Mid-tone red effect pigment

Abstract

This invention relates to an intermediate red effect pigment having high saturation and high brightness, using a metal coated with a colored absorbent layer of iron oxide or iron oxide hydroxide as a flake-shaped substrate.

Description

[Technical Field]

[0001] This invention relates to a mid-shade red effect pigment having high saturation and high brightness, using a metal coated with a colored absorption layer of iron oxide or iron oxide hydroxide as a flake-type substrate. [Background technology]

[0002] Background literature: Wissling et al., Metal Effect-Pigmente, 2nd edition, 2013, Vincentz Network GmbH; International Publication No. 2015040537; U.S. Patent Application Publication No. 20080249209; International Publication No. 2013175339

[0003] Effect pigments are used in many fields, such as automotive paints, decorative coatings, plastics, paints, printing inks, and cosmetics.

[0004] The optical effects are largely based on the direct reflection of light by flaky, parallel-oriented, metallic, or highly refractive pigment particles. Depending on the composition of the pigment flakes, interference, reflection, and absorption phenomena may occur, thereby producing angle-dependent color and brightness effects. Further details are known to those skilled in the art and can be found, for example, in Wissling et al., Metalleffekt-Pigmente, 2nd edition, 2013, Vincentz Network GmbH.

[0005] Metallic effect pigments are made from flaky substrates such as aluminum flakes or metal oxide-coated aluminum flakes. Flaky aluminum pigments with iron oxide coatings are well known and are described, for example, in Wissling et al., Metalleffekt-Pigmente, 2nd edition, 2013, Vincentz Network GmbH. They belong to the category of effect pigments and, due to their specific color properties, have been found to be widely used in coloring coatings, paints, printing inks, plastics, ceramic compositions and glazes, and cosmetic preparations.

[0006] Iron oxide-coated aluminum pigments derive their specific optical profile from a combination of specular reflection on the surface of the aluminum flake, selective light absorption in the iron oxide layer, and optical interference on the thin film surface of the iron oxide layer. This optical interference results in a color primarily determined by the thickness of the iron oxide coating. Therefore, the pigment powders exhibit colors ranging from pale yellow, greenish-gold, gold, reddish-gold, red, to violet.

[0007] Iron oxide-coated metal flakes, particularly aluminum-based flakes, are extremely bright and opaque, and therefore widely used in automotive painting. Pigments conventionally used in this field are based on aluminum flakes and exhibit a metallic, mirror-like effect. Iron oxide-coated aluminum pigments are known for their brilliant colors ranging from gold to red.

[0008] The iron oxide layer of the effect pigment can be provided to metal substrate particles by gas-phase decomposition of volatile iron compounds in the presence of oxygen and / or water vapor (so-called chemical vapor deposition), or by a wet chemical coating method (e.g., sol-gel method or precipitation method).

[0009] European Patent Application Publication No. 0033457 describes a method for producing a colored effect pigment comprising a metal substrate at least partially covered on its surface with iron oxide, in which iron pentacarbonyl is oxidized to iron oxide in a fluidized bed of the metal substrate with oxygen above 100 °C. Effect pigments with interference colors from bright gold to reddish gold are obtained. They exhibit gold colors with high brightness and high color purity, for example, in alkyd melamine resins.

[0010] In the wet chemical production method, the metal oxide-containing layer can be applied by hydrolysis reaction of a suitable metal salt; for example, an iron (III) salt, such as iron (III) chloride, iron (III) sulfate, or iron (III) nitrate, or a hydrolyzable organometallic compound. Details regarding the production of the metal oxide coating layer on the metal-based substrate of the effect pigment are provided, for example, in European Patent Application Publication No. 0708154 or Japanese Patent No. 54081337.

[0011] International Publication No. 2013 / 156327 shows a wet chemical production method in which a hydroxyl-containing metal oxide layer initially formed on a substrate of aluminum or an aluminum alloy is exposed to a liquid post-treatment medium at a temperature of at least 90 °C.

[0012] European Patent Application Publication No. 1553144 shows a red interference pigment based on Fe2O3 / SnO2 / [Al(P)] obtained by the wet chemical method. The pigment exhibits a higher chroma than pigments that do not contain an intermediate binder layer of hydrated tin oxide.

[0013] International Publication No. 2015 / 040537 shows a process of doping a metal oxide layer, especially an iron oxide layer, with aluminum. By adding a predetermined amount of another metal oxide in the metal oxide layer, the color characteristics and magnetic properties can be improved.

[0014] U.S. Patent Application Publication No. 2008 / 0249209 describes a method of surface - treating aluminum - based pigments with inorganic layers, hybrid (inorganic - organic) layers, and pure surface - functional molecules. The goal was to improve the application profile of the pigments, i.e., gas - generation stability and affinity with paint systems.

[0015] Aluminum - based pigments coated with iron oxide have specific safety issues due to the thermite reaction. Thus, various concepts exist to improve the safe handling of this material, such as by minimizing the aluminum content (U.S. Patent Application Publication No. 2019 / 0144679), by maximizing the aluminum content (U.S. Patent Application Publication No. 2007 / 0034112), or by mixing with non - reactive substances (International Publication No. 2013 / 175339).

[0016] Aluminum flakes are available in various qualities, which can be characterized by particle - size distribution (e.g., mean diameter d50 and spread of the particle - size curve (span)), color characteristics (e.g., brightness and hiding power), and surface area (BET). Typical values for non - VMP - type aluminum flakes are shown in Table 2. The basic principles of the characterization and production of aluminum flakes can be found in Wissling et al., Metalleffekt - Pigmente, 2nd Edition, 2013, Vincentz Network GmbH, or Metall - und Effektpigmnte fuer Lacke, Eckart, 1 / 2020 January 18CO, 099113XX0. For example, as described in Wissling et al., Metalleffekt - Pigmente, 2nd Edition, 2013, Vincentz Network GmbH, aluminum flakes can be produced by sublimation of the metal on a foil or by fine - grain ball - milling.

[0017] Aluminum pigments can be characterized by surface area BET, which is measured by gas adsorption and is known to those skilled in the art. BET relates to the average surface area according to the formula described in U.S. Patent Application Publication No. 2007 / 0034112 and is derived from simple mathematical / geometric considerations. The surface area, and therefore thickness, of ball-crushed metal flakes is characterized by the thickness distribution. In contrast, VMP-generating metal flakes exist in an extremely narrow thickness distribution. The surface area of ​​these thin VMP-generating flakes is mainly a result of the top and bottom surfaces of the flakes, and since the aspect ratio is high, the contribution of surface area from the sides is negligible.

[0018] The relationship between the bet and the average bet thickness can be expressed as follows:

[0019] [Table 1]

[0020] Aluminum pigments produced by fine-grain ball milling are well known to those skilled in the art (Wissling et al., Metaleffekt-Pigmente, 2nd edition, 2013, Vincentz Network GmbH). Here, the aluminum granules, milling parameters, and selection of milled balls are important variables that affect the color, lightness value, and opacity of the aluminum pigment.

[0021] However, existing coloring pigments are lacking in the mid-tone red range. For example, the saturation and / or brightness of existing pigments are insufficient for advanced applications that require improved color properties, such as those found in the automotive paint industry. The acquisition of new color spaces and good performance properties, such as opacity, appearance, and fastness (with respect to weather resistance and moisture resistance), can be achieved using pigments with high opacity, high saturation, and / or high brightness. There is a commercial interest in pigments with higher brightness and opacity in various applications, particularly in paint applications, and therefore there is a continuing demand for improved red effect pigments, especially those that stimulate the sense of color, in order to expand the available color space. [Prior art documents] [Patent Documents]

[0022] [Patent Document 1] International Publication No. 2015040537 [Patent Document 2] U.S. Patent Application Publication No. 20080249209 [Patent Document 3] International Publication No. 2013175339 [Patent Document 4] European Patent Application Publication No. 0033457 [Patent Document 5] European Patent Application Publication No. 0708154 [Patent Document 6] Japanese Patent No. 54081337 [Patent Document 7] International Publication No. 2013 / 156327 [Patent Document 8] European Patent Application Publication No. 1553144 [Patent Document 9] International Publication No. 2015 / 040537 [Patent Document 10] U.S. Patent Application Publication No. 2008 / 0249209 [Patent Document 11] U.S. Patent Application Publication No. 2019 / 0144679 [Patent Document 12] U.S. Patent Application Publication No. 2007 / 0034112 [Patent Document 13] International Publication No. 2013 / 175339 [Non-patent literature]

[0023] [Non-Patent Document 1] Wissling et al., Metal Effect-Pigmente, 2nd edition, 2013, Vincentz Network GmbH [Non-Patent Document 2] Metall- und Effektpigmnte fuer Lacke, Eckart, 1 / January 2020 18CO, 099113XX0 [Overview of the Initiative] [Problems that the invention aims to solve]

[0024] Therefore, an object of the present invention is to provide an intermediate red effect pigment having improved color characteristics, such as saturation and brightness, while maintaining good opacity. [Means for solving the problem]

[0025] The brightness of the metallic flakes describes their light-reflecting properties. For effect pigments, flakes are selected that are oriented towards the coating substrate and viewing angle. The application method is important.

[0026] To achieve this, those skilled in the art have found that the best-performing aluminum grade on the market has extremely high opacity and light reflectivity (i.e., high lightness value L). * Attempts would be made to find materials having 15). This would naturally lead to thin aluminum flakes with a high surface area, such as those produced by PVD. However, those skilled in the art would reject vacuum deposition pigments (VMPs) because they are difficult to process and not very stable (European Patent No. 2820089).

[0027] [Table 2]

[0028] Table 2 shows typical surface area BET, particle size distribution, and color values ​​(hue, saturation, lightness, opacity (ΣdE)) for non-VMP aluminum flakes. Typical lightness value for non-VMP aluminum flakes is lightness L. * 15 points is in the range of 150 to approximately 170.

[0029] The relationship between average thickness and opacity is recognized in Table 1. As shown, as the average thickness of the flakes increases, the opacity per gram of pigment per square meter increases. 2 This decreases significantly. Therefore, based on conventional knowledge, to improve the opacity of a pigment, those skilled in the art would typically use the thinnest metal flake with the highest surface area that they have at their disposal.

[0030] To achieve a better effect pigment with the best opacity in the intermediate red region, those skilled in the art can determine the highest opacity / m² per gram of pigment as shown in Table 1. 2 Therefore, VMP metal flakes would typically be used as the starting material for novel effect pigments. Given the simple method of manufacture and the brittleness of untreated or coated flakes, those skilled in the art would gravitate towards a lower-grade option—extremely thin aluminum flakes produced by ball grinding, which are readily available in large quantities and stable against mechanical forces in method and application testing. Thus, those skilled in the art would prefer high-surface-area aluminum (e.g., 6m) to obtain a desirable intermediate red color with high luminosity and opacity. 2 This will involve using extremely thin flakes produced by classic ball milling, with a weight of over 1g.

[0031] Surprisingly, contrary to common knowledge, according to the inventors, when coated with a passivation layer(s) and an absorbent layer such as Fe2O3, good opacity in the intermediate red range and excellent color properties are achieved with a surface area of ​​<6 m². 2 This is possible using aluminum flakes that exhibit a narrow particle size curve, good opacity, and high brightness.

[0032] A further object of the present invention is to provide a combination of pigments, including an intermediate red effect pigment, that has improved color characteristics (e.g., saturation and brightness) compared to conventional pigments while maintaining good opacity, particularly in orange to reddish paints for painting applications, and preferably in automotive paints.

[0033] The citation or identification of any document in this application does not admit that they represent prior art to the present invention.

Mode for Carrying Out the Invention

[0034] The present invention relates to an intermediate color red effect pigment having high chroma and high brightness at an angle of 15°, using a flaky metal substrate coated with a colored absorption layer containing iron oxide and / or iron oxide hydroxide (which may also contain other elements found in iron oxide layers, such as Mn, Si, Al, Ni). Optionally, the intermediate color red effect pigment can include a passivation layer between the metal substrate and the colored absorption layer.

[0035] Surprisingly, an equivalent hiding power and an even higher brightness factor (BF) with extremely good hiding power were found, which is contrary to the thinking of those skilled in the art regarding thicker aluminum flakes and thus a higher metal content in the final pigment.

[0036] Therefore, the present invention provides - h15 where 25° ≤ h15 ≤ 49°, preferably 28° ≤ h15 ≤ 45° - Chroma width (C * width) ≥ 60 - Lightness width (L * width) ≥ 90 - Brightness factor (BF) ≥ 140, more preferably brightness factor (BF) ≥ 145, most preferably brightness factor (BF) ≥ 150. In one embodiment, BF is 140 - 165 or 145 - 165 or 150 - 165 - Hiding power (ΣdE) < 110 - The aluminum metal content in the calculated dry pigment and the remainder calculated as oxides is 26% by mass or more and has an upper limit of 60% by mass - SiO2 content ≤ 10% by mass - The following combination of properties: ○ Specific surface area (BET) ≤ 4m 2 / g ○ Spread of particle size curve (span) ≤ 1.2 ○ Concealing force ΣdE < 20 ○ Lightness L * 15>153 Uses aluminum flakes This section lists intermediate red effect pigments, including [specific pigment name].

[0037] Furthermore, the present invention relates to a method for producing an intermediate red effect pigment.

[0038] Furthermore, the present invention relates to a method of using the above-mentioned intermediate red effect pigment for coloring compositions such as paints, printing inks, varnishes, plastics, fibers, thin films, or cosmetics. In another embodiment, the intermediate red effect pigment may be used to color automotive paint compositions, architectural paint compositions, and industrial coating compositions.

[0039] The term "intermediate red effect pigment" refers to an effect pigment having a reddish-orange color between 25° ≤ h15 ≤ 45°, as related to the drawdown method described in the following test methods section. The terms "thin flake" or "flake" refer to their substrates having an aspect ratio of 10:1 or greater.

[0040] Colors may be described in various color space systems. In this specification, color data C * (saturation), h (hue angle), L * (lightness), a * (Red-Green axis), and b * The (yellow-blue axis) is understood to be defined in the CIELAB color measurement system (as specified by the Commission Internationale de l'Eclairage). For example, considering point A in the CIELAB color space, it corresponds to three coordinates L. * a * , and b * Defined by CIELAB coordinate a * and b * As is known to those skilled in the art, cylindrical coordinate C * It can also be represented by h.

[0041] Metal oxide coated pigments are described not only by their individual color factors, but also by the lightness and chroma ranges between the face angle and downflop defined herein. Saturation width (C * Width):C * 15 minus C * 110 Lightness width (L * Width):L * 15 minus L * 110

[0042] C * 15, C * 110, L * 15, L * The value of 110 was measured using a BYK-mac i sensor 23mm, D65 light source 10° apparatus, while the color was applied with the described drawdown.

[0043] The objective of this invention is to achieve high absolute saturation (C) at the surface angle. * 15) High absolute brightness at the face angle (L * 15) The objective is to provide an intermediate red pigment having a wide saturation range and a wide lightness range. Since both saturation and lightness are involved in the optical identification of the pigment, they can be combined into a single factor called the luminance factor (BF), which is given by the following formula: Luminance factor (BF) = Saturation range + Brightness range As shown, it is determined as the sum of the saturation range and the brightness range.

[0044] An additional objective of the present invention is to maximize the luminance factor (BF).

[0045] Another objective of the present invention is to maintain an opacity of less than ΣdE = 110, which is preferable in automotive painting.

[0046] The metal substrate may be a wide range of metals used in the field of effect pigments. The metal substrate is usually in the form of flakes or flaks. The metal substrate can be selected from aluminum, steel, silver, copper, gold-bronze (brass), zinc, zirconium, tin, titanium, their alloys, and combinations thereof. The metal substrate is preferably aluminum-based, iron, copper, or gold-bronze.

[0047] More preferably, the metal substrate is an aluminum-based substrate. Suitable aluminum-based substrate particles are generally known to those skilled in the art. The aluminum-based substrate particles can be made from an aluminum core or an aluminum alloy core, which can be at least partially coated with one or more passivation layers.

[0048] Thin sheets or flakes of aluminum or aluminum alloys can be obtained by general spraying and grinding techniques. Suitable thin sheets of aluminum or aluminum alloys are produced, for example, by the Hall method of wet grinding in volatile oil. The starting material is powdered, irregular, coarse aluminum grains, which are ball-ground into flaky particles in volatile oil and in the presence of a lubricant, and then sorted. Dry grinding of aluminum powder is also possible.

[0049] The metal substrate is more preferably aluminum. Depending on the quality and shape of the initial fine particles and the grinding conditions, the aluminum substrate may be of the "cornflake" type, "silver dollar" type, or even "platin dollar" type.

[0050] The surface area of ​​the product is defined, and the average thickness of a large quantity of flakes is stated, but the individual thickness of each aluminum flake can vary and can be determined by cross-sectional TEM / SEM. Typically, the geometric thickness of metal flakes, in particular aluminum-based flakes, may be in the range of 10 nm to 1500 nm, preferably 10 to 1000 nm, more preferably 20 to 800 nm, and most preferably 20 to 700 nm.

[0051] The average diameter of the thin film, particularly the aluminum or aluminum alloy thin film, may be in the range of 3 to 100 μm, preferably 5 to 50 μm. Typically, the aspect ratio of the average diameter to the average thickness may be in the range of 10:1 to 1000:1. The diameter can be determined by laser scattering size measurement.

[0052] As described above, the aluminum or aluminum alloy core of the aluminum-based substrate particles may be at least partially covered with one or more passivation layers, or for example, completely covered with one or more passivation layers. Preferably, one or more passivation layers completely cover the aluminum-based flake, including the sides.

[0053] Suitable passivation layers are generally known to those skilled in the art. The passivation layer is preferably an inorganic layer, such as a metal phosphate layer or an inorganic oxide layer. When the inorganic passivation layer is a metal phosphate layer, the metal may be selected from Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Al, Zr, Nb, Mo, Ta, or W. When the inorganic passivation layer is an inorganic oxide layer, the oxide may be selected from Ti oxide, V oxide, Cr oxide, Mn oxide, Fe oxide, Co oxide, Ni oxide, Cu oxide, Zn oxide, Al oxide, Zr oxide, Nb oxide, Mo oxide, Ta oxide, W oxide, Ge oxide, Si oxide, Sn oxide, and Bi oxide, or any combination thereof.

[0054] Preferably, the passivation layer is a metal phosphate layer, a silica layer, an aluminum oxide layer, an aluminum hydroxide (AlOOH) layer, or a combination thereof. More preferably, the passivation layer is a silica layer and an Al oxide layer.

[0055] In one preferred embodiment, the present invention relates to an intermediate red effect pigment, wherein the effect pigment comprises an aluminum substrate passivated with a layer of metal phosphate, silica, aluminum oxide, aluminum hydroxide, or a combination thereof.

[0056] According to the present invention, the iron oxide layer is applied to an optionally passivated flaky metal substrate, preferably an optionally passivated aluminum-based flaky substrate. The iron oxide layer can be produced by the following wet chemical method. The wet chemical coating method is generally carried out until the desired interference color is obtained. Heat treatment transfers the hydroxyl-containing iron oxide layer to the Fe2O3-containing layer. The desired final hue h15 after heat treatment is 25°≦h15≦49°, preferably 28°≦h15≦45°.

[0057] Preferably, the optionally passivated metal flake substrate is completely encapsulated by an iron oxide layer.

[0058] For example, the geometric thickness of an iron oxide coating obtained by a wet chemical process is typically about 120 to 500 nm, preferably 130 to 450 nm, and more preferably 150 to 350 nm. The geometric layer thickness can be determined based on TEM micrographs (cross-sectional views).

[0059] To obtain the desired effect pigment, various layers of silicon dioxide or iron oxide may be applied, for example. Preferably, the intermediate red effect pigment has only one iron oxide layer. More preferably, the intermediate red effect pigment does not have any further metal oxide layers with a high refractive index.

[0060] The iron oxide layer may contain up to 20% by mass of other metals, such as aluminum, silicon, or zirconium, relative to the total amount of iron metal atoms in the iron oxide layer. The doping metal concentration in the iron oxide layer can be determined, for example, by TEM combined with EDXS (energy-dispersive X-ray spectroscopy), as referred to in International Publication No. 2015 / 040537.

[0061] Preferably, the iron oxide layer can be doped with up to 10% by mass of aluminum relative to the total amount of iron and aluminum atoms in the aluminum-doped iron oxide layer. Preferably, the aluminum-doped iron oxide layer contains 0.05% to 10% by mass, or 0.5 to 8% by mass, or 0.5 to 6% by mass of Al, relative to the total amount of Fe and Al atoms in the Al-doped iron oxide layer.

[0062] Typically, the Al concentration in the Al-doped iron oxide layer near the substrate is higher than the Al concentration in the Al-doped iron oxide layer further away from the substrate.

[0063] In another embodiment, the iron oxide layer may contain other elements in addition to aluminum, such as silicon. This can be incorporated during or at a later stage of the iron oxide hydroxide coating process. Preferably, the iron oxide layer may be doped with silicon up to 15% by mass relative to the total amount of iron atoms in the iron oxide layer. Preferably, the iron oxide layer contains 0.05% to 15% by mass, or 0.5 to 10% by mass, or 0.8 to 8% by mass of Si relative to the total amount of Fe and Si atoms in the iron oxide layer.

[0064] In the present invention, the iron oxide layer may correspond to the outermost layer of the intermediate red effect pigment. Alternatively, one or more additional layers, such as an SiO2 layer, a polymer layer, an organosilane layer, or any combination thereof, may be applied to the iron oxide layer.

[0065] The geometric thickness of the final layer may be 2 to about 50 nm, preferably 2 to 30 nm, and more preferably 2 to 20 nm, depending on the type of surface modification.

[0066] In a preferred embodiment, the intermediate red effect pigment includes a final layer selected from an SiO2 layer, a polymer layer, an organosilane layer, or a combination thereof. The term “final layer” is synonymous with “outermost layer.” Such surface modifications are typically tailored to a specific end application. These final layers can be used to adjust the surface polarity of the intermediate red effect pigment, thereby improving the adhesion of the effect pigment to a binder system, such as a paint or ink.

[0067] Methods for surface modification of effect pigments and suitable surface modifiers, such as silanes having surface-reactive functional groups (e.g., alkoxysilanes), are known to those skilled in the art and can improve the affinity between effect pigments and varnishes or lacquers. Surface modification methods and surface modifiers are described, for example, in European Patent Publication No. 1682622, European Patent Publication No. 1904587, International Publication No. 99 / 57204, European Patent Publication No. 1812519, or European Patent Publication No. 0688833.

[0068] Intermediate red effect pigments can be produced by coating an optionally passivated flaky metal substrate with a wet chemical process, which involves the hydrolysis of iron(III) salts in a liquid medium.

[0069] Therefore, a further aspect of the present invention is a method for producing an intermediate red effect pigment as described in any aspect of this specification, (a) A step of preparing a passivated thin metal substrate, and (b) A step of coating a substrate in a liquid medium containing an iron oxide precursor compound. This includes methods.

[0070] Preferably, the intermediate red effect pigment obtained by the method of the present invention, or the intermediate red effect pigment that can be obtained by the method of the present invention, corresponds to the intermediate red effect pigment described herein.

[0071] Methods for producing a passivation layer on a metal substrate such as an aluminum flake are generally known to those skilled in the art.

[0072] In this specification, the term “iron oxide” means in particular α-iron(III) oxide. However, the term “iron oxide” also includes mixtures of α-iron(III) oxide and small amounts of γ-iron(III) oxide, magnetite (Fe3O4), hydrated iron oxide or iron oxide hydroxide (e.g., FeO(OH), Fe2O3·H2O, Fe2O3·nH2O of n≧2, Fe(OH)3, Fe(OH)2, or mixtures of two or more of these hydroxyl-containing iron oxides). Preferably, the Fe atom exists as Fe(III). However, within the present invention, the Fe atom may exist as Fe(II). Preferably, the iron oxide layer contains Fe2O3.

[0073] Aluminum metal reacts rapidly with air until a thin shell of aluminum oxide is formed. This process, called passivation, results in a thin layer of aluminum oxide (Al2O3) on the surface of the metal.

[0074] The terms “the mixture” or “the combination” mean any possible physically blended mixture or combination of two or more components, either of the same or different types, as mentioned in each list.

[0075] The layer thickness is typically generated from cross-sectional views of approximately 10 to 50 flakes and determined by transmission electron microscopy (TEM) or scanning electron microscopy (SEM). As described in U.S. Patent No. 11292917, a thin film of a coating containing aligned flakes is cut and analyzed by SEM or TEM, and the geometric thickness values ​​of approximately 10 to 50 flakes are examined and statistically averaged. Preferably, more than 20 different points are measured to obtain the average number. Depending on the desired method, various layer thicknesses may be required. Intermediate red pigments from chemical vapor deposition are known to exist in a layer of approximately 120 nm (Ostertag, W. (1994), Effektpigmente.Nachr.Chem.Tech.Lab.42:pp. 849-854, https: / / doi.org / 10.1002 / nadc.19940420907), while wet chemical layers include thicker layers and reach this color space.

[0076] In a wet chemical process, suitable precursor compounds, such as organosilicon compounds and / or organoaluminum compounds in which an organic group is bonded to a metal via an oxygen atom, are typically hydrolyzed in the presence of substrate particles (e.g., aluminum flakes or aluminum flaks) and an organic solvent in which the metal compound is soluble. Preferably, metal alkoxides (particularly tetraethoxysilane and aluminum triisopropoxide) are hydrolyzed with water in the presence of an alcohol (e.g., ethanol or 2-propanol) and a basic catalyst and / or an acid catalyst. The basic catalyst may be, for example, aqueous ammonia and / or aqueous amine solution, and the acid catalyst may be, for example, phosphoric acid or an organic acid, such as acetic acid or oxalic acid. This is preferably carried out by first filling the mixture with substrate particles, ethanol, water, and ammonia, and heating the mixture to 40°C to 90°C while stirring and continuously adding the metal alkoxide solution in ethanol and water or aqueous ammonia solution. Subsequently, after a stirring time of typically 1 to 15 hours, the mixture is cooled to room temperature, and the coated pigment is isolated by filtration, washing, and optionally drying. Further details on the method for producing a passivation layer on aluminum are provided, for example, in European Patent Application Publication No. 0708154, German Patent Application Publication No. 4405492, or International Publication 2011 / 95341.

[0077] The iron oxide layer is typically produced by a wet chemical process, for example, by hydrolysis of a suitable iron oxide precursor compound. The coating process is generally carried out until the desired interference color is obtained. Heat treatment transfers the hydroxyl-containing iron oxide layer to the Fe2O3-containing layer, preferably the hematite layer.

[0078] As described above, the substrate is coated in a liquid medium containing an iron oxide precursor compound. Typically, the liquid medium is an aqueous medium containing 10-100% by mass or 30-100% by mass of water relative to the total amount of liquid in the aqueous medium.

[0079] Iron oxide precursor compounds that can be used to yield an iron oxide layer by wet chemical processes are generally known to those skilled in the art. Exemplary iron oxide precursor compounds include, for example, iron salts such as iron(III) halides (e.g., FeCl3), iron(III) nitrate, and iron(III) sulfate, hydrolyzable iron compounds such as iron alkoxides, iron complex compounds such as iron acetylacetonate, or any combination or mixture thereof.

[0080] In principle, the iron oxide layer can be applied to the substrate at an acidic or basic pH. Preferably, the liquid medium has a pH of 5 or less, more preferably 4 to 2. Preferably, the pH of the aqueous medium is kept constant while the iron oxide layer or Al-doped iron oxide layer is applied to the substrate. The temperature can vary over a wide range, for example, from at least 20 to 100°C.

[0081] Preferably, the resulting pigment is subsequently subjected to a heat treatment step, such as a step of drying the pigment and / or a step of carrying out further condensation in the iron oxide layer. The heat treatment step may be carried out by calcination at about 250 to 450°C, preferably 280 to 400°C, for at least 5 minutes, for example, about 10 to 60 minutes. Alternatively, the resulting effect pigment may be exposed to a medium containing one or more high-boiling point solvents and heated at a temperature of at least 90°C for at least 0.5 hours.

[0082] High-boiling point solvents typically have a boiling point of 90 to 400°C, more preferably 100 to 300°C. Examples include monohydroxy alcohols, diols or polyols, glycol ethers, polyglycol ethers, polyethylene glycol monoethyl ethers, polypropylene glycols, aldehydes, esters, carbonate esters, organic acids, amides, lactams (e.g., NMPs), ketones, ethers, alkanes, halide-substituted alkanes, aromatic compounds, liquid polymers, mineral oils, or mixtures thereof.

[0083] Typically, intermediate red effect pigments are isolated, sometimes combined, by known methods such as filtration or heat treatment, and used as a paste.

[0084] Therefore, in a further embodiment, the present invention is (a) A step of preparing a passivated thin metal substrate, and (b) A step of coating a substrate in a liquid medium containing an iron oxide precursor compound. This specification relates to intermediate red effect pigments, which can be obtained by methods including the aforementioned.

[0085] For various applications, the intermediate red effect pigment can be used preferably in blends with any further pigment, preferably a color-absorbing pigment, and optionally with conventional effect pigments different from the intermediate red effect pigment of the present invention, to provide a combination of pigments.

[0086] The pigment combination of the present invention comprises at least two or three components, wherein the effect pigment (a) is an intermediate red effect pigment as defined herein, the second pigment (b) is at least one color absorption pigment, and the optional third pigment (c) is a further effect pigment.

[0087] In general, pigment (b) may be at least one pigment other than an effect pigment or a white pigment. Pigment (b) may be a pigment having any of the following tones, preferably a yellow tone, a reddish tone, or a greenish tone. Combinations with other coloring pigments, such as a black pigment or a brown pigment, are also possible to achieve the effect.

[0088] Preferably, the colored absorbing pigment (b) is a transparent colored absorbing pigment in any shade ranging from green to yellow, violet, or even blue, depending on the application, preferably the desired shade of the desired coating. Combinations with other colored pigments, such as black or brown pigments, e.g., transparent carbon black pigment or transparent black perylene pigment, are also possible.

[0089] In this specification, the term “transparent pigment” means a pigment that provides a coating that is substantially transparent in the range of 400–700 nm, except for the perceptible scattering of radiation at its wavelength.

[0090] Pigment (b) may be an organic pigment, an inorganic pigment, or a mixture thereof. Preferably, pigment (b) has a color suitable for imparting a hue such as yellow, red, or green to the effect pigment of the present invention.

[0091] Therefore, in a preferred embodiment, pigment (b) is at least one transparent pigment selected from the group consisting of organic pigments, inorganic pigments, and mixtures thereof.

[0092] Suitable organic colored absorbent pigments for the pigment combinations of the present invention typically include organic colored pigments and black pigments. Suitable examples include pigments selected from the group consisting of monoazo, disazo, disazo condensation, antantrone, anthraquinone, anthrapyrimidine, benzimimidazolone, quinacridone, quinophthalone, diketopyrrolopyrrole, dithioketopyrrolopyrrole, dioxazine, flavanthrone, indanthrone, isoindoline, isoindolinone, isobiolantrone, metal complexes, perinone, perylene, phthalocyanine, pyrantrone, pyrazoloquinazolone, indigo, thioindigo, triarylcarbonium pigments, and mixtures thereof, including solid solutions or mixed crystals thereof.

[0093] Suitable examples include: • Monoazo pigments: CI Pigment Yellow 1, 3, 62, 65, 73, 74, 97, 183, and 191; CI Pigment Orange 5, 38, and 64; CI Pigment Red 1, 2, 3, 4, 5, 23, 48:1, 48:2, 48:3, 48:4, 49, 49:1, 51, 51:1, 52:1, 52:2, 53, 53:1, 53:3, 57:1, 58:2, 58:4, 63, 112, 146, 148, 170, 184, 187, 191:1, 210, 245, 247, and 251, • Disazo pigments: CI Pigment Yellow 12, 13, 14, 16, 17, 81, 83, 106, 113, 126, 127, 155, 170, 174, 176, and 188; CI Pigment Orange 16, 34, and 44, • Disazo condensation pigments: CI Pigment Yellow 93, 95, and 128; CI Pigment Red 144, 166, 214, 220, 221, 242, and 262; CI Pigment Brown 23 and 41, • Antantron pigment: CI Pigment Red 168 • Anthraquinone pigments: CI Pigment Yellow 147 and 199; CI Pigment Red 177, • Anthrapyrimidine pigment: CI Pigment Yellow 108 • Benzimidazolone pigments: CI Pigment Yellow 120, 151, 154, 180, 181; CI Pigment Orange 36 and 72; CI Pigment Red 175, 185, 208; CI Pigment Violet 32; CI Pigment Brown 25, • Quinacridone pigments: CI Pigment Orange 48 and 49; CI Pigment Red 122, 202, 206, and 209; CI Pigment Violet 19, • Quinophthalone pigment: CI Pigment Yellow 138 • Diketopyrrolopyrrole pigments: CI Pigment Orange 71, 73, and 81; CI Pigment Red 254, 255, 264, 270, and 272, • Dioxazine pigments: CI Pigment Violet 23 and 37, • Flavantron pigment: CI Pigment Yellow 24 • Indanthron pigments: CI Pigment Blue 60 and 64 • Isoindoline pigments: CI Pigment Yellow 139 and 185; CI Pigment Orange 61 and 69, CI Pigment Red 260, • Isoindolinone pigments: Isoindolinone pigments: CI Pigment Yellow 109, 110, and 173; Pigment Orange 61, • Isobiolantron pigment: CI Pigment Violet 31 • Metal complex pigments: CI Pigment Red 257; CI Pigment Yellow 117, 129, 150, 153, and 177; CI Pigment Green 8, • Perinon pigments: CI Pigment Orange 43; CI Pigment Red 194 • Perylene pigments: CI Pigment Red 123, 149, 178, 179, and 224; CI Pigment Violet 29, • Phthalocyanine pigments: CI Pigment Blue 15, 15:1, 15:2, 15:3, 15:4, 15:6, 16 CI Pigment Green 7, 36 • Pyrantron pigments: CI Pigment Orange 51; CI Pigment Red 216 • Pyrazoloquinazolone pigments: CI Pigment Orange 67 and CI Pigment Red 216 • Indigo pigment: CI Pigment Red 282 • Thioindigo pigments: CI Pigment Red 88 and 181; CI Pigment Violet 38, • Triarylcarbonium pigments: CI Pigment Red 81, 81:1, and 169; CI Pigment Violet 1, 2, 3, and 27; CI Pigment Blue 1, 61, and 62; CI Pigment Green 1, • CI Pigment Yellow 101 (Aldazine Yellow) CI Pigment Brown 22.

[0094] Preferably, the organic pigment is a yellow, green, blue, red, or orange organic pigment selected from any mixture including yellow to reddish, green, or blue organic pigments, such as anthraquinone, diketopyrrolopyrrole, isoindolinone, metal complexes, perinone, perylene, phthalocyanine pigments, indigo pigments, or solid solutions or mixed crystals, i.e., CI pigment green, CI pigment yellow, CI pigment red, or CI pigment orange.

[0095] Particularly preferred are CI Pigment Yellow 129, Pigment Yellow 110, Pigment Red 168, Pigment Red 177, Pigment Red 179, Pigment Red 282, and any of the diketopyrrolopyrrole pigments, such as Pigment Orange 71, Pigment Orange 73, Pigment Red 254, Pigment Red 255, Pigment Red 264, Pigment Red 272, or Pigment Red 291.

[0096] Suitable organic pigments are commercially available under the trademarks Irgazin® Cosmoray Orange L2950, ​​Irgazin® Rubine L4025, Irgazin® Rubine L4030, Irgazin® Orange L2990HD or Irgazin® Orange D2905, Irgazin® Red L3630, Irgazin® Yellow L2040, Irgazin® Yellow L0800, Paliogen® Red L3885, Paliogen Red L3920, Heliogen® Blue L6950, or Heliogen Green L9361.

[0097] Suitable inorganic pigments may be transparent yellow iron oxide pigment (CI Pigment Yellow 42), transparent red iron oxide pigment (CI Pigment Red 101), or mixtures thereof.

[0098] Suitable inorganic black or inorganic brown pigments may be carbon black (CI Pigment Black 7), graphite (CI Pigment Black 10), or chromium iron oxide (CI Pigment Brown 29).

[0099] Suitable inorganic pigments are commercially available, for example, under the trademark Sicotrans®.

[0100] The colored absorbing pigment (b) is preferably transparent.

[0101] The effect pigment (c) may be any conventional effect pigment known in the art. The effect pigment (c) may be a metallic pigment such as aluminum flakes, or an effect pigment based on a transparent substrate such as natural mica, synthetic mica, or glass flakes. The transparent substrate is typically coated with one or more layers of metal oxides such as TiO2, TiO2 (doped with SnO2), SiO2, and / or Fe2O3. Preferred are pigments that reflect gold to red light due to interference and absorption phenomena of the thin film. Thus, the intermediate red metallic luster of the opaque intermediate red effect pigment of the present invention can be modified, in particular, using a semi-transparent pigment of a similar color. The color effect is a richness of metallic luster with so-called depth in three dimensions (two dimensions).

[0102] Suitable effect pigments (c) are commercially available, for example, under the trademarks Lumina® or Mearlin®.

[0103] The mass ratio of the intermediate red effect pigment (a) to the colored absorbent pigment (b) and any effect pigment (c) can vary over a wide range.

[0104] In a further embodiment, the present invention is (a) an intermediate red effect pigment comprising an optionally passivated flake metal substrate and an iron oxide layer, wherein the effect pigment has a hue angle h15 of 25°≦h15≦45° and (b) Colored absorbent pigments and (c) Optionally, further effect pigments and A combination of pigments including, The mass ratio of the gold effect pigment (a) to pigments (b) and (c) is 95:5 to 5:95, preferably 80:20 to 5:95, and more preferably 75:25 to 20:80. Regarding pigment combinations.

[0105] The mass ratio of the intermediate red effect pigment (a) to pigment (b) and any pigment (c) is, for example, 95:5, meaning that 95% by mass corresponds to the intermediate red effect pigment and 5% by mass corresponds to the combination of pigment (b) and pigment (c). The mass ratio of pigment (b) to pigment (c) may be 100:0 to 50:50, preferably 75:25 to 60:40.

[0106] Preferably, pigment (b) is a transparent pigment selected from the group consisting of organic pigments, inorganic pigments, and mixtures thereof.

[0107] In particular, the organic pigments are reddish organic pigments, such as reddish, green, or blue organic pigments, selected from any mixture thereof, including anthraquinone, diketopyrrolopyrrole, isoindolinone, metal complexes, perinone, perylene, phthalocyanine, indigo pigment, or solid solutions or mixed crystals.

[0108] The inorganic pigment may be a transparent yellow iron oxide pigment (CI Pigment Yellow 42), a transparent red iron oxide pigment (CI Pigment Red 101), or a mixture thereof.

[0109] Pigment (c) may be an effect pigment selected from metal pigments, or an effect pigment based on a transparent substrate selected from natural mica, synthetic mica, or glass. Preferably, pigment (c) comprises a flaky substrate selected from natural mica, synthetic mica, or glass, which is coated with one or more layers of metal oxides selected from TiO2, TiO2 (doped with SnO2), SiO2, and / or Fe2O3.

[0110] The metallic pigment may be an aluminum-based flake, preferably an aluminum flake.

[0111] The intermediate red effect pigment (a) may be incorporated into a conventional application system, for example, as a slurry or paste.

[0112] Therefore, the present invention provides a composition comprising an intermediate red effect pigment.

[0113] Pigment combinations can be incorporated into conventional application systems. The intermediate red effect pigment (a) defined herein may be added as a slurry, as with any effect pigment (c). Typically, pigment (b) is added in a pre-dispersed state.

[0114] The effect pigments or combinations of pigments of the present invention are applicable to all end uses of pigments, particularly for coloring naturally occurring and synthetically derived organic or inorganic materials, for example, a) For example, coloring polymers in the form of resins, rubbers, or plastics including thin films and fibers, b) For example, the manufacture of paints, coating systems, and coating compositions in automotive coating compositions, architectural coating compositions, and industrial coating compositions. c) Ink, printing ink, e.g., toner for digital printing such as inkjet printing, and toner for electrophotography, e.g., laser printers, d) Colorants, for example, as additives to pigments and dyes, e) Cosmetics It is particularly suitable for the following purposes.

[0115] The coating is an aqueous or solvent-based coating material, and combinations of pigments of the present invention may be used. Organic thin-film forming binders that can be used include all binders commonly used in the coating field. Examples of binder materials that can be colored with gold-effect pigments or combinations of pigments defined herein include, in more detail, • Oil-based materials (based on linseed oil or polyurethane oil) • Cellulose-based materials (NC, CAB, CAP) • Materials based on chlorinated rubber • Vinyl materials (based on PVC, PVDF, VC copolymer, polyvinyl acetate, polyvinyl ester dispersion, polyvinyl alcohol, polyvinyl acetal, polyvinyl ether, polystyrene, and styrene copolymer) • Acrylic materials • Alkyd materials • Saturated polyester material • Unsaturated polyester material • Polyurethane material (1 pack, 2 packs) Epoxy materials • Silicone materials These are some examples.

[0116] This system is described in detail in D. Stoye and W. Freitag, Paints, Coatings and Solvents, 2nd edition, 1998, Wiley-VCH.

[0117] Preferably, the intermediate red effect pigment or the combination of pigments of the present invention is used in aqueous and solvent-based coating applications, more preferably in decorative coating compositions such as architectural coating compositions, automotive coating compositions, or industrial coating compositions for any consumer goods.

[0118] Intermediate red effect pigments or combinations of pigments of the present invention are generally incorporated into their respective application media in conventional ways. Molded articles may be coated with these application media and thus colored. The molded articles may be, for example, car bodies, industrial equipment, exterior materials, etc.

[0119] In the case of plastics, the intermediate red effect pigment or the pigment combination of the present invention may be incorporated in large quantities into the application medium for coloring. The molded article contains the intermediate red effect pigment or the pigment combination of the present invention.

[0120] Suitable compositions for cosmetics into which intermediate red effect pigments may be introduced are known in the art. The formulation of cosmetics using the intermediate red effect pigment of the present invention can be achieved by means and methods well known to those skilled in the art. Intermediate red effect pigments or combinations of pigments of the present invention can be appropriately used, for example, in nail polish.

[0121] In a further embodiment, the present invention relates to a method for using an intermediate red effect pigment or combination of pigments, as defined in any embodiment herein, for coloring or shaping a coating composition, such as a paint, printing ink, ink, varnish, plastic, fiber, thin film, or cosmetic, preferably an automotive coating composition, a building coating composition, or an industrial coating composition.

[0122] The coating composition may be any decorative coating composition such as an automotive coating composition, a building coating composition, or an industrial coating composition, or a paint. The coating composition, printing ink, ink, or paint may be aqueous or solvent-based. Preferably, the intermediate red effect pigment or the combination of pigments of the present invention is used as a colorant for automotive coating compositions, building coating compositions, industrial coating compositions, paints, printing inks, inks, or plastics. In particular, the intermediate red effect pigment or the combination of pigments of the present invention is used as a colorant for OEM vehicle coating compositions or refinish coating compositions.

[0123] In a further embodiment, the present invention relates to a coating composition comprising a paint, printing ink, ink, varnish, plastic, fiber, thin film, or cosmetic, which is colored or chromated using an intermediate red effect pigment or combination of pigments as defined in any embodiment herein.

[0124] In a further embodiment, the present invention relates to a molded article coated with a composition comprising an intermediate red effect pigment or combination of pigments as defined in any embodiment herein.

[0125] Any material of a molded article, including materials such as glass, ceramics, plastics, smooth-surface composites, and metal substrates, may be coated with a composition comprising an intermediate red effect pigment or a combination of pigments of the present invention. In particular, the composition is especially suitable for metal or plastic molded articles. The molded article may be a bare substrate material, or, in the case of a metal substrate, may be manufactured to impart corrosion resistance by electrodeposition such as phosphate chlorination or cathode dipping coating, or other similar treatments well known in the art.

[0126] Coatings containing intermediate red effect pigments or combinations of pigments of the present invention are particularly suitable for multi-layer coatings used in the automotive industry. Intermediate red effect pigments or combinations of pigments of the present invention are typically incorporated into the base coat layer of base coat / clear coat coating systems known in the art.

[0127] Accordingly, the present invention relates to automotive paints that are colored or painted with intermediate red effect pigments or combinations of pigments as defined in any embodiment herein.

[0128] In a further embodiment, the present invention relates to a method for coloring or shaping a coating composition, such as a paint, printing ink, ink, varnish, plastic, fiber, thin film, or cosmetic, preferably an automotive coating composition, a building coating composition, or an industrial coating composition, comprising the step of adding an intermediate red effect pigment or a combination of pigments as defined herein to the coating composition.

[0129] The present invention is further described by the following set of embodiments and combinations of embodiments, which are derived from the given dependent claims and backreferences. In particular, note that in each instance where the scope of an embodiment is referred to, in the context of terms such as "any one of Embodiments 1 to 5," all embodiments within this scope are clearly disclosed to those skilled in the art. That is, this wording is understood by those skilled in the art to be synonymous with "any one of Embodiments 1, 2, 3, 4, and 5." Furthermore, it is noted that the following set of embodiments, while not a set of claims determining the scope of protection, represent a well-structured portion of the overall aspects of the invention and descriptions of specific aspects.

[0130] 1. A plate-shaped metal core and A silicon-containing passivation layer, Iron oxide-containing layer on the upper surface of the passivation layer and A mid-tone red effect pigment, which includes, h15 is in the range of 25° ≤ h15 ≤ 49°, preferably 28° ≤ h15 ≤ 45°. BF is 140-165, preferably 145-165, most preferably 150-165. The concealing power is ΣdE < 110. Intermediate red effect pigment.

[0131] 2. The plate-shaped metal core has the following characteristics: a. Surface area (BET)≦4m 2 / g, preferably with a surface area (BET) ≤ 3.8m² 2 / g, more preferably surface area (BET) ≤ 3.5m²2 / g, b. Spread (span) of the particle size curve ≤ 1.2, preferably ≤ 1.1. c. Concealing force ΣdE < 20, preferably concealing force ΣdE < 15, more preferably concealing force ΣdE < 13, d. Lightness L * 15 > 153, preferably lightness L * 15>155 A pigment of Embodiment 1 comprising aluminum flakes having [a certain characteristic].

[0132] 3. The pigment of Embodiment 1, wherein the metal content is 25-60% by mass, preferably 25-40% by mass, and most preferably 25-38% by mass.

[0133] 4. The pigment of Embodiment 1, having a saturation range of 60 or more.

[0134] 5. The pigment of Embodiment 1, having a lightness range of 90 or more.

[0135] 6. A pigment according to any of Embodiments 1 to 5, wherein the average particle size d50 is 16 μm or larger.

[0136] 7. A pigment according to any one of Embodiments 1 to 6, wherein the iron oxide layer contains 10% by mass or less of each of the other metal ions.

[0137] 8. A pigment according to any of Embodiments 1 to 7, comprising one or more additional layers applied on an iron oxide layer.

[0138] 9. A pigment according to any of Embodiments 1 to 8, wherein the iron oxide layer has an average thickness of 150 to 350 nm.

[0139] 10. A pigment according to any one of Embodiments 1 to 9, wherein the pigment comprises one or more additional layers on an iron oxide layer, selected from the group consisting of a silica layer, an organosilane layer, a polymer layer, or a combination thereof.

[0140] 11. The pigment of Embodiment 10, wherein the additional layer contains SiO2 in an amount of 10% by mass or less.

[0141] 12. A method for producing one or more intermediate red effect pigments, according to any one of Embodiments 1 to 9, wherein aluminum flakes are produced by a ball milling method. [Examples]

[0142] The present invention is further described by the following non-limiting examples, which do not intend to further illustrate the present invention or limit its scope, nor should they be described in a way that limits its scope.

[0143] Measurement test method Concealing power ΣdE: (Drawdown method for concealing power) 0.044 g of a dry aluminum substrate or, for example, 0.088 g of a dry coating compound having an iron oxide layer was added to 4 g of lacquer (87 parts ZM26-3025 Colorclassic plus 13 parts ZC15-100E CAB solution, adjusted to 36 parts DIN4 with xylol / butyl acetate (30:70)) and mixed at 3000 rpm for 1 minute in a 25 mL SpeedMixer vial of a Hauschild SpeedMixer DAC150.1FVZ-K. The mixture was immediately coated onto a Leneta Form14H opacity chart black / white using an Eriksen Coat Master 510 thin film coating apparatus with Eriksen Knochenrakel Model 125 μm at room temperature = 21°C and a speed of 18 mm / sec. The Leneta opacity chart was fixed in place on the Eriksen Coat Master by using its upper vacuum suction plate. The chart was dried in a draft at room temperature (21°C) for two days, and then measurements were taken using a multi-angle color and effect measuring device, BYK-mac i sensor 23mm, and D65 light source 10°, with five measurements taken for each section, in black and white. The opacity was calculated as ΣdE=dE(15°)+dE(25°)+dE(45°)+dE(75°)+dE(110°).

[0144] BET: Approximately 1.5–2.0 g of the dry, solvent-free product is packed into a 9 mm cuvette sample holder of the Quantachrome Nova4000e surface area analyzer. The exact sample volume is determined by weighing an empty cuvette at room temperature, heating a filled cuvette under vacuum to 100°C for 30 minutes, and weighing it again at the same room temperature. Five-point measurements are then performed in nitrogen at the analysis station of the Quantachrome instrument, at relative pressures P / Po 0.10 / 0.15 / 0.20 / 0.25 and 0.30. The BET value is automatically calculated by the instrument in units m 2 It is given by / g.

[0145] Particle size: The sample is pre-dispersed in isopropanol before being placed in the Hydro MV measurement cell of the Panalytical Malvern Mastersizer 3000. Measurements are performed for aluminum substrates in isopropanol at US 30% for 10 minutes, and for coated compounds having, for example, an iron oxide layer, in isopropanol at US 10% for 2 minutes. Based on these measurements, the average particle size d50 and the spread of the distribution curve, described herein as the particle size distribution span = (d90-d10) / d50, can be determined. Typical d50 values ​​used are in the range of d50 = 5 to 50 μm, more preferably 8 to 30 μm for automotive coatings, and even more preferably 9 to 25 μm.

[0146] Hue, saturation, and lightness: (Drawdown method for hue, saturation, and lightness) 0.88 g of dry pigment was added to 4 g of lacquer (87 parts ZM26-3025 Colorclassic plus 13 parts ZC15-100E CAB solution, adjusted to 36 parts DIN4 with xylol / butyl acetate (30:70)) and mixed at 3000 rpm for 1 minute in a 25 mL SpeedMixer vial of a Hauschild SpeedMixer DAC150.1FVZ-K. The mixture was immediately coated onto BYK Bikochart plain white WH2828 using an Erichsen Coat Master 510 thin film coating apparatus with Erichsen Knochenrakel Model 125 μm at room temperature (21°C) and a speed of 18 mm / sec. The BYK Bikochart was fixed in place on the Erichsen Coat Master by using its upper vacuum suction plate. The chart is dried in a fume hood at room temperature (21°C) for two days, and then measurements are taken at five points spread across the middle portion of the thin film coating using a multi-angle color and effect measurement device, the BYK-mac i sensor (23mm) and D65 light source (10°).

[0147] Chemical analysis: The amounts of the elements Al, Si, Fe, and Sn in grams per 100g of dry pigment are measured using an Agilent ICP-OES Model 5100. The amounts of oxides, SiO2, Fe2O3, and SnO2, are calculated using the molar mass M and mass m as follows: m(SiO2) = m(Si)·M(SiO2)·M(Si) -1 , m(Fe2O3)=m(Fe)·M(Fe2O3)·(2M(Fe)) -1 , and m(SnO2)=m(Sn)·M(SnO2)·M(Sn) -1 The mass percentages of Al, SiO2, Fe2O3, and SnO2 are given by m(x)·100·(m(Al)+m(SiO2)+m(Fe2O3)+m(SnO2)). -1 It is further calculated as follows, where x = Al, SiO2, Fe2O3, or SnO2.

[0148] [Table 3]

[0149] Table 3 includes the measurements of the dry pigments according to the methods described in the chemical analysis. The measured numbers for the elements Fe, Si, and Sn are recalculated as results for SiO2, Fe2O3, and SnO2. Aluminum is calculated as metallic aluminum. Finally, the calculated numbers for Al and its oxides are normalized to 100%.

[0150] [Table 4]

[0151] Table 4 compares the pigments of the present invention (Examples 1-4) with state-of-the-art pigments (CQV Stellar Red, Merck Meoxal Victoria Red, Sun Chemical Paliocrom Brilliant Red, Sun Chemical Paliocrom Sparkling Red, Comparative Example 1, Comparative Example 2, Comparative Example 3) in terms of their basic properties: particle size distribution; color characteristics h15, C * 15, L * 15, h110, C * 110, L * 110; Opacity (ΣdE); Saturation range (C) * Width); Lightness width (L * This section describes the width and luminance factor (BF).

[0152] [Example 1] a) Suspend 140 g of aluminum Al1 (dried powder) as described in Table 2 in 1300-1600 mL of ethanol. Passivation of SiO2 occurs according to the method described in Example 1 of U.S. Patent No. 5607504, or European Patent Application Publication No. 0708154, or Japanese Patent No. 54081337. The resulting suspension of passivated aluminum, ethanol, ammonia, water, and non-hydrolyzed tetraethoxysilane / partially hydrolyzed tetraethoxysilane is filtered and washed with 1500 mL of ethanol in total. The received paste has a solid concentration of 50-60%, and the dried pigment has an Al to SiO2 mass ratio of approximately 4:1 as described in Table 3. b) Disperse SiO2-coated aluminum paste (75-100 g of dry powder) in 700 mL of demineralized water, and heat the stirred slurry to 73-78°C. The pH is set to 3.35 using 10% by mass of HNO3, adjusted to 3.1 using a solution of 0.2-0.3 g of Al2(SO4)3·16H2O in 30 mL of demineralized water, and maintained at 2.8 using 25% by mass of NaOH while adding an Fe(NO3)3 solution with a Fe mass concentration of 6-9% until the desired red color is achieved. Typical injection times range from 12 to 25 hours, and the final pigment has an Al:SiO2:Fe2O3 content of approximately 4:1:7, as shown in Table 3. For small samples, the slurry is filtered, washed twice with desalted water, or washed until a conductivity level of, for example, 200 μS is achieved. The ethanol or isopropanol and press cake are vacuum-dried at room temperature for 2–20 hours for small samples, or, if larger samples are made, are kept as an alcoholic paste with a solid concentration of 60–80% for use in the next step. c) Small samples of the dried pigment are annealed in a drying chamber at 240°C for 3 hours. Larger samples of the resulting pigment paste (45-60 g of dried powder) are dispersed in 730-750 g of isoparaffin fluid. The reaction mixture is heated under a nitrogen atmosphere to 195-220°C for 10 hours and stirred at 195-220°C for 6 hours. The slurry is filtered, washed with ethanol, and the press cake is vacuum-dried at room temperature for a further 5 minutes. The received paste has a solid concentration of approximately 60-80%.

[0153] [Example 2] a) Suspend 145 g of aluminum Al2 (dried powder) as described in Table 2 in 1300-1600 mL of ethanol. Passivation of SiO2 occurs according to the method described in Example 1 of U.S. Patent No. 5607504, or European Patent Application Publication No. 0708154, or Japanese Patent No. 54081337. The resulting suspension of passivated aluminum, ethanol, ammonia, water, and non-hydrolyzed tetraethoxysilane / partially hydrolyzed tetraethoxysilane is filtered and washed with 1500 mL of ethanol in total. The received paste has a solid concentration of 50-60%, and the dried pigment has an Al to SiO2 mass ratio of approximately 4:1. b) Disperse SiO2-coated aluminum paste (75-100 g of dry powder) in 700 mL of demineralized water, and heat the stirred slurry to 73-78°C. The pH is set to 3.35 using 35-10% by mass of HNO3, adjusted to 3.1 using a solution of 0.2-0.4 g of Al2(SO4)3·16H2O in 30 mL of demineralized water, and maintained at 2.8 with 25% by mass of NaOH while adding an Fe(NO3)3 solution with a Fe mass concentration of 6-9% until the desired red color is achieved. Typical injection times range from 12 to 25 hours, and the final pigment has an Al:SiO2:Fe2O3 content of approximately 4:1:7. For small samples, the slurry is filtered, washed twice with desalted water, or washed until a conductivity level of, for example, 200 μS is achieved. The ethanol or isopropanol and press cake are vacuum-dried at room temperature for 2–20 hours for small samples, or, if larger samples are made, are kept as an alcoholic paste with a solid concentration of 60–80% for use in the next step. c) Small samples of the dried pigment are annealed in a drying chamber at 240°C for 3 hours. A larger sample of the resulting pigment paste (60 g of dried powder) is dispersed in 730-750 g of isoparaffin fluid. The reaction mixture is heated under a nitrogen atmosphere to 195-220°C for 10 hours and stirred at 195-220°C for 6 hours. The slurry is filtered, washed with ethanol, and the press cake is vacuum-dried at room temperature for a further 5 minutes. The received paste has a solid concentration of approximately 60-80%.

[0154] [Example 3] a) Suspend 140 g of aluminum Al3 (dried powder) as described in Table 2 in 1300-1600 mL of ethanol. Passivation of SiO2 occurs according to the method described in Example 1 of U.S. Patent No. 5607504, or European Patent Application Publication No. 0708154, or Japanese Patent No. 54081337. The resulting suspension of passivated aluminum, ethanol, ammonia, water, and non-hydrolyzed tetraethoxysilane / partially hydrolyzed tetraethoxysilane is filtered and washed with 1500 mL of ethanol in total. The received paste has a solid concentration of 50-60%, and the dried pigment has an Al to SiO2 mass ratio of approximately 3:1. b) Disperse SiO2-coated aluminum paste (100 g dry powder) in 700 mL of demineralized water, and heat the stirred slurry to 73°C. The pH is set to 3.35 using 5-10% by mass of HNO3, adjusted to 3.1 using a solution of 0.45 g of Al2(SO4)3·16H2O in 30 mL of demineralized water, and maintained at 2.8 with 25% by mass of NaOH while adding an Fe(NO3)3 solution with a Fe mass concentration of 6-9% until the desired red color is achieved. Typical injection times range from 12 to 25 hours, and the final pigment has an Al:SiO2:Fe2O3 content of approximately 3:1:6.5. For small samples, the slurry is filtered, washed twice with demineralized water, and vacuum-dried with ethanol or isopropanol and press cake at room temperature for 2-20 hours for small samples. c) Small samples of the dried pigment are annealed in a drying chamber at 240°C for 3 hours.

[0155] [Example 4] a) Suspend 140 g of aluminum Al4 (dried powder) as described in Table 2 in 1300-1600 mL of ethanol. Passivation of SiO2 occurs according to the method described in Example 1 of U.S. Patent No. 5607504, or European Patent Application Publication No. 0708154, or Japanese Patent No. 54081337. The resulting suspension of passivated aluminum, ethanol, ammonia, water, and non-hydrolyzed tetraethoxysilane / partially hydrolyzed tetraethoxysilane is filtered and washed with 1500 mL of ethanol in total. The received paste has a solid concentration of 50-60%, and the dried pigment has an Al to SiO2 mass ratio of approximately 3:1. b) Disperse SiO2-coated aluminum paste (100 g dry powder) in 700 mL of demineralized water, and heat the stirred slurry to 73°C. The pH is set to 3.35 using 5-10% by mass of HNO3, adjusted to 3.1 using a solution of 0.4 g of Al2(SO4)3·16H2O in 30 mL of demineralized water, and maintained at 2.8 with 25% by mass of NaOH while adding an Fe(NO3)3 solution with a Fe mass concentration of 6-9% until the desired red color is achieved. Typical injection times range from 12 to 25 hours, and the final pigment has an Al:SiO2:Fe2O3 content of approximately 3:1:7. For small samples, the slurry is filtered, washed twice with demineralized water, and vacuum-dried with ethanol or isopropanol and press cake at room temperature for 2-20 hours. c) Small samples of the dried pigment are annealed in a drying chamber at 240°C for 3 hours.

[0156] [Comparative Example 1] a) Suspend 140 g of aluminum Al5 (dried powder) as described in Table 2 in 1300-1600 mL of ethanol. Passivation of SiO2 occurs according to the method described in Example 1 of U.S. Patent No. 5607504, or European Patent Application Publication No. 0708154, or Japanese Patent No. 54081337. The resulting suspension of passivated aluminum, ethanol, ammonia, water, and non-hydrolyzed tetraethoxysilane / partially hydrolyzed tetraethoxysilane is filtered and washed with 1500 mL of ethanol in total. The received paste has a solid concentration of 50-60%, and the dried pigment has an Al to SiO2 mass ratio of approximately 3:1. b) Disperse SiO2-coated aluminum paste (75 g dry powder) in 700 mL of demineralized water, and heat the stirred slurry to 73-78°C. The pH is set to 3.35 using 10% by mass of HNO3, adjusted to 3.1 using a solution of 0.3-0.45 g of Al2(SO4)3·16H2O in 30 mL of demineralized water, and maintained at 2.8 using 25% by mass of NaOH while adding an Fe(NO3)3 solution with a Fe mass concentration of 6-9% until the desired red color is achieved. Typical injection times range from 12 to 25 hours, and the final pigment has an Al:SiO2:Fe2O3 content of approximately 3:1:6. For small samples, the slurry is filtered, washed twice with desalted water, or washed until a conductivity level of, for example, 200 μS is achieved. The ethanol or isopropanol and press cake are vacuum-dried at room temperature for 2–20 hours for small samples, or, if larger samples are made, are kept as an alcoholic paste with a solid concentration of 60–80% for use in the next step. c) Small samples of the dried pigment are annealed in a drying chamber at 240°C for 3 hours. A larger sample of the resulting pigment paste (60 g of dried powder) is dispersed in 730-750 g of isoparaffin fluid. The reaction mixture is heated under a nitrogen atmosphere to 195-220°C for 10 hours and stirred at 195-220°C for 6 hours. The slurry is filtered, washed with ethanol, and the press cake is vacuum-dried at room temperature for a further 5 minutes. The received paste has a solid concentration of approximately 60-80%.

[0157] [Comparative Example 2] a) Suspend 140 g of aluminum Al6 (dried powder) as described in Table 2 in 1300-1600 mL of ethanol. Passivation of SiO2 occurs according to the method described in Example 1 of U.S. Patent No. 5607504, or European Patent Application Publication No. 0708154, or Japanese Patent No. 54081337. The resulting suspension of passivated aluminum, ethanol, ammonia, water, and non-hydrolyzed tetraethoxysilane / partially hydrolyzed tetraethoxysilane is filtered and washed with 1500 mL of ethanol in total. The received paste has a solid concentration of approximately 70%, and the dried pigment has an Al to SiO2 mass ratio of approximately 4.5:1. b) Disperse SiO2-coated aluminum paste (75 g dry powder) in 700 mL of demineralized water, and heat the stirred slurry to 73°C. The pH is set to 3.35 using 10% by mass of HNO3, adjusted to 3.1 using a solution of 0.3-0.45 g of Al2(SO4)3·16H2O in 30 mL of demineralized water, and maintained at 2.8 using 25% by mass of NaOH while adding an Fe(NO3)3 solution with a Fe mass concentration of 6-9% until the desired red color is achieved. Typical injection times range from 12 to 25 hours, and the final pigment has an Al:SiO2:Fe2O3 ratio of approximately 4.5:1:7. For small samples, the slurry is filtered, washed twice with demineralized water, and vacuum-dried with ethanol or isopropanol and press cake at room temperature for 2-20 hours. c) Small samples of the dried pigment are annealed in a drying chamber at 240°C for 3 hours.

[0158] [Comparative Example 3] a) Suspend 140 g of aluminum Al7 (dried powder) as described in Table 2 in 1300-1600 mL of ethanol. Passivation of SiO2 occurs according to the method described in Example 1 of U.S. Patent No. 5607504, or European Patent Application Publication No. 0708154, or Japanese Patent No. 54081337. The resulting suspension of passivated aluminum, ethanol, ammonia, water, and non-hydrolyzed tetraethoxysilane / partially hydrolyzed tetraethoxysilane is filtered and washed with 1500 mL of ethanol in total. The received paste has a solid concentration of approximately 80%, and the dried pigment has an Al to SiO2 mass ratio of approximately 7:1. b) Disperse SiO2-coated aluminum paste (100 g dry powder) in 700 mL of demineralized water, and heat the stirred slurry to 73°C. The pH is set to 3.35 using 10% by mass of HNO3, adjusted to 3.1 using a solution of 0.1-0.2 g of Al2(SO4)3·16H2O in 30 mL of demineralized water, and maintained at 2.8 using 25% by mass of NaOH while adding an Fe(NO3)3 solution with a Fe mass concentration of 6-9% until the desired red color is achieved. Typical injection times range from 12 to 25 hours, and the final pigment has an Al:SiO2:Fe2O3 ratio of approximately 7:1:9. For small samples, the slurry is filtered, washed twice with demineralized water, and vacuum-dried with ethanol or isopropanol and press cake at room temperature for 2-20 hours. c) Small samples of the dried pigment are annealed in a drying chamber at 240°C for 3 hours.

Claims

1. A plate-shaped metal core, The silicon-containing passivation layer on the upper surface of the plate-shaped metal core, The upper surface of the passivation layer, and a layer containing iron oxide and / or iron oxide hydroxide. A mid-tone red effect pigment, which includes, h15 is in the range of 25° ≤ h15 ≤ 49°, preferably 28° ≤ h15 ≤ 45°. BF is 140 to 165, preferably 145 to 165, most preferably 150 to 165. The concealing force is ΣdE < 110. Intermediate red effect pigment.

2. The aforementioned plate-shaped metal core has the following characteristics: a. Surface area (BET)≦4m ２ / g, preferably with a surface area (BET) ≤ 3.8 m² ２ / g, more preferably surface area (BET) ≤ 3.5m² ２ / g, b. Spread (span) of the particle size curve ≤ 1.2, preferably ≤ 1.

1. c. Concealing force ΣdE < 20, preferably concealing force ΣdE < 15, more preferably concealing force ΣdE < 13, d. Lightness L ＊ 15 > 153, preferably lightness L ＊ 15 > 155 The pigment according to claim 1, comprising aluminum flakes having the following properties.

3. The pigment according to claim 1 or 2, wherein the metal content is 25 to 60% by mass, preferably 25 to 40% by mass, and most preferably 25 to 38% by mass.

4. A pigment according to any one of claims 1 to 3, wherein the saturation range is 60 or more.

5. A pigment according to any one of claims 1 to 4, wherein the brightness range is 90 or more.

6. The pigment according to any one of claims 1 to 5, wherein the average particle size d50 is 16 μm or more.

7. The pigment according to any one of claims 1 to 6, wherein the layer of iron oxide and / or iron oxide hydroxide contains 10% by mass or less of other metal ions and / or metals individually.

8. The pigment according to any one of claims 1 to 7, wherein the layer of iron oxide and / or iron oxide hydroxide has a thickness or average thickness of 150 to 350 nm.

9. The pigment according to any one of claims 1 to 8, comprising one or more additional layers applied on a layer of iron oxide and / or iron oxide hydroxide.

10. The pigment according to claim 9, wherein the pigment comprises one or more additional layers selected from the group consisting of a silica layer, an organosilane layer, a polymer layer, or any combination thereof, on a layer of iron oxide and / or iron oxide hydroxide.

11. The aforementioned additional layer is SiO ２ The pigment according to claim 9 or 10, comprising 10% by mass or less.

12. The pigment according to any one of claims 1 to 11, wherein the aluminum flakes are produced by a ball milling method.

13. A method for producing an intermediate red effect pigment according to any one of claims 1 to 12, wherein the aluminum flakes are produced by a ball milling method.

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