖ I
in the
R is phenyl or naphthyl, which can in each case be substituted by C ₁ -C ₄ alkyl or alkoxy, means C ₁ -C ₉ alkyl or hydrogen. 3. Gloss pigments according to claim 1 or 2, in which the mol ratio of carboxylate to zirconium is 0.5 to 1.5: 1. 4. luster pigments according to claims 1 to 3, in which the substrate flakes from at least one layer package

• A) a carboxylate-containing zirconium oxide layer and
• B) a reflective layer which is at least partially transparent to visible light,

as well as additional if desired

• C) an outer protective layer

exhibit. 5. Gloss pigments according to claims 1 to 4, in which the Layer (B) consists essentially of metals, metal oxides, Me tall sulfides or metal nitrides or mixtures thereof stands. 6. gloss pigments according to claims 1 to 5, in which the Layer (C) consists essentially of colorless or selective sorbent metal oxides and / or phosphate, chro contains mat and / or vanadium.   7. gloss pigments according to claims 1 to 6, only one Have layer package (A) + (B). 8. gloss pigments according to claims 1 to 7, in which the platelet-shaped substrate essentially made of metal platelets, silicate platelets that are already high refractive metal oxides are coated, platelet-shaped Metal oxides, platelet-shaped metal sulfides, graphite platelets Chen or boron nitride platelets or mixtures thereof. 9. Use of gloss pigments according to claims 1 to 9 for coloring paints, printing inks, inks, plastics, Glasses, ceramic products and preparations from dekora tive cosmetics. 10. A method for coating a pigmentary substrate with a carboxylate-containing zirconium oxide layer, characterized in that a zirconium alkoxy carboxylate of the general formula II
(R-COO) Zr (OR ¹ ) ₃ II
in the
R is phenyl or naphthyl, which can in each case be substituted by C ₁ -C ₄ alkyl or alkoxy, means C ₁ -C ₉ alkyl or hydrogen and
R ^{1 represents} C ₂ -C ₆ alkyl,
hydrolytically decomposed in the presence of the substrate particles and an organic solvent in which the zirconium alkoxy carboxylate is soluble.