Glossy black interference pigments

The present invention relates shiny black interference pigments based on a substrate mixture, the high- and low-index comprises layers and their use in paints, coatings, Powder coatings, printing inks, plastics, ceramic materials, Glasses, in cosmetic formulations, for laser marking and Preparation of pigment compositions and dry preparations.

Luster or effect pigments are used in many areas of technology, in particular in the field of automotive coatings, decorative coatings, in plastics, paints, printing inks and in cosmetic Formulations.

Black pigments are often based on carbon. Such Examples of pigments are known from the published patent applications DE 42 27 082 A1, DE 36 36 076 A1, DE 36 17 430 A1, and EP 0246523 B1. The production of the black luster pigments either through the use of carbon black, due to decomposition processes of organic compounds or by temperature-dependent calcination of hydrocarbons.

The processes known from the prior art black luster pigments have the disadvantage that they are distinguished by a dull luster and a gray-black or brown-black color distinguished.

EP 0753545 B1 discloses goniochromatic luster pigments Based on multiply coated, high refractive index for visible light at least partially permeable, nonmetallic, platelet-shaped Substrates as with absorbing high refractive metal oxides Iron and chromium oxides, ilmenite or also mixtures of these oxides, are occupied, known that at least one layer packet colorless from a low refractive index and a reflective, selectively or nonselectively exhibit absorbing coating. The prior art known luster pigments showing interference colors very much on the Viewing angles are dependent on what the majority of applications is not desirable. Furthermore, these pigments are in some very difficult prepare or reproduce.

Object of the present invention is therefore an inorganic find pigment that has a glossy pure black and simultaneously by a high opacity and good processability distinguished and no pronounced goniochromaticity possesses.

Surprisingly, now black interference pigments with high gloss found based on a substrate mixture containing a certain arrangement of optically functional layers, thereby Special color and gloss effects. On a substrate mixture based on platelets is different particle sizes first creates a defined absorption (absorption layer) and then it through the use of multilayer technology and the Based on at least one low refractive semitransparent and optionally an absorbent layer, an interference system implemented. This combination of absorption and interference results in a final black interference pigment with high gloss and an exceptionally high hiding power.

The black interference pigments according to the invention are distinguished by a high degree of blackness (low L value, a or b values are from around the zero point) and an intense shine.

The invention thus shiny black interference pigments on the basis of a substrate mixture, characterized in that<sl><li>(A) a coating of Fe₃O₄.</li><li>(B) a colorless coating consisting of one or more Layers each having a refractive index n ≤ 1.8</li><li>(C) optionally a non-coverage occupancy by absorbing high-index material, and optional</li><li>(D) an outer protective layer</li></sl>having.

The invention furthermore relates to the use of the inventive Pigments in paints, coatings, powder coatings, printing inks, plastics, ceramic materials, glasses and for laser marking. Due to the high color strength and good skin feel are the inventive toxic acceptable pigments in particular for decorative cosmetics suitable. Furthermore, the invention can Pigments for the production of pigment preparations and for the preparation of dry preparations, such as granules, chips, pellets, Briquettes, sausages, etc., are used. The dry preparations may, in particular in cosmetic formulations, printing inks and Lacquers are used.

A suitable base substrate for black inventive Pigments is a mixture of coarse and fine transparent platelet-shaped substrates. Preferred substrates are phyllosilicates. Especially suitable are natural and / or synthetic mica, Talc, kaolin, platelet-shaped iron oxides or aluminum, glass, SiO₂-, TiO₂-, Graphite platelets, synthetic support-free flakes, platelets BiOCl or other comparable materials.

The size of the base substrates is defined by the target Black and gloss level or opacity and has this each adapted will. In general, the platelet-shaped substrates have a thickness between 0.05 and 5 .mu.m, in particular from 0.1 to 4.5 microns. The Extension in the other two dimensions is usually 1 to 200 .mu.m, preferably 1-150 .mu.m, and more particularly 1-130 microns.

Wherein the base substrate is the same or mixtures of various substrates each with different particle sizes. The substrate mixture can consist of two, three or more different Substrates made. Preferably, the substrate mixture consists only of a substrate with two different particle sizes. furthermore preferred substrate mixtures consisting of synthetic mica, SiO₂-, TiO₂- Or glass flakes.

The substrates can be mixed in any ratio. In usually be coarse flakes with particle sizes of 10 to 200 microns, preferably from 40 to 200 microns, and especially from 10 to 130 microns with fine flakes having particle sizes of 1 to 60 .mu.m, preferably from 5 to 60 microns, and especially from 10 to 60 microns, together prior to Occupancy mixed. For good Redaction of the pigment with good gloss, the ratio of fine and coarse substrate particles crucial. Preferably, coarse and fine substrates Substrate mixture in the ratio 10: 1 to 1: 10, in particular in Ratio of 5: 1 to 1: 5, mixed. Especially preferred are 1: 1 mixtures. Preferred substrate mixtures consisting of mica flakes with different particle sizes. Particularly preferred substrate mixtures consist of coarse and fine platelets, particularly from south-mica (&gt; 125 microns) and F-mica (&lt;25 microns).

The thickness of the individual layers on the base substrate is essential for the optical properties of the pigment. In particular, the layer (A) substantially affect the color characteristics. The layer (B) should opposite the layer (A) be relatively thin. For a pigment with high color force has the thickness of the individual layers to each other exactly be adjusted.

The interference pigments of the invention have alternating one high refractive index layer (A) or (C) and a low refractive index layer (B). The high-index layers (A) and (C) have a Refractive index of n&gt; 1.8, preferably n ≥ 2.0.

The thickness of the Fe₃O₄Layer (A) is preferably 1 to 350 nm, in particular from 50 nm to 300 nm, and very particularly preferably from 100 to 250 nm.

Colorless low refractive index for the coating (B) suitable Materials are preferably metal oxides or the corresponding Oxide hydrates, such as SiO₂, Al₂O₃, AlO (OH), B₂O₃, ZnSiO₄, MgF₂, MgSiO₃. or a mixture of said metal oxides. Preferably , the layer (B) consists of SiO₂, MgF₂ or Al₂O₃ or mixtures thereof. The low refractive index layer (B) may consist of a low refractive index Layer or low refractive index of a package of two or more Layers. Preferably, the layer (B) consists of a or two low refractive index layers of the composition forth are not identical, but their thicknesses are identical or different could be. Preferably, the layer (B) consists of a SiO₂-Layer and / or an Al₂O₃-Layer.

For the optical properties of the pigments of the invention, it is advantageous if the layer (B) is relatively thin. The thickness of the layer (B) is independent of the number of the individual layers from 1 to 350 nm, preferably 50 to 300 nm and especially 20 to 250 nm.

Insofar as the final layer, the absorbing high refractive index layer (C) is applied, so this is only in low concentrations of preferably 2-5 wt.%, in particular 2-3 wt.%, based on the Substrate mixture used in place and thus does not form closed layer. The layer (C) preferably consists of Fe₃O₄. furthermore from black sulfides, oxynitrides, or mixtures thereof. The final layer (C) is used to further optimize the gloss.

The coating of the substrates with a high refractive index layer (A), a low refractive index layer (B), and optionally a further black high refractive index layer (C) formed black interference pigments, their luster, coverage varied widely can be.

Particularly preferred interference pigments have the following layer sequences on:<sl><li>Substrate mixture + Fe₃O₄ (A) + SiO₂ (B)</li><li>Substrate mixture + Fe₃O₄ (A) + SiO₂ (B) + Al₂O₃ (B)</li><li>Substrate mixture + Fe₃O₄ (A) + SiO₂ (B) + Fe₃O₄ (C)</li><li>Substrate mixture + Fe₃O₄ (A) + SiO₂ (B) + Al₂O₃ (B) + Fe₃O₄ (C)</li><li>Substrate mixture + Fe₃O₄ (A) + Al₂O₃ (B)</li><li>Substrate mixture + Fe₃O₄ (A) + Al₂O₃ (B) + SiO₂ (B)</li><li>Substrate mixture + Fe₃O₄ (A) + Al₂O₃ (B) + Fe₃O₄ (C) </li><li>Substrate mixture + Fe₃O₄ (A) + Al₂O₃ (B) + SiO₂ (B) + Fe₃O₄ (C)</li></sl>

By combination of absorption and interference on a definable substrate mixture to obtain a black shiny Interference pigment with an adjustable amount of color. The defined Setting the A and B values ​​it is possible to black the interference pigments to obtain with a gold, green, red or blue tint.

The interference pigments according to the invention can be relatively easily Making high by the generation and low refractive index interference layers with precisely defined thickness and smooth surface on the finely divided, platelet-shaped substrates.

The metal oxide layers are preferably applied by wet-chemical, being developed for the preparation of pearlescent pigments wet chemical Coating process can be applied. Such Methods are described for example in DE 14 67 468, DE 19 59 988 DE 20 09 566, DE 22 14 545, DE 22 15 191, DE 22 44 298, DE 23 13 331, DE 25 22 572, DE 31 37 808 DE 31 37 809, DE 31 51 343, DE 31 51 354, DE 31 51 355, DE 32 11 602 DE 32 35 017 or known in other to those skilled in patent documents and other publications.

Before the assignment, first the substrate mixture of coarse and fine flakes prepared by simple mixing. In the wet coating substrate mixture is suspended in water and with one or more hydrolysable metal salts in a for Hydrolysis suitable pH value offset, which is chosen so that the Metal oxides or metal oxide hydrates are precipitated directly onto the flakes be without the secondary precipitations. The pH is usually by simultaneous metered addition of a base or acid kept constant. The SiO₂is layer usually made of soda or Potassium silicate produced. The pigments are subsequently separated, washed and dried and in a reducing atmosphere preferably annealed under forming gas, wherein the annealing temperature in Terms can be optimized for the particular coating present. In general, the calcination temperatures are between 500 and 900 ° C. Preferably, the forming gas is the composition N₂ or Argon having a concentration of 4-10% H₂, Especially 4-8% and most preferably with 8% H₂ reduced. In particular, there is a employed forming gas consisting of 92% N₂ and 8% H₂, If desired, can separated the pigments after application of individual coatings, are dried and optionally calcined and then the precipitation of the further Layers to be resuspended. Furthermore, the Coating in a fluidized bed reactor by gas-phase coating take place, where, for example: in EP 0 045 851 and EP 0106235 for the production of pearlescent pigments proposed method can be applied accordingly.

The color tone of the pigments can vary within wide limits by varying Choice of the coating amounts or the layer thicknesses resulting therefrom be varied. The fine tuning for a certain hue can the pure choice of amount by visually or by measurement controlled approaching the desired color can be achieved.

To increase the light, water and weather stability, it is recommended frequently, depending on the application area, the finished pigment to to undergo post-coating or post-treatment. Suitable post or post-treatments, for example, in the DE-PS 22 15 191, DE-OS 31 51 354, DE-OS 32 35 017 or DE-OS process described in question 33 34 598th Through this Resurfacing (layer D) is the chemical stability further increased or the handling of the pigment, especially its incorporation into various media. To improve the wettability, Dispersibility and / or compatibility with the user media functional coatings of Al₂O₃ or ZrO₂ or their Mixtures are applied to the pigment surface. Furthermore, organic post possible, for example with silanes such as described in EP 0090259, EP 0634459, WO 99/57204, WO 96/32446, WO 99/57204, US No. 5,759,255, US 5,571,851, WO 01/92425 or in JJ Ponjeé, Philips Technical Review, Vol. 44, No. 3, 81 ff., And PH Harding JC Berg, J. Adhesion Sci. Technol. Vol. 11 No. 4, pp 471-493.

It goes without saying that for the various applications, Interference pigments according to the invention also advantageous in Blend with organic dyes and / or pigments, such as transparent and opaque white, colored and black pigments, and with platelet-organic pigments, holographic Pigments, LCPs (liquid crystal polymers) and conventional transparent, colored and black luster pigments based on metal oxide-coated flakes based on mica, glass, Al₂O₃. Fe₂O₃, SiO₂, Etc., may be used. The invention black interference pigments can in any proportion commercially available pigments and fillers are mixed.

Examples of suitable fillers can be mentioned natural and synthetic mica, Nylon powder, pure or filled melamine 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. With respect to the particle shape of the filler there are no restrictions. You can meet the requirements in accordance with lamellar example, be spherical or needle-shaped.

The pigments of the invention are due to their good skin adhesion particularly suitable for cosmetic formulations, both in Decorative cosmetics as well as for personal care products. In the use of the inventive pigments with dyes, Carbon black and / or other effect pigments can be with them particularly achieve effective effects in the various application media, for example, in cosmetic formulations such as mascara, eyeliner, Eyeliner.

The pigments of the invention may in the Formulations with any type of cosmetic raw materials and auxiliaries be combined. These include oils, greases, waxes, film formers, Preservatives and general performance properties determining additional materials such as thickeners and rheological Additives such as bentonites, hectorites, silicon dioxides, Ca silicates, Gelatin, high molecular weight carbohydrates and / or surfactants Tools, etc.

The pigments of the invention containing formulations can belong to the lipophilic, hydrophilic or hydrophobic type. at heterogeneous formulations having discrete aqueous and non-aqueous Phases pigments of the invention in only one of the contain two phases or alternatively distributed over both phases.

The pH values ​​of the formulations can be between 1 and 14, preferably 2-11 and particularly preferably 5 to 8 The concentrations of the interference pigments according to the invention in the Formulation are no limits. You can - depending on the Application - between 0.001 (rinse-off products, for example shower gels) - 100% (for example luster-effect articles for particular applications). The pigments of the invention can continue with cosmetic combined active ingredients. Suitable active ingredients are, for example,

Insect repellents, UV A / BC protective filters (for example OMC, B3, MBC), anti-aging agents, Vitamins and derivatives thereof (for example vitamin A, C, E, etc.), Self (eg DHA, erythrulose etc.) and further cosmetic Active ingredients such as bisabolol, LPO, ectoine, emblica, allantoin, Bioflavonoids and derivatives thereof.

The pigments of the invention are also suitable for the preparation of flowable pigment compositions and dry preparations comprising one or more pigments, binders and optional according to the invention one or more additives. Under dry preparations are preparations To understand the 0 to 8 wt.%, preferably 2 to 8 wt.%, especially 3 to 6 wt.%, of water and / or a solvent or Solvent mixture contained. The dry preparations are preferably form of pellets, granules, chips, sausages or briquettes and have particle sizes of 0.2-80 mm. Find The dry preparations particular application in the production of printing inks and in cosmetic formulations.

The pigments of the invention are provided with a plurality of color systems compatible preferably from the area of ​​paints, coatings and printing inks. For the preparation of printing inks, a plurality of of Binders, in particular water-soluble grades, is suitable, such as those of BASF, Marabu, Pröll, Sericol, Hartmann, Gebr. Schmidt, SICPA, Aarberg, Siegberg, GSB-Wahl, Follmann, Ruco or Coates Screen INKS GmbH are sold. The printing inks can in Water-based or solvent-based be constructed. Furthermore, the Pigments for the laser marking of paper and plastics, and for applications in the agricultural sector, for example for greenhouse sheeting, and z. B. for the coloring of tarpaulins suitable.

The invention furthermore also relates to the use of the pigments in formulations such as paints, printing inks, security printing inks, Varnishes, powder coatings, plastics, ceramic materials, Glasses, in cosmetic formulations, as a dopant for the Laser marking of papers and plastics and for the production of Pigment compositions and dry preparations.

The following examples illustrate the invention without it however, limiting it.

Examples

Example 1 (mica + Fe₃O₄ + SiO₂ + Al₂O₃)

step 1.1

42 g S-mica (10-130 microns) and 18 g F-mica (1-15 microns) are in suspended 1.0 l of demineralized water and heated with vigorous stirring to 80 ° C. The mica suspension is treated with 10% sulfuric acid to pH = 2.8 set. To this suspension 46.05 g of iron (II) sulfate and 503.49 g of iron (III) chloride solution (w_Fe) = 15%) are metered in, the pH with sodium hydroxide solution (32%) is kept constant. During the Assignment be made color measurements. The dosage of the Iron (III) chloride solution is interrupted when the hue angle 56 ° and 59 ° is reached. The suspension is further 60 minutes at 80 ° C stirred and the pH is adjusted with sodium hydroxide solution (w = 32%) at pH = 7 set. Subsequently, 266.52 g of sodium silicate solution (Prepared from 133.26 g of sodium silicate (w_SiO2) = 27% and 133.26 g Demineralized water) are metered in, the pH constant with 10% hydrochloric acid is maintained at pH = 7.0. After the addition of the precipitant solution stirred for a further 30 minutes. Lastly, 96.64 g of aluminum sulfate solution (Prepared from 24.16 g of aluminum sulfate heptahydrate in 72.48 g of demineralized water) are metered in, the pH was adjusted with 32% sodium hydroxide constant is maintained. The suspension is stirred at 80 ° C for 30 minutes. to Workup is filtered, the pigment washed with deionized water, at dried 110 ° C and 30 min at 575 ° C. under forming gas (8% H₂/ 92% N₂) Annealed.

This gives intense glossy black interference pigments, the following have color values ​​(Minolta colorimeter CR 300):<tables><table><tgroup cols="2"><tbody><row><entry align="left">L value</entry><entry align="right">30 → 32</entry></row><row><entry align="left">a value</entry><entry align="right">0 → 1</entry></row><row><entry align="left">b-value</entry><entry align="right">-2 -4 →</entry></row><row><entry align="left">C-value (color strength)</entry><entry align="right">2 → 4</entry></row></tbody></tgroup></table></tables>

Example 2 (mica + Fe₃O₄ + SiO₂ + Fe₃O₄)

50 g N mica (10-60 microns) and 50 g F-mica (1-15 microns) are in 1.2L suspended demineralized water and heated with vigorous stirring to 80 ° C. The Mica suspension is adjusted with 10% hydrochloric acid to pH = 3.2. To this suspension are 153.05 g of iron (III) chloride solution (w_Fe) = 15%) diluted with 612.2 g deionized water are metered in, the pH with Sodium hydroxide solution (32%) is kept constant. During the occupation, Color measurements are made. The suspension is further 30 stirred for minutes at 80 ° C and the pH is adjusted with sodium hydroxide solution (w = 32 %) Adjusted to pH = 7.0. Subsequently, 290 g of sodium silicate solution (Made of 145 g of sodium silicate (w_SiO2) = 27% and 145 g of demineralized water) are metered in, the pH with 10% hydrochloric acid is kept constant at pH = 7.0. After the addition of the precipitant is stirred for further 30 minutes. Lastly, 65.40 g of iron (III) chloride solution (w_Fe) = 15%) are metered in at pH 3.2, the pH-value with 32% sodium hydroxide solution is maintained constant. The suspension is 30 stirred minutes at 80 ° C with NaOH (32%) adjusted to pH 7.0. to Workup is filtered, the pigment washed with deionized water, at dried 110 ° C and 30 min at 575 ° C. under forming gas (8% H₂/ 92% N₂) Annealed.

This gives intense glossy black interference pigments, the following have color values ​​(Minolta colorimeter CR 300):<tables><table><tgroup cols="2"><tbody><row><entry align="left">L value</entry><entry align="right">36 → 38</entry></row><row><entry align="left">a value</entry><entry align="right">-1 → 0</entry></row><row><entry align="left">b-value</entry><entry align="right">-9 -6 →</entry></row><row><entry align="left">C-value (color strength)</entry><entry align="right">9 → 6</entry></row></tbody></tgroup></table></tables>

<u>application examples</u>

Example A: cream mascara (O / W)

<tables><table><tgroup cols="3"><tbody><row><entry align="left"><u>Phase A:</u></entry><entry align="right">15%</entry><entry align="left">Interference pigment from Example 2</entry></row><row><entry align="left"><u>Phase B:</u></entry><entry align="right">8th %</entry><entry align="left">Stearic acid (1)</entry></row><row><entry align="left" /><entry align="right">6%</entry><entry align="left">Beeswax (1)</entry></row><row><entry align="left" /><entry align="right">4%</entry><entry align="left">Carnauba wax (2)</entry></row><row><entry align="left" /><entry align="right">3%</entry><entry align="left">Eutanol (3)</entry></row><row><entry align="left" /><entry align="right">2%</entry><entry align="left">Arlacel 83 V (4)</entry></row><row><entry align="left" /><entry align="right">0.1%</entry><entry align="left">Propylparaben (1)</entry></row><row><entry align="left" /><entry align="right">0.5%</entry><entry align="left">Tocopherol acetate (1)</entry></row><row><entry align="left"><u>Phase C:</u></entry><entry align="right">50.84%</entry><entry align="left">water</entry></row><row><entry align="left" /><entry align="right">2.3%</entry><entry align="left">Triethanolamine (1)</entry></row><row><entry align="left" /><entry align="right">8th %</entry><entry align="left">Shellac (5)</entry></row><row><entry align="left" /><entry align="right">0.25</entry><entry align="left">Methylparaben (1)</entry></row><row><entry align="left" /><entry align="right">0.01%</entry><entry align="left">Biotin (1)</entry></row></tbody></tgroup></table></tables>

preparation:

All constituents of phase B together at about 80 ° C to melt, is stir until everything is melted. The interference pigments of the phase A Stir. Shellac solve the phase C in water, heated to 75 ° C. The remaining constituents of phase C, solve. slowly at 75 ° C. stirring enter the phase C to phase A / B, 2 min homogenize. The mass allowed to cool with stirring to room temperature.

Sources:

<sl><li>(1) Merck KGaA</li><li>(2) Kahl &amp; Co</li><li>(3) Cognis GmbH</li><li>(4) Uniqema</li><li>(5) Paroxite Ltd.</li></sl>

Example B: Eyeliner

<tables><table><tgroup cols="3"><tbody><row><entry align="left"><u>Phase A:</u></entry><entry align="right">20%</entry><entry align="left">Interference pigment from Example 1</entry></row><row><entry align="left" /><entry align="right">2%</entry><entry align="left">Ronasphere® (1)</entry></row><row><entry align="left" /><entry align="right">0.4%</entry><entry align="left">Carpobol EDT 2001 (2)</entry></row><row><entry align="left" /><entry align="right">qs</entry><entry align="left">Citric acid (1)</entry></row><row><entry align="left" /><entry align="right">ad 60</entry><entry align="left">water </entry></row><row><entry align="left"><u>Phase B:</u></entry><entry align="right">4.0%</entry><entry align="left">Glycerin, anhydrous (1)</entry></row><row><entry align="left" /><entry align="right">0.9%</entry><entry align="left">Triethanolamine (1)</entry></row><row><entry align="left" /><entry align="right">2.0%</entry><entry align="left">Luviskol.RTM VA 64 Powder (3)</entry></row><row><entry align="left" /><entry align="right">1.0%</entry><entry align="left">Germaben II (4)</entry></row><row><entry align="left" /><entry align="right">9.7%</entry><entry align="left">water</entry></row></tbody></tgroup></table></tables>

preparation:

Interference pigment and Ronasphere® the water of phase A disperse. With a few drops of citric acid acidify the to reduce viscosity, Carpobol EDT Sprinkle with stirring. After complete dissolution of the pre-dissolved phase B slowly stir and adjust pH to 7.0-7.5.

Sources:

<sl><li>(1) Merck KGaA</li><li>(2) Noveon</li><li>(3) BASF AG</li><li>(4) ISP Global Technologies</li></sl>