Sparkling effect pigment

Abstract

An effect pigment based on a transparent plate-shaped substrate, the transparent plate-shaped substrate having a near refractive index layer coating close to the refractive index of the substrate, as a result effectively increasing the thickness of the substrate and producing a higher sparkle.

Description

Technical Field

[0001] The present invention relates to an effect pigment composition. The present invention further relates to a printing ink, a paint or a coating composition containing this effect pigment composition, a method for producing this effect pigment composition, and a method for increasing the sparkle of the effect pigment.

Background Art

[0002] The sparkle effect has been used as a design element in industrial design for decades. The sparkling effect has attracted attention in cosmetics, packaging, printing inks, and all kinds of coatings. Technically, the sparkling effect is produced by incorporating small light-reflecting flakes with a diameter of about 5 to 1000 μm into the surface coating or as a mass coloring of plastics or cosmetic powders.

[0003] In industrial coatings, there are limitations in particle size and thickness. The reason is that the coating after drying becomes considerably thinner than 50 μm. For example, in automotive coatings, the thickness of the latest base coat is less than 20 μm. As a result, what is required of the sparkling pigment is that it must be small enough to enable a smooth base coat with high gloss and at the same time enable strong sparkles.

[0004] Effect pigments based on glass flakes exhibit strong luster. In particular, glass flakes coated with oxides having a diameter of 50 to 250 μm and a thickness of 1 to 5 μm show desirable effects. However, due to their large particle size, automotive base coats are not possible with these flakes. Smaller (less than 20 μm) and thinner (less than 500 nm) glass flakes have also been tested as substrates, but so far, the reproducibility regarding the thickness and shape variations on a production scale is low.

[0005] The more successful base materials are Al2O3 flakes synthesized by an expensive crystallization process. Such flakes, after being coated with iron oxide or titanium oxide, become very uniform in size (D50 = 15 - 20 μm) and very smooth. They are excellent in light reflection and are widely used in automotive base coats. However, Al2O3 flake-based pigments are costly and abrasive, so a more cost-effective solution has been sought in the market. In particular, the abrasiveness of Al2O3 requires more expensive equipment in paint factories to withstand the severe polishing conditions of the paint based on it.

[0006] Mica-based effect pigments with similar particle sizes provide only a moderate sparkle effect compared to Al2O3 flake-based effect pigments. When using synthetic mica as the base for effect pigments, synthetic mica has a smoother surface quality compared to natural mica, so the sparkling performance can be enhanced. However, the sparkling performance of synthetic mica-based effect pigments is not as strong as that of Al2O3 flakes. Therefore, the inventors have conducted intensive research with the goal of selectively enhancing the sparkle of the flakes without sacrificing their applicability to thin base coats.

[0007] Surprisingly, it has been found that the sparkle effect of oxide-coated flakes can be adjusted by directly applying an inorganic coating with a near refractive index on the flakes and then coating with a high refractive index metal oxide. This discovery has not been disclosed in the state of the art so far.

[0008] US10214651B1 relates to an effect pigment for use with frit, where the effect pigment comprises a substrate coated with various layers, and the first layer is Al2O3, SiO2, zirconium silicate ZrSiO4, mullite 3Al2O3×2SiO2 or 2Al2O3×SiO2 (sintered mullite or fused mullite), or an alkaline earth metal silicate (MSiO3 (where M is Mg 2+ , Ca 2+ , Sr 2+or Ba 2+ ), or M2Si3O8, where M is Mg 2+ , Ca 2+ , Sr 2+ or Ba 2+ ), and is a low refractive index layer selected from the group consisting of. Details or purposes of the first low refractive index layer are not disclosed.

[0009] US7699927B1 provides a protective layer for an effect pigment containing a SiO2 layer. The thickness of SiO2 is 2 - 20 nm, or 0.5 - 10% by mass of the pigment. These effect pigments do not produce a sparkle effect.

[0010] CN108165053A provides a high-chroma anatase effect pigment achieved with a high-low-high refractive index stack. There is an additional silica layer on mica before the optical layer, but its purpose is not fully clear. Since the amount of silica in the initial layer is 0.01 - 2% by mass, a sparkle effect cannot be obtained.

[0011] US7485183B1 discloses a blend of a commercial pigment containing a glass flake-based effect pigment and various coatings, which may include a silica layer between the glass flake and other coating layers. The purpose of the silica layer is not disclosed.

[0012] US8883879B1 relates to the manufacture of pigment particles with an effect pigment adhered to a carrier material. Known effect pigments in the art are used, including an effect pigment containing glass flakes as a substrate. The glass flake-based effect pigment can also have a silica layer between the glass flake and the coating. The purpose of the silica layer is to protect the glass flake against elution during wet chemical coating.

[0013] US8500901B1 discloses an interference pigment based on a substrate of aluminum oxide and glass flakes. The purpose of the silica layer is to provide a silver-white interference pigment with high gloss (L value), chroma (coloring strength C*), and mechanical stability. The gloss mentioned there means lightness (L value) and is related to the CIELab system and multi-angle color measurement. The principle is to measure the angle-dependent reflectance in the visible region and mathematically derive color statistical data such as C*, L*, h, a, b.

[0014] US10597544B1 relates to an effect pigment based on a typical substrate (preferably glass flakes) having eight coating layers, where the first layer is silica. The purpose of the silica coating is to protect the glass surface from chemical modification, such as swelling, elution of glass components, or dissolution in an aggressive acidic coating solution.

[0015] EP2917285A1 relates to a multilayer-coated effect pigment having at least four oxide layers and an optional first SiO2 layer. The thickness of the SiO2 layer is 3 - 150 nm. The main purpose of this layer is to protect the glass flake substrate from chemical attack and optionally contains carbon black to enhance hiding power. The next layer is also a low refractive index layer with a thickness of 1 - 50 nm. The specific purpose of this layer is not described.

[0016] US8268069B1 relates to glass flakes coated with various layers and an optional first layer containing a SiO2 coating. The purpose of the silica coating is to protect the glass surface from chemical modification, such as swelling, elution of glass components, or dissolution in an aggressive acidic coating solution.

[0017] The listed patent documents mention providing some low refractive index layer on the substrate before the subsequent optical layer, but there is no description that the purpose of such a layer is to increase the effective thickness of the substrate and as a result obtain an effect pigment with increased sparkle.

[0018] Small-sized substrates, especially thin substrates, do not produce much sparkle when coated with various optical layers and converted into effect pigments. To increase the sparkle of effect pigments based on small-sized substrates, a near refractive index matching layer is applied to the substrate before applying the optical layer, essentially thickening the substrate and resulting in more sparkle.

[0019] The citation or identification of a document in this application does not admit that it is prior art to the present invention.

Prior Art Documents

Patent Documents

[0020]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

Patent Document 7

Patent Document 8

Patent Document 9

Summary of the Invention

Problems to be Solved by the Invention

[0021] The inventors conducted intensive research with the goal of selectively enhancing the sparkle of flakes without impairing the applicability to thin base coats.

Means for Solving the Problems

[0022] The present invention is attracted to an effect pigment based on a transparent plate-shaped substrate having a near refractive index coating that matches the refractive index of the substrate, as a result, effectively increases the thickness of the substrate, and then optionally combines optical layers. In one embodiment, the substrate belongs to the group of mica minerals, for example, muscovite is natural mica and fluorophlogopite is synthetic mica. Other types of transparent plate-shaped substrates include glass flakes, SiO2, Al2O3, BiOCl, kaolin, ZnO, BN, and perlite. In one embodiment, the near refractive index coating can have a refractive index within 0.3 of the substrate and include any material or combination of materials that provides the desired refractive index. Examples of materials for the near refractive index coating include, but are not limited to, SiO2, Al2O3, and MgO. Also, two or more metal oxides can be mixed to form a layer that matches the desired refractive index using the following formula, n = X A ·n A +X B ·n B (where n is the resulting refractive index of the blend, X A is the mole fraction of component A, n A is the refractive index of component A, X B is the mole fraction of component B, and n B is the refractive index of component B). Table 1 contains a list of related materials and numerical values regarding refractive indices. Table 2 shows examples of some blends that can be used to match the refractive index of mica.

[0023]

Table 1

[0024]

Table 2

[0025] The expression "near refractive index coating that matches the refractive index of the substrate" means that the near refractive index coating has a refractive index within 0.3 of the refractive index of one or more transparent plate-like substrates.

[0026] The expression "thickness" of the coating refers to the physical thickness of the coating.

[0027] The near refractive index coating can be applied to substrates of any size. However, substrates with a large particle size distribution (PSD) inherently have many sparkles, so it is more practical to apply it to small substrates such as those with a Dv50 (average particle size) of less than 30 microns. The near refractive index coating can be applied by any method, such as the aqueous precipitation method, sol-gel method, or CVD method. If desired, the applied near refractive index coating can be fired before applying an additional optical layer. The subsequent optical layer can include TiO2, Fe2O3, TiO2 / Fe2O3, TiO2 / SiO2 / TiO2, TiO2 / SiO2 / Fe2O3, Fe2O3 / SiO2 / TiO2, and Fe2O3 / SiO2 / Fe2O3. The increased sparkle of these effect pigments can be measured with a BYK-mac spectrophotometer and compared with effect pigments having an equivalent optical layer on an equivalent substrate without a coating that matches the initial near refractive index.

[0028] By using a coating that matches the near refractive index, the thickness of the substrate increases, the sparkle of the resulting effect pigment improves, and a small PSD is provided. Especially in automotive coatings, which is one of the end uses, a sparkle effect is often required, but pigments with a large particle size cannot be used.

Mode for Carrying Out the Invention

[0029] The present invention is further illustrated by the following series of numbered embodiments and combinations of embodiments resulting from the indicated dependencies and cross-references. In particular, in each instance where the scope of an embodiment is referred to, for example, in the context of terms such as "a composition according to any one of items 1 to 5", all embodiments within this scope are meant to be explicitly disclosed for a person skilled in the art, that is, it should be noted that this expression of the term is understood by a person skilled in the art to be synonymous with "a composition according to any one of items 1, 2, 3, 4, and 5". Further, it should be clearly noted that the following series of embodiments do not represent a set of claims that determine the scope of protection, but rather a preferably configured part of the description directed to general and preferred aspects of the present invention.

[0030] 1. An effect pigment composition comprising one or more transparent plate-like substrates, wherein the substrate is provided with a near refractive index coating that matches the refractive index of the substrate.

[0031] 2. The composition according to item 1, wherein the substrate is selected from the group consisting of mica, glass flakes, SiO2, Al2O3, BiOCl, kaolin, ZnO, BN, perlite, and mixtures thereof, preferably from the group consisting of mica, glass flakes, perlite, and mixtures thereof, more preferably, the substrate contains mica, and even more preferably is mica.

[0032] 3. The composition according to item 2, wherein the transparent plate-like substrate is mica selected from the group consisting of muscovite (natural mica) and fluorophlogopite (synthetic mica), preferably, the substrate contains fluorophlogopite, and even more preferably is fluorophlogopite.

[0033] 4. The composition according to any one of items 1 to 3, wherein the refractive index of the transparent plate-like substrate is in the range of 1.0 to 2.1, preferably in the range of 1.2 to 2.0, more preferably in the range of 1.3 to 1.9, and even more preferably in the range of 1.4 to 1.8.

[0034] 5. The refractive index of the near refractive index coating is in the range of 1.0 to 2.1, preferably in the range of 1.2 to 2.0, more preferably in the range of 1.3 to 1.9, still more preferably in the range of 1.4 to 1.8, and the composition according to any one of items 1 to 4.

[0035] 6. The near refractive index coating has a refractive index within 0.3 of the substrate, preferably in the range of 0.0 to 0.29, more preferably in the range of 0.0 to 0.20, still more preferably in the range of 0.0 to 0.15, and the composition according to any one of items 1 to 5.

[0036] 7. The near refractive index coating has a thickness in the range of 30 to 170 nm, preferably in the range of 40 to 160 nm, more preferably in the range of 50 to 150 nm, as determined according to high-resolution scanning electron microscopy, and the composition according to any one of items 1 to 6.

[0037] 8. 90 to 100% by mass, preferably 95 to 100% by mass, more preferably 98 to 100% by mass, still more preferably 99 to 100% by mass of the near refractive index coating consists of SiO2, Al2O3, MgO, ZnO, and mixtures thereof, and the composition according to any one of items 1 to 7.

[0038] 9. The near refractive index coating contains a material, and this material is selected from the group consisting of SiO2, Al2O3, MgO, ZnO, and mixtures thereof, preferably from the group consisting of SiO2, Al2O3, and mixtures thereof, more preferably, the material for the near refractive index coating contains SiO2, still more preferably SiO2, and the composition according to any one of items 1 to 8.

[0039] 10. The near refractive index coating consists of two metal oxides A and B, and these two metal oxides are mixed to form a near refractive index coating, and the refractive index of the near refractive index coating is determined using the following formula n = X A ·n A +X B ·n B (wherein n is the refractive index obtained for the near refractive index coating, X A is the mole fraction of metal oxide A, n A is the refractive index of metal oxide A, X B is the mole fraction of metal oxide B, n B is the refractive index of metal oxide B), the composition according to any one of items 1 to 9.

[0040] 11. The substrate has a Dv50 in the range of 5 to 100 microns determined according to Reference Example 1, preferably, the substrate has a Dv50 of less than 30 microns, more preferably, the substrate has a Dv50 in the range of 5 to 30 microns, more preferably in the range of 5 to 25 microns, the composition according to any one of items 1 to 10.

[0041] 12. The composition according to any one of items 1 to 11, further comprising a combination of subsequent optical layers.

[0042] 13. The subsequent optical layer is selected from the group consisting of TiO2, Fe2O3, TiO2 / Fe2O3, TiO2 / SiO2 / TiO2, TiO2 / SiO2 / Fe2O3, Fe2O3 / SiO2 / TiO2, and Fe2O3 / SiO2 / Fe2O3, preferably, the subsequent optical layer is selected from the group consisting of TiO2 and Fe2O3, more preferably, the subsequent optical layer comprises a TiO2 layer, more preferably a TiO2 layer, the composition according to item 12.

[0043] 14. Each of the subsequent optical layers has a thickness in the range of 20 to 300 nm, preferably in the range of 20 to 180 nm, more preferably in the range of 20 to 130 nm, determined according to high-resolution scanning electron microscopy, the composition according to item 12 or 13.

[0044] 15. Having a delta spark intensity ΔS_i in the range of 0.5 to 5.0, preferably in the range of 1.0 to 4.0, more preferably in the range of 2.0 to 3.0, determined according to Reference Example 2, the composition according to any one of items 1 to 14.

[0045] 16. The composition according to any one of items 1 to 15, wherein the near refractive index coating further contains SnO2.

[0046] 17. The composition according to any one of items 1 to 16, wherein the near refractive index coating is applied by a method selected from the group consisting of aqueous precipitation, sol-gel, and chemical vapor deposition.

[0047] 18. The composition according to any one of items 1 to 17, wherein the applied near refractive index coating is fired before applying an additional optical layer.

[0048] 19. A printing ink, paint, or coating composition comprising the composition according to any one of items 1 to 18.

[0049] 20. The printing ink, paint, or coating composition according to item 19, which is an automotive coating.

[0050] 21. A method for preparing the composition according to any one of items 1 to 18, wherein the near refractive index coating is applied onto a transparent plate-shaped substrate by a method selected from the group consisting of aqueous precipitation, sol-gel, and chemical vapor deposition.

[0051] 22. The method according to item 21, wherein the near refractive index coating is fired before applying a subsequent combination of optical layers.

[0052] 23. A method for enhancing the sparkle of an effect pigment based on a transparent plate-shaped substrate, the method comprising applying a near refractive index coating that matches the refractive index of the substrate.

[0053] 24. The method according to item 23, wherein the substrate is selected from the group consisting of mica, glass flakes, SiO2, Al2O3, BiOCl, kaolin, ZnO, BN, perlite, and mixtures thereof, preferably from the group consisting of mica, glass flakes, perlite, and mixtures thereof, more preferably the substrate contains mica, and even more preferably the substrate is mica.

[0054] 25. The transparent plate-shaped substrate is mica selected from the group consisting of muscovite (natural mica) and fluorophlogopite (synthetic mica), preferably, the substrate contains fluorophlogopite, and more preferably is fluorophlogopite, according to the method of item 24.

[0055] 26. The refractive index of the transparent plate-shaped substrate is in the range of 1.0 to 2.1, preferably in the range of 1.2 to 2.0, more preferably in the range of 1.3 to 1.9, and still more preferably in the range of 1.4 to 1.8, according to the method of item 23.

[0056] 27. The refractive index of the near refractive index coating is in the range of 1.0 to 2.1, preferably in the range of 1.2 to 2.0, more preferably in the range of 1.3 to 1.9, and still more preferably in the range of 1.4 to 1.8, according to the method of item 23.

[0057] 28. The near refractive index coating has a refractive index within 0.3 of the substrate, preferably in the range of 0.0 to 0.29, more preferably in the range of 0.0 to 0.20, and still more preferably in the range of 0.0 to 0.15, according to the method of item 23.

[0058] 29. The near refractive index coating has a thickness in the range of 30 to 170 nm, preferably in the range of 40 to 160 nm, more preferably in the range of 50 to 150 nm, determined according to the high-resolution scanning electron microscopy method, according to the method of item 23.

[0059] 30. 90 to 100% by mass, preferably 95 to 100% by mass, more preferably 98 to 100% by mass, and still more preferably 99 to 100% by mass of the near refractive index coating consists of SiO2, Al2O3, MgO, ZnO, and mixtures thereof, according to the method of item 23.

[0060] 31. The method according to item 23, wherein the near refractive index coating contains a material, and the material is selected from the group consisting of SiO2, Al2O3, MgO, and mixtures thereof, preferably from the group consisting of SiO2, Al2O3, and mixtures thereof, and more preferably, the material for the near refractive index coating contains SiO2, and more preferably is SiO2.

[0061] 32. The near refractive index coating consists of two metal oxides A and B, and the two metal oxides are mixed to form a near refractive index coating, and the refractive index of the near refractive index coating is determined using the following formula n = X A ·n A +X B ·n B (wherein n is the obtained refractive index of the near refractive index coating, X A is the molar fraction of metal oxide A, n A is the refractive index of metal oxide A, X B is the molar fraction of metal oxide B, and n B is the refractive index of metal oxide B), the method according to item 23.

[0062] 33. The method according to item 23, wherein the substrate has a Dv50 in the range of 5 to 100 microns determined according to Reference Example 1, preferably the substrate has a Dv50 of less than 30 microns, and more preferably, the substrate has a Dv50 in the range of 5 to 30 microns, and more preferably in the range of 5 to 25 microns.

[0063] 34. The method according to item 23, further comprising a combination of subsequent optical layers.

[0064] 35. The subsequent optical layer is selected from the group consisting of TiO2, Fe2O3, TiO2 / Fe2O3, TiO2 / SiO2 / TiO2, TiO2 / SiO2 / Fe2O3, Fe2O3 / SiO2 / TiO2, and Fe2O3 / SiO2 / Fe2O3, preferably, the subsequent optical layer is selected from the group consisting of TiO2 and Fe2O3, more preferably, the subsequent optical layer includes a TiO2 layer, and even more preferably is a TiO2 layer, the method according to item 23.

[0065] 36. Each of the subsequent optical layers has a thickness in the range of 20 to 300 nm, preferably in the range of 20 to 180 nm, more preferably in the range of 20 to 130 nm, determined according to high-resolution scanning electron microscopy, the method according to item 23.

[0066] 37. Having a delta spark intensity ΔS_i in the range of 0.5 to 5.0, preferably in the range of 1.0 to 4.0, more preferably in the range of 2.0 to 3.0, determined according to Reference Example 2, the method according to item 23.

[0067] 38. The near refractive index coating further contains SnO2, the method according to item 23.

[0068] 39. The near refractive index coating is applied by a method selected from the group consisting of aqueous precipitation, sol-gel, and chemical vapor deposition, the method according to item 23.

[0069] 40. Before applying the additional optical layer, the applied near refractive index coating is fired, the method according to item 23.

[0070] Furthermore, the present invention relates to (i) A transparent plate-shaped substrate having a refractive index in the range of 1.0 to 2.1; (ii) A first coating on the transparent plate-shaped substrate according to (i), including at least one first metal oxide selected from the group consisting of SiO2, Al2O3, MgO, ZnO, and mixtures thereof Regarding the effect pigment containing, here, the refractive index of the first coating according to (ii) is at most 0.3 of the refractive index of the transparent flat substrate according to (i).

[0071] Preferably, the refractive index of the transparent plate-shaped substrate according to (i) is in the range of 1.2 to 2.0, preferably in the range of 1.3 to 1.9, more preferably in the range of 1.4 to 1.8.

[0072] Preferably, the transparent plate-shaped substrate according to (i) is selected from the group consisting of mica, glass flakes, SiO2, Al2O3, BiOCl, kaolin, ZnO, BN, perlite, and mixtures thereof, preferably selected from the group consisting of mica, glass flakes, perlite, and mixtures thereof, more preferably, the transparent plate-shaped substrate according to (i) contains mica, and more preferably is mica.

[0073] When the transparent plate-shaped substrate according to (i) is mica, this mica is muscovite, fluorophlogopite or a mixture thereof, preferably fluorophlogopite.

[0074] Muscovite is natural mica, and fluorophlogopite is synthetic mica.

[0075] Preferably, the transparent plate-shaped substrate according to (i) has a Dv50 in the range of 5 to 100 microns, more preferably in the range of 5 to 50 microns, more preferably in the range of 5 to 30 microns, more preferably in the range of 5 to 25 microns, as determined according to Reference Example 1.

[0076] Preferably, the refractive index of the first coating according to (ii) is in the range of 1 to 2.1, more preferably in the range of 1.2 to 2.0, more preferably in the range of 1.3 to 1.9, more preferably in the range of 1.4 to 1.8.

[0077] Preferably, the refractive index of the first coating according to (ii) is in the range of 0 to 0.29 of the refractive index of the transparent plate-shaped substrate according to (i), more preferably in the range of 0.0 to 0.20, more preferably in the range of 0.0 to 0.15.

[0078] Preferably, 90 to 100% by mass, preferably 95 to 100% by mass, more preferably 98 to 100% by mass, and even more preferably 99 to 100% by mass of the first coating according to (ii) consists of at least one first metal oxide selected from SiO2, Al2O3, MgO, ZnO, and mixtures thereof.

[0079] Preferably, the at least one first metal oxide is selected from the group consisting of SiO2, Al2O3, MgO, and mixtures thereof, more preferably from the group consisting of SiO2, Al2O3, and mixtures thereof, even more preferably the first metal oxide contains SiO2, and even more preferably is SiO2.

[0080] Preferably, the first coating according to (ii) has a thickness in the range of 30 to 170 nm, more preferably in the range of 40 to 160 nm, and even more preferably in the range of 50 to 150 nm, as determined by high-resolution scanning electron microscopy.

[0081] The expression "thickness" of the coating refers to the physical thickness of the coating.

[0082] Preferably, the first coating according to (ii) consists of k metal oxides A(i) (where i = 1...k, k>1), where the refractive index n of the first coating is defined by the following formula

[0083]

Equation

[0084] (where X A (i) is the mole fraction of the metal oxide A(i) contained in the first coating; n A (i) is the refractive index of the metal oxide A(i) as an individual compound).

[0085] Preferably, the first coating according to (ii) further contains SnO₂.

[0086] Preferably, any one of the effect pigments of a specific preferred embodiment of the present invention (iii) further includes a second coating on the first coating according to (ii), wherein the second coating has a refractive index in the range of 2.2 to 4 and contains at least one second metal oxide selected from the group consisting of TiO₂, Fe₂O₃, Fe₃O₄, and mixtures thereof, preferably at least one second metal oxide selected from the group consisting of TiO₂, Fe₂O₃, and mixtures thereof, and more preferably the second metal oxide contains TiO₂.

[0087] When any one of the effect pigments of a specific preferred embodiment of the present invention includes the second coating according to (iii), the refractive index of the second coating according to (iii) is in the range of 2.5 to 3.5.

[0088] Preferably, 90 to 100% by mass, preferably 95 to 100% by mass, more preferably 98 to 100% by mass, and still more preferably 99 to 100% by mass of the second coating according to (iii) consists of at least one second metal oxide selected from the group consisting of TiO₂, Fe₂O₃, Fe₃O₄, and mixtures thereof.

[0089] Preferably, the second coating according to (iii) has a thickness in the range of 20 to 300 nm, preferably 20 to 180 nm, more preferably 20 to 130 nm, as determined by high-resolution scanning electron microscopy.

[0090] Preferably, the second coating according to (iii) further contains SnO₂.

[0091] Preferably, any one of the effect pigments of a specific preferred embodiment of the present invention includes two coatings, where the first coating according to (ii) contains SiO₂ and the second coating according to (iii) contains TiO₂, or (ii) The first coating contains SiO2, and (iii) the second coating contains Fe2O3.

[0092] Preferably, any one of the effect pigments of certain preferred embodiments of the present invention (iv) further includes a third coating on the second coating by (iii), The third coating has a refractive index in the range of 1 to 4 and contains at least one third metal oxide selected from the group consisting of SiO2, TiO2, Fe2O3, Fe3O4, and mixtures thereof, preferably selected from the group consisting of SiO2, TiO2, Fe2O3, and mixtures thereof.

[0093] When any one of the effect pigments of certain preferred embodiments of the present invention includes a third coating by (iv), the refractive index of the third coating by (iv) is in the range of 2.5 to 3.5.

[0094] Preferably, 90 to 100% by mass, preferably 95 to 100% by mass, more preferably 98 to 100% by mass, and still more preferably 99 to 100% by mass of the third coating by (iv) consists of at least one second metal oxide selected from the group consisting of SiO2, TiO2, Fe2O3, Fe3O4, and mixtures thereof.

[0095] Preferably, the third coating by (iv) has a thickness in the range of 20 to 300 nm, preferably 20 to 180 nm, more preferably 20 to 130 nm, as determined by high-resolution scanning electron microscopy.

[0096] Preferably, the third coating by (iv) further contains SnO2.

[0097] Preferably, any one of the effect pigments of certain preferred embodiments of the present invention includes three coatings, where the first coating by (ii) contains SiO2, the second coating by (iii) contains TiO2, and the third coating by (iv) contains Fe2O3.

[0098] Preferably, any one of the effect pigments of a specific preferred embodiment of the present invention further comprises a fourth coating on the third coating according to (v)(iv), wherein the fourth coating has a refractive index in the range of 2.2 to 4 and comprises at least one fourth metal oxide selected from the group consisting of TiO2, Fe2O3, Fe3O4, and mixtures thereof, preferably at least one selected from the group consisting of TiO2, Fe2O3, and mixtures thereof; more preferably, the second metal oxide comprises TiO2, and even more preferably is TiO2.

[0099] When any one of the effect pigments of a specific preferred embodiment of the present invention comprises a fourth coating according to (v), the refractive index of the fourth coating according to (v) is in the range of 2.5 to 3.5.

[0100] Preferably, 90 to 100% by mass, preferably 95 to 100% by mass, more preferably 98 to 100% by mass, even more preferably 99 to 100% by mass of the fourth coating according to (v) consists of at least one second metal oxide selected from the group consisting of TiO2, Fe2O3, Fe3O4, and mixtures thereof.

[0101] Preferably, the fourth coating according to (v) has a thickness in the range of 20 to 300 nm, preferably in the range of 20 to 180 nm, more preferably in the range of 20 to 130 nm, as determined by high-resolution scanning electron microscopy.

[0102] Preferably, the fourth coating according to (v) further comprises SnO2.

[0103] Preferably, any one of the effect pigments of a specific preferred embodiment of the present invention comprises four coatings, wherein the first coating according to (ii) comprises SiO2, the second coating according to (iii) comprises TiO2, the third coating according to (iv) comprises SiO2, and the fourth coating according to (v) comprises TiO2; or (ii) the first coating by (ii) contains SiO2, the second coating by (iii) contains TiO2, the third coating by (iv) contains SiO2, and the fourth coating by (v) contains Fe2O3; or (ii) the first coating by (ii) contains SiO2, the second coating by (iii) contains Fe2O3, the third coating by (iv) contains SiO2, and the fourth coating by (v) contains TiO2; or (ii) the first coating by (ii) contains SiO2, the second coating by (iii) contains Fe2O3, the third coating by (iv) contains SiO2, and the fourth coating by (v) contains Fe2O3.

[0104] Preferably, any one of the effect pigments of a specific preferred embodiment of the present invention has a delta sparkle intensity ΔS_i in the range of 0.5 to 5.0, preferably in the range of 1.0 to 4.0, more preferably in the range of 2.0 to 3.0, as determined according to Reference Example 2.

[0105] The present invention also relates to a method for preparing an effect pigment, preferably any one of the effect pigments of a specific preferred embodiment of the present invention, the method comprising the following steps: (a) providing a transparent plate-like substrate having a refractive index in the range of 1.0 to 2.1; (b) coating a first composition containing at least one first metal oxide precursor selected from the group consisting of Si, Al, Mg, Zn, and mixtures thereof on the transparent plate-like substrate to obtain a first unfired coating; (c) firing the transparent plate-like substrate and the first unfired coating in air at normal pressure at a temperature in the range of 650 to 950 °C for 5 to 60 minutes; (d) obtaining an effect pigment comprising a first coating containing at least one first metal oxide selected from the group consisting of SiO2, Al2O3, MgO, ZnO, and mixtures thereof on the transparent plate-like substrate, wherein the first coating has a refractive index of at most 0.30 of the transparent plate-like substrate; comprising, The coating in step (b) is performed by one or more selected from aqueous precipitation, sol-gel coating, and chemical vapor deposition.

[0106] Preferably, before step (c), (b.i) coating a second composition comprising at least one second metal oxide precursor selected from the group consisting of Ti, Fe, and mixtures thereof on the first coating to obtain a second unfired coating further comprising.

[0107] Preferably, before step (b.i), the transparent plate-like substrate and the first unfired coating obtained according to step (b) are subjected to firing at a temperature in the range of 650 to 950 °C for 5 to 60 minutes at normal pressure in the atmosphere.

[0108] Preferably, any one method of a specific preferred embodiment of the present invention (b.ii) further comprising a step of coating at least one further composition on the second coating obtained according to step (b.1), wherein when at least two further compositions are coated, they are preferably coated in sequence, whereby at least a third coating is obtained on the second coating, a fourth coating is obtained on the third coating, and more preferably, before coating a further composition on a given coating, the coating is subjected to firing.

[0109] The present invention also relates to an effect pigment obtainable or obtained by any one method of a specific preferred embodiment of the present invention.

[0110] The present invention also relates to a method of using any one effect pigment of a specific preferred embodiment of the present invention for preparing one or more of printing inks, paints, and coating compositions and / or as a component thereof.

[0111] Preferably, the coating composition is an automotive coating composition.

[0112] The present invention also relates to a method for preparing one or more of printing inks, paints, and coating compositions, which comprises using an effect pigment of any one of the specific preferred embodiments of the present invention as a component.

[0113] Preferably, the coating composition is an automotive coating composition.

[0114] The present invention also relates to printing inks, paints, and / or coating compositions comprising, or consisting of, an effect pigment of any one of the specific preferred embodiments of the present invention.

[0115] The present invention also relates to a method of using an effect pigment of any one of the specific preferred embodiments of the present invention as a component in printing inks, paints, and coating compositions to increase the sparkle effect.

[0116] The present invention also relates to a method for enhancing the sparkle effect of one or more of printing inks, paints, and coating compositions, which comprises using an effect pigment of any one of the specific preferred embodiments of the present invention as a component.

[0117] The present invention is further illustrated by the following set of embodiments and combinations of embodiments resulting from the dependencies and cross-references shown. In particular, in each instance where the scope of an embodiment is referred to, for example, in the context of terms such as "the effect pigment according to any one of Embodiments 1 to 4", it is to be noted that all embodiments within this scope are explicitly disclosed for those skilled in the art, that is, the expression of this term is understood by those skilled in the art to be synonymous with "the effect pigment according to any one of Embodiments 1, 2, 3, and 4". Further, the following set of embodiments represents a suitably configured part of a general description directed to preferred aspects of the present invention, and thus preferably supports the claims of the present invention, but is not indicative of representing the claims of the present invention.

[0118] 1. (i) A transparent plate-shaped substrate having a refractive index in the range of 1.0 to 2.1; (ii) A first coating on the transparent plate-shaped substrate according to (i), containing at least one first metal oxide selected from the group consisting of SiO2, Al2O3, MgO, ZnO, and mixtures thereof An effect pigment comprising the above, wherein the refractive index of the first coating according to (ii) is at most 0.3 of the refractive index of the transparent plate-shaped substrate according to (i).

[0119] 2. The effect pigment according to Embodiment 1, wherein the refractive index of the transparent plate-shaped substrate according to (i) is in the range of 1.2 to 2.0, preferably in the range of 1.3 to 1.9, more preferably in the range of 1.4 to 1.8.

[0120] 3. The transparent plate-shaped substrate according to (i) is selected from the group consisting of mica, glass flakes, SiO2, Al2O3, BiOCl, kaolin, ZnO, BN, perlite, and mixtures thereof, more preferably from the group consisting of mica, glass flakes, perlite, and mixtures thereof, and even more preferably, the transparent plate-shaped substrate according to (i) contains mica, and even more preferably is mica. The effect pigment according to Embodiment 1 or 2.

[0121] 4. The mica is muscovite, fluorophlogopite or a mixture thereof, preferably fluorophlogopite. The effect pigment according to Embodiment 3.

[0122] 5. The transparent plate-shaped substrate according to (i) has a Dv50 in the range of 5 to 100 μm, preferably in the range of 5 to 50 μm, more preferably in the range of 5 to 30 μm, even more preferably in the range of 5 to 25 μm, determined according to Reference Example 1. The effect pigment according to any one of Embodiments 1 to 4.

[0123] 6. The refractive index of the first coating according to (ii) is in the range of 1 to 2.1, preferably in the range of 1.2 to 2.0, more preferably in the range of 1.3 to 1.9, and even more preferably in the range of 1.4 to 1.8. The effect pigment according to any one of Embodiments 1 to 5.

[0124] 7. The refractive index of the first coating according to (ii) is in the range of 0 to 0.29, preferably in the range of 0.0 to 0.20, and more preferably in the range of 0.0 to 0.15 of the refractive index of the transparent plate-like substrate according to (i). The effect pigment according to any one of Embodiments 1 to 6.

[0125] 8. 90 to 100% by mass, preferably 95 to 100% by mass, more preferably 98 to 100% by mass, and even more preferably 99 to 100% by mass of the first coating according to (ii) consists of at least one first metal oxide selected from SiO2, Al2O3, MgO, ZnO, and mixtures thereof. The effect pigment according to any one of Embodiments 1 to 7.

[0126] 9. The at least one first metal oxide is selected from the group consisting of SiO2, Al2O3, MgO, and mixtures thereof, preferably from the group consisting of SiO2, Al2O3, and mixtures thereof. More preferably, the first metal oxide contains SiO2, and even more preferably, it is SiO2. The effect pigment according to any one of Embodiments 1 to 8.

[0127] 10. The first coating according to (ii) has a thickness in the range of 30 to 170 nm, more preferably in the range of 40 to 160 nm, and even more preferably in the range of 50 to 150 nm, as determined by high-resolution scanning electron microscopy. The effect pigment according to any one of Embodiments 1 to 9.

[0128] 11. The first coating according to (ii) consists of k metal oxides A(i) (where i = 1...k, k > 1), and the refractive index n of the first coating is defined by the following formula

[0129]

Number

[0130] (wherein X A (i) is the molar fraction of the metal oxide A(i) contained in the first coating; n A (i) is the refractive index of the metal oxide A(i) as an individual compound), the effect pigment according to any one of Embodiments 1 to 10.

[0131] 12. The effect pigment according to any one of Embodiments 1 to 11, wherein the first coating according to (ii) further contains SnO2.

[0132] 13. Further includes a second coating on the first coating according to (iii)(ii), the second coating has a refractive index in the range of 2.2 to 4, and includes at least one second metal oxide selected from the group consisting of TiO2, Fe2O3, Fe3O4, and mixtures thereof, preferably from the group consisting of TiO2, Fe2O3, and mixtures thereof, and more preferably the second metal oxide contains TiO2, the effect pigment according to any one of Embodiments 1 to 12.

[0133] 14. The effect pigment according to Embodiment 13, wherein the refractive index of the second coating according to (iii) is in the range of 2.5 to 3.5.

[0134] 15. 90 to 100% by mass, preferably 95 to 100% by mass, more preferably 98 to 100% by mass, more preferably 99 to 100% by mass of the second coating according to (iii) consists of at least one second metal oxide selected from the group consisting of TiO2, Fe2O3, Fe3O4, and mixtures thereof, the effect pigment according to Embodiment 13 or 14.

[0135] 16. The second coating according to (iii) has a thickness in the range of 20 to 300 nm, preferably in the range of 20 to 180 nm, more preferably in the range of 20 to 130 nm, as determined by high-resolution scanning electron microscopy method, the effect pigment according to any one of Embodiments 13 to 15.

[0136] 17. The second coating according to (iii) further contains SnO2, the effect pigment according to any one of Embodiments 13 to 16.

[0137] 18. The effect pigment contains two coatings, the first coating according to (ii) contains SiO2, and the second coating according to (iii) contains TiO2, or the first coating according to (ii) contains SiO2, and the second coating according to (iii) contains Fe2O3, the effect pigment according to any one of Embodiments 13 to 17.

[0138] 19. Further includes a third coating on the second coating according to (iv)(iii), the third coating has a refractive index in the range of 1 to 4 and contains at least one third metal oxide selected from the group consisting of SiO2, TiO2, Fe2O3, Fe3O4, and mixtures thereof, preferably from the group consisting of SiO2, TiO2, Fe2O3, and mixtures thereof, the effect pigment according to any one of Embodiments 13 to 18.

[0139] 20. The refractive index of the third coating according to (iv) is in the range of 2.5 to 3.5, the effect pigment according to Embodiment 18.

[0140] 21. 90 to 100% by mass, preferably 95 to 100% by mass, more preferably 98 to 100% by mass, more preferably 99 to 100% by mass of the third coating according to (iv) consists of at least one second metal oxide selected from the group consisting of SiO2, TiO2, Fe2O3, Fe3O4, and mixtures thereof, the effect pigment according to Embodiment 18 or 19.

[0141] 22. The third coating according to (iv) has a thickness in the range of 20 to 300 nm, preferably in the range of 20 to 180 nm, more preferably in the range of 20 to 130 nm, as determined by high-resolution scanning electron microscopy, and is the effect pigment according to any one of Embodiments 18 to 20.

[0142] 23. The third coating according to (iv) further contains SnO2, and is the effect pigment according to any one of Embodiments 18 to 22.

[0143] 24. The effect pigment contains three coatings, the first coating according to (ii) contains SiO2, the second coating according to (iii) contains TiO2, and the third coating according to (iv) contains Fe2O3, and is the effect pigment according to any one of Embodiments 18 to 23.

[0144] 25. Further includes a fourth coating on the third coating according to (v)(iv), The fourth coating has a refractive index in the range of 2.2 to 4 and contains at least one fourth metal oxide selected from the group consisting of TiO2, Fe2O3, Fe3O4, and mixtures thereof, preferably from the group consisting of TiO2, Fe2O3, and mixtures thereof, and more preferably, the second metal oxide contains TiO2, and more preferably is TiO2, and is the effect pigment according to any one of Embodiments 18 to 24.

[0145] 26. The refractive index of the fourth coating according to (v) is in the range of 2.5 to 3.5, and is the effect pigment according to Embodiment 24.

[0146] 27. 90 to 100% by mass, preferably 95 to 100% by mass, more preferably 98 to 100% by mass, more preferably 99 to 100% by mass of the fourth coating according to (v) consists of at least one second metal oxide selected from the group consisting of TiO2, Fe2O3, Fe3O4, and mixtures thereof, and is the effect pigment according to Embodiment 25 or 26.

[0147] 28. The fourth coating according to (v) has a thickness in the range of 20 to 300 nm, preferably in the range of 20 to 180 nm, more preferably in the range of 20 to 130 nm, as determined by high-resolution scanning electron microscopy method, and is the effect pigment according to any one of Embodiments 25 to 27.

[0148] 29. The fourth coating according to (v) further contains SnO2, and is the effect pigment according to any one of Embodiments 25 to 28.

[0149] 30. The effect pigment contains four coatings, the first coating according to (ii) contains SiO2, the second coating according to (iii) contains TiO2, the third coating according to (iv) contains SiO2, and the fourth coating according to (v) contains TiO2; or the first coating according to (ii) contains SiO2, the second coating according to (iii) contains TiO2, the third coating according to (iv) contains SiO2, and the fourth coating according to (v) contains Fe2O3; or the first coating according to (ii) contains SiO2, the second coating according to (iii) contains Fe2O3, the third coating according to (iv) contains SiO2, and the fourth coating according to (v) contains TiO2; or the first coating according to (ii) contains SiO2, the second coating according to (iii) contains Fe2O3, the third coating according to (iv) contains SiO2, and the fourth coating according to (v) contains Fe2O3, and is the effect pigment according to any one of Embodiments 25 to 29.

[0150] 31. Having a delta sparkle intensity ΔS_i in the range of 0.5 to 5.0, preferably in the range of 1.0 to 4.0, more preferably in the range of 2.0 to 3.0, as determined according to Reference Example 2, and is the effect pigment according to any one of Embodiments 1 to 30.

[0151] 32. A method for preparing an effect pigment, preferably the effect pigment according to any one of Embodiments 1 to 31, comprising the following steps: (a) providing a transparent plate-shaped substrate having a refractive index in the range of 1.0 to 2.1; (b) coating a first composition containing at least one first metal oxide precursor selected from the group consisting of Si, Al, Mg, Zn, and mixtures thereof onto the transparent plate-shaped substrate to obtain a first unfired coating; (c) firing the transparent plate-shaped substrate and the first unfired coating in air at normal pressure at a temperature in the range of 650 to 950 °C for 5 to 60 minutes; (d) obtaining an effect pigment containing a first coating containing at least one first metal oxide selected from the group consisting of SiO2, Al2O3, MgO, ZnO, and mixtures thereof on the transparent plate-shaped substrate, wherein the first coating has a refractive index of at most 0.30 of the transparent plate-shaped substrate; comprising, a method, wherein the coating according to step (b) is performed by one or more selected from aqueous precipitation, sol-gel coating, and chemical vapor deposition.

[0152] 33. Before step (c), (b.i) coating a second composition containing at least one second metal oxide precursor selected from the group consisting of Ti, Fe, and mixtures thereof onto the first coating to obtain a second unfired coating The method according to Embodiment 32, further comprising.

[0153] 34. Before step (b.i), subjecting the transparent plate-shaped substrate and the first unfired coating obtained according to step (b) to firing in air at normal pressure at a temperature in the range of 650 to 950 °C for 5 to 60 minutes. The method according to Embodiment 32 or 33.

[0154] 35. (b.ii) further comprising a step of coating at least one further composition onto the second coating obtained according to step (b.1), When at least two additional compositions are coated, they are preferably coated in sequence, whereby at least a third coating is obtained on the second coating, a fourth coating is obtained on the third coating, and more preferably, the coating is subjected to firing before coating an additional composition on a given coating. The method according to any one of Embodiments 32 to 34.

[0155] 37. An effect pigment obtainable or obtained by the method according to any one of Embodiments 32 to 36.

[0156] 38. Use of the effect pigment according to any one of Embodiments 1 to 31 and 37 for preparing one or more of printing inks, paints and coating compositions and / or as a component thereof.

[0157] 39. The use method according to Embodiment 38, wherein the coating composition is an automotive coating composition.

[0158] 40. A method for preparing one or more of printing inks, paints and coating compositions, comprising using the effect pigment according to any one of Embodiments 1 to 31 and 37 as a component.

[0159] 41. The method according to Embodiment 40, wherein the coating composition is an automotive coating composition.

[0160] 42. A printing ink, paint and / or coating composition comprising or consisting of the effect pigment according to any one of Embodiments 1 to 31 and 37.

[0161] 43. Use of the effect pigment according to any one of Embodiments 1 to 31 and 37 as a component in printing inks, paints and coating compositions for increasing the sparkle effect.

[0162] A method for enhancing one or more sparkle effects of printing inks, paints, and coating compositions, comprising using the effect pigment according to any one of Embodiments 1 to 31 and 37 as a component.

[0163] The present invention has been described in detail, including its preferred embodiments. However, it will be understood by those skilled in the art that, in view of the present disclosure, changes and / or improvements belonging to the scope and spirit of the present invention can be added to the present invention.

[0164] The present invention is further illustrated by the following non-limiting examples, which are not intended to limit the scope of the present invention and should not be construed as limiting.

Examples

[0165] Reference Example Reference Example 1 (Determination of Dv50) The Dv50 value was determined using a Malvern Mastersizer device.

[0166] Reference Example 2 (Determination of Sparkle Value and CIELab Value) The sparkle grade S_G represents the overall sparkle of the pigment, which is a mathematical combination of the values of S_i and S_a. S_i represents the sparkle intensity and is related to the intensity of the detected light beam. S_a represents the sparkle area and is related to the number of reflections of light per unit surface area.

[0167] The sparkle grades S_G, S_i, and S_a, and the h, C*, L*, ΔH*, ΔC*, ΔL*, and ΔE* values of the pigments according to the present invention were determined at angles of 15° and -15° using a BYK-mac device (manufactured by BYK Gardner). To determine the sparkle and CIELab data of the pigments, a dried and cured coating film obtained by 90:10 black reduction was applied and measured as follows: The pigment was incorporated (as a 50:50 slurry of the pigment in a solvent that is part of the varnish) at a total pigment concentration of 5% by mass (based on the total mass of the wet varnish) by stirring in a conventional solvent-based medium-solids cellulose acetate butyrate (CAB) / polyester varnish (pigment / binder is 20 / 100) until the pigment was finally dispersed. The completed varnish was applied to an aluminum panel by air pressure spraying to a wet film thickness of about 150 - 160 μm and then dried at room temperature. After drying, the base coat was overcoated with a 1K clear coat (a clear coat containing blocked isocyanate, an acrylic polymer having OH functionality, a melamine crosslinking agent, and other additives such as a UV absorber, an antioxidant, and a leveling agent) and dried and cured at 135°C. After curing, the thickness of the base coat was about 20 μm and the thickness of the clear coat was about 40 μm.

[0168] Reference Example 3 (Determination of Thickness) The thickness was determined using a cross-section of the pigment in the resin. The cross-section was obtained by wet diamond cutting and mechanical polishing. The thickness of the obtained cross-section was determined using a high-resolution scanning electron microscope and EDS observation. The equipment used was SEM (JSM7800F, JOEL) and EDS (X-MAX80mm2, Oxford).

[0169] Examples and Comparative Examples Example 1 A 10% aqueous slurry containing 200 g of synthetic mica flakes (fluorophlogopite, average particle size (Dv50) ~ 20 microns) was stirred at room temperature. The pH of the slurry was adjusted to 1.4 with 28% HCl, and then 22.4 g of 20% SnCl4·5H2O (an aqueous solution containing 20 mass% SnCl4·5H2O and 80 mass% water) was added at a rate of 1.0 g / min while maintaining the pH at 1.40 by the addition of 10% NaOH. The slurry was stirred for 30 minutes before heating to 74 °C. At this temperature, the pH of the slurry was slowly raised to 7.8 with 35% NaOH. Next, 900 g of 20% Na2SiO3·5H2O (an aqueous solution containing 20 mass% Na2SiO3·5H2O and 80 mass% water) was added at 2.0 g / min while maintaining the pH at 7.80 by the addition of 28% hydrochloric acid. After the addition was complete, the pH of the slurry was slowly adjusted to 1.4 with 28% hydrochloric acid, stirred for 1 hour, and then 22.4 g of 20% SnCl4·5H2O (an aqueous solution containing 20 mass% SnCl4·5H2O and 80 mass% water) was added at a rate of 1.0 g / min while maintaining the pH at 1.4 by the addition of 10% NaOH. After stirring this slurry for 30 minutes, 475 g of 40% TiCl4 (an aqueous solution containing 40 mass% TiCl4 and 60 mass% water) was added at a rate of 1.25 g / min while maintaining the pH at 1.4 by the addition of 35% NaOH. A 50 mL portion of the slurry was filtered to the desired pearl color, the press cake was washed with water, dried at 120 °C for 30 minutes, and calcined at 850 °C for 20 minutes. This sample was extruded for color measurement. The thickness of the first coating containing SiO2 was 50 nm, and the thickness of the second coating containing TiO2 was 30 - 50 nm. The resulting pigment had a pearl hue with improved sparkle.

[0170] Example 2 Example 2 was carried out in the same procedure as Example 1, except that 1100 g of 20% Na2SiO3·5H2O (an aqueous solution containing 20% by mass of SnCl4·5H2O and 80% by mass of water) and 455 g of 40% TiCl4 (an aqueous solution containing 40% by mass of TiCl4 and 60% by mass of water) were added. The thickness of the first coating containing SiO2 was 50 nm, and the thickness of the second coating containing TiO2 was 30 to 50 nm. The obtained pigment had a pearl hue with improved sparkle.

[0171] Example 3 Example 3 was carried out in the same procedure as Example 1, except that 1300 g of 20% Na2SiO3·5H2O (an aqueous solution containing 20% by mass of SnCl4·5H2O and 80% by mass of water) and 480 g of 40% TiCl4 (an aqueous solution containing 40% by mass of TiCl4 and 60% by mass of water) were added. The thickness of the first coating containing SiO2 was 50 to 100 nm, and the thickness of the second coating containing TiO2 was 30 to 50 nm. The obtained pigment had a pearl hue with improved sparkle.

[0172] Example 4 Example 4 was carried out in the same procedure as Example 1, except that 2000 g of 20% Na2SiO3·5H2O (an aqueous solution containing 20% by mass of Na2SiO3·5H2O and 80% by mass of water) and 425 g of 40% TiCl4 (an aqueous solution containing 40% by mass of TiCl4 and 60% by mass of water) were added. The thickness of the first coating containing SiO2 was 100 nm, and the thickness of the second coating containing TiO2 was 30 to 50 nm. The obtained pigment had a golden hue with improved sparkle.

[0173] Comparative Example 1 Comparative Example 1 was carried out in the same procedure as Example 1, except that 20% of Na2SiO3·5H2O was not added and 20% of SnCl4·5H2O in the second addition was also not added. Only the first 11.2 g of 20% SnCl4·5H2O and 555 g of 40% TiCl4 (an aqueous solution containing 40% by mass of TiCl4 and 60% by mass of water) were used in the same manner as the conventional pearl-colored effect pigment. 100 mL of the slurry was filtered, the press cake was washed with water, and calcined at 850 °C for 20 minutes. This sample was squeezed out for color measurement. The resulting pigment had a pearl color with poor sparkle.

[0174] Example 5 Example 5 was carried out in the same procedure as Example 4, except that 20% of Na2SiO3·5H2O (an aqueous solution containing 20% by mass of Na2SiO3·5H2O and 80% by mass of water) was added at 3.0 g / min, and 890 g of 40% TiCl4 (an aqueous solution containing 40% by mass of TiCl4 and 60% by mass of water) was added until the desired gold color was obtained. The calcination temperature was 825 °C. The thickness of the first coating containing SiO2 was 100 nm. The resulting pigment had an improved sparkle and a blue hue.

[0175] Comparative Example 2 Comparative Example 2 was carried out in the same procedure as Comparative Example 1, except that 970 g of 40% TiCl4 (an aqueous solution containing 40% by mass of TiCl4 and 60% by mass of water) was used in the same manner as the conventional gold-colored effect pigment. The calcination temperature was 825 °C. The resulting pigment had a gold hue with poor sparkle.

[0176] Example 6 Example 6 was carried out in the same procedure as Example 4, except that 20% Na2SiO3·5H2O (an aqueous solution containing 20% by mass of Na2SiO3·5H2O and 80% by mass of water) was added at 3.0 g / min, and 1465 g of 40% TiCl4 (an aqueous solution containing 40% by mass of TiCl4 and 60% by mass of water) was added until a desired blue color tone was obtained. The firing temperature was 825°C. The thickness of the first coating containing SiO2 was 100 nm. The obtained blue interference pigment showed stronger sparkle than Comparative Example 3.

[0177] Comparative Example 3 Comparative Example 3 was carried out in the same procedure as Comparative Example 1, except that 1480 g of 40% TiCl4 (an aqueous solution containing 40% by mass of TiCl4 and 60% by mass of water) was used in the same manner as a conventional blue color tone effect pigment. The firing temperature was 825°C. The obtained pigment had a blue hue with poor sparkle.

[0178] To determine the sparkle value and CIELab value of the pigments prepared in the above examples, a dried and cured coating film obtained by 90:10 black reduction was applied and measured as follows: The pigment was incorporated (as a 50:50 slurry of the pigment in the solvent which is part of the varnish) at a total pigment concentration of 5% by mass (based on the total mass of the wet varnish), by stirring in a conventional solvent-based medium-solids cellulose acetate butyrate (CAB) / polyester varnish (pigment / binder is 20 / 100) until the pigment was finally dispersed. The finished varnish was applied to an aluminum panel by air pressure spraying to a wet film thickness of about 150 - 160 μm, and then dried at room temperature. After drying, the base coat was overcoated with a 1K clear coat (a clear coat containing blocked isocyanate, an acrylic polymer having OH functionality, a melamine crosslinking agent, and other additives such as a UV absorber, an antioxidant, and a leveling agent), and dried and cured at 135 °C. After curing, the thickness of the base coat was about 20 μm and the thickness of the clear coat was about 40 μm. The sparkle effect of these panels was measured using a BYK-mac device (manufactured by BYK Gardner). The sparkle values (S_a, S_i, S_G) reported in Table 3 are values at an angle of 15°, clearly showing an increase in sparkle in the examples compared to the comparative examples.

[0179]

Table 3

[0180]

Table 4

[0181] Cited References: - US10214651B1 - US7699927B1 - CN108165053A - WO2008120846A1 - US7485183B1 - US8883879B1 - US8500901B1 - US10597544B1 - US20130164356B1 - US11180659B1 - US10647861B1 - EP2917285A1 - US8529876B1 - US20080279796B1 - US8268069B1 - US20200369891B1 - IN-240942 - US20170105915A1 - US20210115260A1 - CN211416537U - US20070298149B1 - EP3596170A1 - US20210087403A1 - CN109181364A - US20200339820A1

Claims

1. A method for increasing the sparkle of an effect pigment based on a transparent platelet-like substrate by applying to the substrate a near refractive index coating that matches the refractive index of the substrate, wherein the near refractive index coating comprises a material selected from the group consisting of SiO2, Al2O3, MgO, ZnO and mixtures thereof, and wherein the near refractive index coating has a thickness in the range of 30 to 170 nm.

2. The transparent plate-like substrate is made of mica, glass flakes, SiO ２ , Al ２ O ３ , BiOCl, kaolin, ZnO, BN, perlite, and mixtures thereof, preferably from the group consisting of mica, glass flakes, perlite, and mixtures thereof, more preferably the transparent plate-like substrate comprises or is mica.

3. 3. The method of claim 2, wherein the transparent plate-like substrate is a mica selected from the group consisting of muscovite (natural mica) and fluorophlogopite (synthetic mica), preferably the substrate comprises fluorophlogopite, more preferably is fluorophlogopite.

4. The method according to claim 1, wherein the refractive index of the transparent plate-like substrate is in the range of 1.0 to 2.1, preferably in the range of 1.2 to 2.0, more preferably in the range of 1.3 to 1.9, more preferably in the range of 1.4 to 1.

8.

5. 2. The method of claim 1, wherein the refractive index of the near-index coating is in the range of 1.0 to 2.1, preferably in the range of 1.2 to 2.0, more preferably in the range of 1.3 to 1.9, more preferably in the range of 1.4 to 1.

8.

6. 10. The method of claim 1, wherein the near-index coating has a refractive index within 0.3 of the substrate, preferably in the range of 0.0 to 0.29, more preferably in the range of 0.0 to 0.20, more preferably in the range of 0.0 to 0.

15.

7. The method of claim 1, wherein the near-index coating has a thickness in the range of 40 to 160 nm, more preferably in the range of 50 to 150 nm.

8. 90 to 100% by weight of the near refractive index coating, preferably 95 to 100% by weight, more preferably 98 to 100% by weight, more preferably 99 to 100% by weight, of the near refractive index coating is SiO ２ , Al ２ O ３ , MgO, ZnO, and mixtures thereof.

9. The near refractive index coating comprises a material, the material being SiO2, Al ２ O ３ and mixtures thereof, and preferably the material for the near refractive index coating is selected from the group consisting of SiO ２ and more preferably SiO ２ The method of claim 1, wherein

10. The near refractive index coating is made of two metal oxides A and B, and the two metal oxides are mixed to form the near refractive index coating, and the refractive index of the near refractive index coating is determined using the following formula: n=X Ａ ・n Ａ +X Ｂ ・n Ｂ where n is the resulting refractive index of the near refractive index coating and X Ａ is the mole fraction of metal oxide A, and n Ａ is the refractive index of metal oxide A, and X Ｂ is the mole fraction of metal oxide B, and n Ｂ is the refractive index of metal oxide B).

11. 2. The method of claim 1, wherein the transparent plate-like substrate has a Dv50 in the range of 5 to 100 microns, preferably the transparent plate-like substrate has a Dv50 of less than 30 microns, more preferably the transparent plate-like substrate has a Dv50 in the range of 5 to 30 microns, more preferably in the range of 5 to 25 microns.

12. The method of claim 1, wherein the effect pigment further comprises a combination of subsequent optical layers.

13. The subsequent optical layer is TiO ２ , Fe ２ O ３ , TiO ２ / Fe ２ O ３ , TiO ２ / SiO ２ / TiO ２ , TiO ２ / SiO ２ / Fe ２ O ３ , Fe ２ O ３ / SiO ２ / TiO ２ , and Fe ２ O ３ / SiO ２ / Fe ２ O ３ and preferably, the subsequent optical layer is selected from the group consisting of TiO ２ and Fe ２ O ３ and more preferably, the subsequent optical layer is selected from the group consisting of TiO ２ layer, more preferably TiO ２ The method of claim 12, wherein the layer is a layer.

14. The method according to claim 12 or 13, wherein each subsequent optical layer has a thickness in the range of 20 to 300 nm, preferably in the range of 20 to 180 nm, more preferably in the range of 20 to 130 nm.

15. The method of claim 1, wherein the effect pigment has a delta sparkle intensity ΔS_i in the range of 0.5 to 5.0, preferably in the range of 1.0 to 4.0, more preferably in the range of 2.0 to 3.

0.

16. The near refractive index coating is SnO ２ The method of claim 1 further comprising:

17. The method of claim 1 , wherein the near refractive index coating is applied by a method selected from the group consisting of aqueous precipitation, sol-gel, and chemical vapor deposition.

18. The method of claim 1 , wherein the applied near refractive index coating is baked before applying the additional optical layer.

19. A method of using a near refractive index coating on one or more transparent platelet-like substrates to increase the sparkle of an effect pigment composition comprising one or more transparent platelet-like substrates and a near refractive index coating that matches the refractive index of the substrates, wherein the near refractive index coating has a thickness in the range of 30 to 170 nm.

20. The use of claim 19, wherein the effect pigment composition is as defined in any one of claims 2 to 13 and 15 to 18.