Silky white multilayer coating

Abstract

The present invention relates to a multi-layer coating comprising at least one ground coat layer containing at least one non-platelet-shaped titanium dioxide pigment (T), at least one mid-coat layer on said at least one ground coat layer containing at least one platelet-shaped titanium dioxide pigment (P) selected from the group consisting of hydrogen titanium oxide (P1), fluorinated mica coated with titanium dioxide (P2) and aluminum coated with titanium dioxide (P3), and at least one clear-coat layer on the at least one mid-coat layer, the lightness L* according to CIELab being at least 80 in the viewing angle range -15° to +45°, at least 70 in the viewing angle range +75° to +110° if a metallic effect pigment is contained in the mid-coat layer, and at least 75 in the viewing angle range +75° to +110° if no metallic effect pigment is contained in the mid-coat layer. The present invention further relates to a method for producing such a multi-layer coating and to a multi-layer coated substrate.

Description

[Technical Field]

[0001] The present invention relates to multilayer coatings, methods for manufacturing the multilayer coatings, and substrates coated with the multilayer coatings. The multilayer coatings are preferably used for coating vehicles and vehicle parts, such as automobile bodies and their parts. [Background technology]

[0002] In recent years, white has become the most important color in the automotive industry in terms of the number of vehicles sold. White can be broadly divided into two main categories: those that contain platelet-shaped effect pigments and those that do not.

[0003] The first category, often referred to as "metallic" or "pearlescent" white, can contain a variety of compositions of numerous plates. These compositions are based on various substrates, such as metals, natural or synthetic mica, glass, metal oxides, silicates, and others. The plates may be coated, for example, with a (semi-)metallic oxide layer, producing the so-called "silky white" effect.

[0004] However, these multilayer coatings often exhibit a rough texture, and the polychromatic iridescent interference resulting from the coated granules is usually clearly visible. Other problems associated with the use of pigments in such granular form include the difficulty in achieving a fine, silky effect, or the fact that the color does not maintain a bright, pure white.

[0005] The most commonly used white colorants in the field of automotive coatings are titanium dioxide-based. Therefore, there is a continuously increasing demand for the provision of unique, effective formulations of titanium dioxide and titanium dioxide-based materials that can be used in the manufacture of automotive coatings.

[0006] In many cases, the commonly used titanium dioxide pigments do not move and provide the same or similar brightness values across the full viewing angle range. Other products tend to reduce the pure white appearance of the white coating by having the characteristic interference "iridescent" effect as described above, or by reducing the color brightness, or by adding an undesired hue.

[0007] The effect on color is a compositional property of titanium oxide and titanium dioxide-based effect pigments. A large particle size distribution increases the scattering of light along the edges of such flaky pigments, resulting in an obviously rough appearance. Furthermore, the effect pigments come to exhibit multiple colors that are obvious upon close observation of the coating surface, causing the "iridescent" reflection of the effect pigments.

Summary of the Invention

Problems to be Solved by the Invention

[0008] The present invention aims to provide a multilayer coating that has a slight metallic-like appearance and a bright white color, exhibits a fine and silky soft metallic-like texture effect, and on the other hand, maintains an excellent lightness L* value without excessive granularity.

Means for Solving the Problems

[0009] The above object is achieved by the following components, a) at least one ground coat layer containing at least one non-platelet-shaped titanium dioxide pigment (T), b) the following, i. at least one platelet-shaped titanium oxide pigment (P) selected from the group consisting of hydrogen titanate (P1), mica fluorinated and coated with titanium dioxide (P2), and aluminum coated with titanium dioxide (P3) in at least one mid coat layer on top of the at least one ground coat layer, and c) at least one clear coat layer on top of the at least one mid coat layer and, The following lightness L* according to CIELab In the viewing angle range from -15° to +45°, at least 80 When aluminum coated with titanium dioxide (P3) is contained in the midcoat layer, in the viewing angle range from +75° to +110°, at least 70, and When aluminum coated with titanium dioxide (P3) is not contained in the midcoat layer, in the viewing angle range from +75° to +110°, at least 75 is achieved by providing a multilayer coating having the above.

[0010] The above-mentioned multilayer coating and its preferred embodiments are hereinafter referred to as the multilayer coating according to the present invention.

[0011] The multilayer coating provided by the present invention can also be described from the viewpoint of its color characteristics. Thus, the present invention includes at least one ground coat layer, at least one midcoat layer and at least one clear coat layer, and The following lightness L* according to CIELab (i) In the viewing angle range from -15° to +45°, at least 80 (ii) When a metallic effect pigment is contained in the midcoat layer, in the viewing angle range from +75° to +110°, at least 70 (iii) When a metallic effect pigment is not contained in the midcoat layer, in the viewing angle range from +75° to +110°, at least 75, and (iv) At least 105 at a viewing angle of +15° having Granularity G of ≦2.5 and Liquid metal index LMI of ≧0.9 provides a multilayer coating.

[0012] [[ID=​​​​A further object of the present invention is a method for producing a multilayer coating, the method comprising the following steps: a. A step of applying at least one ground coat composition onto a coated or uncoated substrate to form one or more ground coat layers, wherein the ground coat composition comprises at least one non-plate-shaped titanium dioxide pigment (T), b. A step of applying at least one midcoat composition onto the sole or last groundcoat layer(s) thus formed to form one or more midcoat layers(s), wherein the midcoat composition(s) comprises at least one plate-shaped titanium oxide pigment (P) selected from the group consisting of titanium hydrogen oxide (P1), titanium dioxide-coated fluorinated mica (P2), and titanium dioxide-coated aluminum (P3), and c. The step of applying at least one clear coat composition onto the sole or last midcoat layer(s) thus formed to form one or more clear coat layers(s), and d. A process of curing the ground coat layer, midcoat layer and / or clear coat layer, which may be uncured or not yet fully cured. Includes.

[0014] The method for manufacturing the multilayer coating described above and its preferred embodiment will be referred to below as the method for manufacturing the multilayer coating according to the present invention.

[0015] Another object of the present invention is a multilayer coated substrate coated with the multilayer coating according to the present invention, which will be hereinafter referred to as the multilayer coated substrate of the present invention. [Brief explanation of the drawing]

[0016] [Figure 1] Figure 1 shows the multi-angle measurement geometry. [Figure 2] Figure 2 shows the glossiness of the three-layer coating. [Modes for carrying out the invention]

[0017] Preferred embodiments and features of the present invention are described in more detail below.

[0018] In the general context of the present invention, and particularly in relation to the coating layers and coating compositions according to the present invention, the term “comprising” has the meaning of “containing” rather than “consisting of.” In particular, “containing” means that, in addition to the layers, components, or compounds enumerated in each context, one or more further layers, components, or compounds mentioned below may be optionally contained in the multilayer coating or coating composition according to the present invention. Any component may be present in each case according to their preferred embodiments mentioned below.

[0019] The term "field of view range" here defines the specific angles within the range of -15° to +110°, i.e., the angles for which the L*, a*, and b* values ​​are determined by a commonly used measurement setup. In such a setup, the specific field of view angles are off-specular at -15°, +15°, +25°, +45°, +75°, and +110°, as shown in Figure 1. Therefore, determining the L* value in the field of view range of -15° to +45° means that the L* values ​​at the field of view angles of -15°, +15°, +25°, and +45° are determined and relevant.

[0020] The wt.-% (i.e., mass%) proportions and amounts of all essential and optionally present components of the coating composition are added up to 100% by mass relative to the total mass of each coating composition.

[0021] Any of the coating compositions described below can be prepared using conventional and known preparation and mixing methods and mixing units, and / or using conventional dissolvers and / or stirrers.

[0022] Multilayer coatings, various layers therein, and their compositions The multilayer coating of the present invention comprises or consists of at least three layers, namely at least one ground coat layer, at least one midcoat layer (hereinafter also referred to as the "basecoat layer"), and at least one clearcoat layer. Preferably, the multilayer coating of the present invention comprises or consists of one ground coat layer, one or two, preferably one basecoat layer, and one clearcoat layer.

[0023] Ground coat layers(s), midcoat layers(s), and clear coat layers(s) are formed by applying ground coat compositions(s) to a pre-coated or uncoated substrate, midcoat compositions(s) to the single or final ground coat layer, and clear coat compositions(s) to the single or final midcoat layer, respectively. When each layer is applied using multiple spray passes with the same coating composition, this is considered the formation of a single layer. Only when two or more different ground coat, midcoat, or clear coat compositions are used is it considered that two or more ground coat, midcoat, or clear coat layers are formed, respectively.

[0024] The multilayer coating of the present invention is white, that is, it produces a color impression defined by the above-mentioned L* value within the white color space. More preferably, the white color space is characterized by the following CIELab values ​​a* and b* (according to EN ISO11664-4 "Colorimetry-Part4:CIE1976 L*a*b* Colour Space", July 2011 edition, which is hereby simply referred to as CIELab) in addition to the above-mentioned essential L* value: a* is -3.8 to +3.8 and b* is -5 to +4 in the viewing angle range of -15 to +110°. Within the aforementioned range, the multilayer coating is slightly colored, and particularly preferably the ground coat layer of the multilayer coating is colored, but the impression of white given to the observer is still maintained.

[0025] The multilayer coating of the present invention preferably has the following characteristics. • A brightness (L*) value of ≥105, more preferably ≥108, and most preferably ≥110, or even ≥115, at a viewing angle of 15°, and / or • A brightness (L*) value of ≥75, more preferably ≥78, most preferably ≥80, or even ≥85 at a viewing angle of 110°, and / or • Granularity (G) ≤2.5, more preferably ≤2.2, most preferably ≤2.0, or even further ≤1.8 diff ) value, and / or • Liquid metal index (LMI) value of ≥0.9, more preferably ≥1.0, and most preferably ≥1.20.

[0026] The aforementioned preferred characteristics L* (at 15° and 110°), G diffand LMI are suitable for further characterizing and improving the multilayer coatings of the present invention, independently of each other, and can be implemented independently. Thus, the most broad embodiments of the present invention can be further improved by increasing brightness at viewing angles +15° or +110°, or by increasing the liquid metal index, or by reducing granularity, or by improving two, three, or all four properties. Particularly preferred is that the multilayer coating has a granularity value ≤ 2.5, which can be implemented, for example, as disclosed below herein.

[0027] Furthermore, the white multilayer coating preferably has a hue that is neutral to slightly bluish; that is, the b* value of the multilayer coating of the present invention is preferably ≤3, more preferably ≤1, most preferably ≤0, and even more preferably ≤-0.5 for viewing angles from -15° to 110°. In all cases, the lower limit of b* is preferably -5 for viewing angles from -15° to 110°.

[0028] Preferably, the multilayer coating of the present invention has a luminous area in the range of 4 to 16, more preferably 5 to 15, and most preferably 6 to 12, at a viewing angle of 15°, and a luminous intensity in the range of 2 to 8, more preferably 2.5 to 7, and most preferably 3 to 6, at a viewing angle of 15°.

[0029] The values ​​of L*, a*, b*, luminous area and intensity, granularity, flop index and liquid metal index are determined using a BYK Mac i spectrophotometer, as detailed in the experimental section of this invention.

[0030] The solid content of the coating composition or a portion thereof is determined by drying a sample (approximately 1 g) of the coating composition or a portion thereof at 110°C for 60 minutes. The solid content in mass percent is obtained by dividing the mass of the dried residue by the mass of the sample and multiplying by 100.

[0031] Below, we will first describe various types of layers and the coating compositions used to form them.

[0032] Groundcoat layer and groundcoat composition The ground coat layer(s) is characterized by at least one ground coat layer containing at least one non-platelet titanium dioxide pigment(T). This layer provides good opacity so that the color of the underlying uncoated or pre-coated substrate is preferably not visible.

[0033] The titanium dioxide pigment (T) used in this ground coat layer is typically a conventional titanium dioxide pigment used in the automotive coatings industry. Such non-platelet titanium dioxide pigments (T) are typically spherical or irregular in shape and rutile in form, preferably obtained by a well-known chloride process. They consist of primary particles, agglomerates, and aggregates, and are typically ground / crushed to form a pigment paste, which is used in ground coat compositions for forming the ground coat layer.

[0034] The titanium dioxide pigment (T) may contain small amounts of other metal oxides, such as alumina, or metalloid oxides, such as silicon dioxide. In such cases, the titanium dioxide pigment typically functions as a core particle, and the various metal oxides and metalloid oxides precipitate on the pigment surface to adopt properties, such as better wettability. However, the titanium dioxide content of such a pigment is preferably at least 90% by mass, and more preferably at least 92% by mass, relative to the total mass of the pigment.

[0035] Such titanium dioxide (T) is used in the production of ground coat compositions and preferably has a median primary particle diameter in the range of 200-500 nm, more preferably 300-400 nm, determined by dynamic light scattering using a Malvern Zetasizer (Malvern, S90 unit, Nanoseries Model ZEN 1690mfg 5 / 2017). This method determines the Z-mean particle diameter and volume-based D 10 , D 50 and D 90 This is used throughout the description of how the values ​​are determined. Further details can be found in the experimental section of this specification.

[0036] Such titanium dioxide pigments (T) are, for example, available from Chemour's Ti-Pure 商標 It is sold under the product names Kronos2310 by Kronos, CR510 by Citic Titanium, and Tiona596 by Cristal.

[0037] The preferred dry layer thickness of the ground coat layer or the stack of ground coat layers is in the range of 8 to 20 μm, more preferably 12 to 18 μm.

[0038] The dry layer thickness of any coating layer in the multilayer coating of the present invention can be determined as described in the experimental section of the present invention.

[0039] The ground coat layer(s) is formed by applying a ground coat composition containing one or more of the above-mentioned non-plate-shaped titanium dioxide pigments onto an uncoated or pre-coated substrate.

[0040] Ground coat compositions are typically selected from one-component and two-component compositions, which are either aqueous or solvent-based.

[0041] The following is effective for any coating composition (ground coat composition, mid coat composition, and clear coat composition). A coating composition is classified as an aqueous or water-based coating composition if its main volatile component is water, and as a solvent-based or solvent-system coating composition if its main volatile component is an organic solvent or a mixture of organic solvents. Volatile components are defined as the difference between the total mass of the coating composition and its solid content. Suitable solvents for solvent-system coating compositions are listed below under the heading "Solvents (S) for Use in Ground Coat, Mid Coat, and Clear Coat Compositions".

[0042] In this case, it is preferable to use an aqueous, one-component composition as the ground coat composition.

[0043] Preferably, the solid content of the aqueous ground coat composition according to the present invention is in the range of 25 to 55% by mass, more preferably 27 to 50% by mass, most preferably 35 to 45% by mass, and particularly 37 to 42% by mass.

[0044] Preferably, the solid content of the solvent-based ground coat composition according to the present invention is in the range of 30 to 80% by mass, more preferably 40 to 70% by mass, most preferably 50 to 68% by mass, and particularly 55 to 66% by mass.

[0045] In addition to the non-plate-shaped titanium dioxide pigment (T) described above, the ground coat composition includes at least one film-forming polymer (A1), a crosslinking agent (A2) if (A1) is externally crosslinkable, optionally one or more dyes (B1), pigments (B2) and / or fillers (B3) different from the non-plate-shaped titanium dioxide pigment (T), a solvent component (S), and further optional components (C), such as typical coating additives, such as rheological additives. These aforementioned components of the ground coat composition may also be used in one or more other coating compositions (midcoat compositions and clearcoat compositions), which will be further described in another part of the following description.

[0046] Midcourt layer and midcourt composition The terms “midcoat layer” and “midcoat composition” are known in the art and are often also referred to as “basecoat layer” and “basecoat composition,” respectively. The term “basecoat” is defined, for example, in Roempp Lexikon, “Lacke und Druckfarben” ("Paints and “Printing Inks"), Georg Thieme Verlag, 1998, 10th edition, p. 57. Accordingly, the basecoat or midcoat as named herein is used particularly in the coloring of automotive coatings and general industrial paints to produce coloring and / or optical effects by using a basecoat / midcoat composition as an intermediate coating composition. The basecoat / midcoat composition is generally applied to a metal or plastic substrate that has been optionally pre-coated with a pretreatment and / or groundcoat composition, and in this application is applied at least on a groundcoat layer.

[0047] The midcoat layer(s) of the present invention is formed by applying one or more midcoat compositions onto the sole or final groundcoat layer. The midcoat layer(s) of the present invention comprises at least one plate-shaped titanium oxide pigment(P) selected from the group consisting of titanium hydrogen oxide(P1), titanium dioxide-coated fluorinated mica(P2), and titanium dioxide-coated aluminum(P3).

[0048] Small plate-shaped titanium dioxide pigment (P) The term "plate-shaped" is a commonly used term in the field of coatings, referring to the plate-like shape of effect pigments, and is used to characterize the term "effect pigment" in DIN EN ISO 4618:215-01. Such pigments typically have a high aspect ratio (average particle length / average particle thickness). The plate-shaped pigments used in this invention are preferably flake-shaped pigments.

[0049] All of the following three types of pigments (P1), (P2), and (P3) preferably provide a blue shift (a "shift") at various angles and tend to increase brightness near the specular viewing angle (+15°). In principle, the inventors have found that larger-sized pigments add more brightness, while smaller-sized pigments reduce grains.

[0050] Hydrogen titanate (P1) Platelet-shaped, particularly flake-shaped hydrogen titanate pigments (P1) and their production are described, for example, in EP2007598A1 and EP3753903A1 as flaky titanic acid, in US2021 / 0047517 or Chem. Mater. 2018, 30, 1505 - 1516. Regarding these products, the formula H2Ti3O7 or H 4x / 3 Ti 2-x / 3 O4 . nH2O is often referred to, where x is 0.50 - 1.0 and n is 0 - 2. The product may contain bound water of crystallization, which is considered part of the pigment if present.

[0051] Such hydrogen titanate pigments (P1) are used in the production of midcoat compositions and preferably have a volume-based D 50 average particle size in the range of 5 - 50 μm, more preferably 8 - 4 μm, and most preferably 10 - 35 μm, which are determined by the dynamic light scattering method using the same methods and apparatus as described above and in the experimental section of this specification, and preferably have a platelet thickness in the range of 50 - 150 nm, more preferably 70 - 130 nm, and most preferably 90 - 110 nm, which are determined by the electron microscopy method detailed in the experimental section of this specification. The platelet thickness of any platelet-shaped pigment used in the present invention can be determined by this method.

[0052] These titanium hydrogen oxides add color variation to multilayer coatings in the white color space, while simultaneously reducing the iridescent effect described for prior art coatings, and adding brightness and a bluish hue near the off-specular range (-15° and +15°), thus providing a purer white impression at these angles.

[0053] These titanium oxide (P1) pigments are commercially available, for example, from Ishihara Sangyo Co., Ltd. under the name LPT-106.

[0054] When present in a midcoat composition, the mass ratio of titanium hydrogen oxide (P1) to the total of the film-forming polymer (A1) and crosslinking agent (A2), i.e., (P1) / [(A1)+(A2)], is preferably in the range of 0.01 to 0.5, more preferably 0.05 to 0.4, and most preferably 0.1 to 0.3.

[0055] Titanium dioxide-coated fluorinated mica (P2) The term "fluorinated mica" or "fluorine mica" refers to synthetic mica, in which the OH group in each mica formula is replaced with a fluorine group.

[0056] The fluorinated mica (P2) coated with titanium dioxide in a plate-like shape is a synthetic mica coated with titanium dioxide, and is particularly preferably a synthetic fluorophlogopite coated with titanium dioxide.

[0057] Natural mica is mined in the presence of sand, kaolin, feldspar, and other silicates, and may contain various impurities, such as iron oxides and heavy metals. Synthetic mica, however, does not contain such impurities. Due to the presence of these additional impurities, natural mica is often discolored. This discoloration is, of course, an undesirable characteristic of the natural material, especially when mica is used as a slab, core, or substrate for pigments, particularly in paints in the white color space.

[0058] Furthermore, natural mica must be ground to produce flakes. This grinding process does not allow for precise control over the smoothness of the mica surface, the stepped characteristics of the flakes, and their thinness. Therefore, the flakes often have imperfect edges and faces, and lower specular reflection (edge ​​scattering). Consequently, the mining and grinding of natural mica is not suitable for producing large-diameter, thin flakes that result in small plates with a high aspect ratio.

[0059] Therefore, synthetic fluorine-containing mica can be synthesized, for example, as described in US2014 / 0251184A1, or using the Bridgman-Stockbarger method with a seeded platinum crucible. Fluorphlogopite, in particular, is a widely used pigment with the formula KMg3AlSi3O 10 It has F2. This fluorinated mica is of paramount importance in this invention and is often used in cosmetic formulations.

[0060] In this invention, fluorinated mica, particularly preferably fluorophlogopite, is used, which is covered or coated with titanium dioxide. A method for coating synthetic mica with titanium dioxide, for example, is disclosed in EP3719081A1, but this is also a cutting-edge technology, as most mica products on the market are coated with metal oxides of various compositions.

[0061] The titanium dioxide-coated fluorinated mica (P2) used here preferably contains only titanium dioxide as the coating. However, small amounts of other oxides in the coating, such as tin oxide, are also acceptable. Furthermore, depending on the grade, silane may be included as a surface modifier in an amount of preferably 0 to 3% by mass relative to the total mass of the pigment (P2).

[0062] In fluorinated mica (P2) coated with titanium dioxide, the mass ratio of titanium dioxide to fluorinated mica is preferably in the range of 3:7 to 7:3, more preferably 3.5:6.5 to 6.5:3.5, or 4:6 to 6:4, relative to the total mass of the titanium dioxide coating on the fluorinated mica and the fluorinated mica itself.

[0063] When present in a midcoat composition, the mass ratio of fluorinated mica (P2) coated with plate-shaped titanium dioxide to the total mass of film-forming polymer (A1) and crosslinking agent (A2), i.e., (P2) / [(A1)+(A2)], is preferably in the range of 0.01 to 0.5, more preferably 0.05 to 0.3, and most preferably 0.1 to 0.28.

[0064] Such titanium dioxide-coated fluorinated mica (P2) is used in the production of midcoat compositions, preferably in a volume-based D 50 The average particle size is in the range of 2 to 40 μm, more preferably 3 to 30 μm, and most preferably 5 to 20 μm, for example, in the range of 5 to 15 μm, which are determined by the dynamic light scattering method described in the experimental section of this specification, and the small plate thickness is 50 nm to about 400 nm, as determined by the electron microscopy method described in the experimental section of this specification.

[0065] In this invention, these pigments have been found to reduce granularity, contribute to brightness, and enable neutral or bluer hues. In particular, D less than 10 50 Fluorinated mica (P2) coated with smaller-sized titanium dioxide, which has a specific value, reduces granularity and results in a more linear color (i.e., non-metallic) appearance. 50 Values ​​of 10 or higher result in a brighter appearance (L* value), especially around specular reflection (+15°), but increase granularity.

[0066] Aluminum coated with titanium dioxide (P3) Aluminum coated with small, plate-shaped titanium dioxide (P3) belongs to the group of "metallic effect pigments."

[0067] The term "metallic effect pigment" is used in accordance with EN ISO 18451-1:2019 (Pigments, dyes and extenders - Terminology - Part 1). A metallic effect pigment is defined as a pigment in the form of a small plate made of metal. In this invention, the term "made of metal" includes the presence of a surface coating of the metallic effect pigment, i.e., a titanium dioxide layer on the aluminum effect pigment. However, this does not preclude the presence of a small amount, preferably less than 5% by mass relative to the mass of the titanium dioxide-coated aluminum (P3), of further metal oxides or metalloids in the coating applied to the aluminum. The aluminum effect pigment (P3) may be treated with other agents (e.g., functional silanes) to stabilize the pigment against the reaction and uptake of moisture, which may cause deterioration of the coating properties.

[0068] The inventors have found that these titanium dioxide-coated aluminum pigments (P3) provide a slight metallic appearance and impart a higher flop index, i.e., an improved metallic effect, to multilayer coatings, as well as adding a bluish tint. Since these pigments (P3) are preferably present in small amounts, they do not provide the typical overall metallic appearance of metallic coatings known in the art, but they can give a slight metallic impression to a linearly toned white appearance. Because the presence of these pigments leads to a darker flop at a viewing angle of +110°, they are used only in low amounts to maintain the L* value within a given range in the white color space.

[0069] Aluminum coated with titanium dioxide (P3) in this manner is used in the production of midcoat compositions, preferably in a volume-based D 50The average particle size is in the range of 5 to 20 μm, more preferably 6 to 15 μm, and most preferably 7 to 12 μm, which are determined by dynamic light scattering methods as described in the experimental section of this specification, and the plate thickness is 50 to 200 nm as determined by electron microscopy as described in the experimental section of this specification.

[0070] Several metal-like pigments coated with (semi-)metallic oxides are known in the art. A method for producing aluminum pigments coated with titanium dioxide has already been disclosed, for example, in U.S. Patent No. 5,026,429, issued in the 1990s.

[0071] When present in a midcoat composition, the mass ratio of titanium dioxide-coated aluminum pigment (P3) to the total of the film-forming polymer (A1) and crosslinking agent (A2), i.e., (P3) / [(A1)+(A2)], is preferably in the range of 0.001 to 0.2, more preferably 0.002 to 0.15, and most preferably 0.003 to 0.1.

[0072] Titanium dioxide pigment (T*) in an optional but preferred non-plate shape. Particularly preferred is that the midcoat composition contains, in addition to plate-shaped titanium dioxide pigment (P), at least one non-plate-shaped titanium dioxide pigment (T*). This non-plate-shaped titanium dioxide pigment may further contain varying amounts of other metal oxides, such as zirconium dioxide or aluminum dioxide and / or metal hydroxides, such as zirconium hydroxide and aluminum hydroxide. Preferably, a combination of zirconium dioxide and aluminum hydroxide. A typical amount of titanium dioxide in such a non-plate-shaped titanium dioxide pigment (T*) is at least 80% to 100% by mass relative to the total mass of the non-plate-shaped titanium dioxide pigment (T*). If other metal oxides and / or metal hydroxides are present, their combined amount may be 20% by mass or less, preferably less than 15% by mass, and more preferably less than 10% by mass, relative to the mass of the non-plate-shaped titanium dioxide pigment (T*). Most preferably, the non-plate-shaped titanium dioxide pigment (T*) contains at least 85% by mass of titanium dioxide, less than 10% by mass, more preferably less than 8% by mass of aluminum hydroxide, and less than 5% by mass, more preferably less than 3% by mass of zirconium dioxide, where any percentage is relative to the total mass of the non-plate-shaped titanium dioxide pigment (T*). Preferably, such a pigment has a primary particle size in the range of 10 to 50 nm, more preferably 20 to 40 nm, for example, 25 to 35 nm. Such pigments are commercially available, for example, TTO-55A, TTO-55D, TTO-51A, and TTO-51C from Tayca Corporation or Ishihara.

[0073] The non-plate-shaped titanium dioxide pigments (T*) described above typically have a low primary particle size, but commercially available products contain aggregates and agglomerates of primary particles, resulting in a non-uniform mixture of these particles, thus creating a large particle size distribution span [(D 90 -D 10 ) / (D 50 )] and have a high Z-mean particle diameter, which is much higher than the nominal primary particle diameter.

[0074] Therefore, any non-plate-shaped titanium dioxide pigment (T*) is preferably finely ground to have an even lower particle size than commercially available products.

[0075] Such titanium dioxide pigments (T*) can preferably be used as colloidal dispersions containing titanium dioxide particles (T*) having a Z-average particle size in the range of 30 nm to 220 nm, as determined by dynamic light scattering, and a particle size distribution span in the range of 0.7 to 1.5. Such dispersions further comprise one or more dispersants having groups that bind to the titanium dioxide particles. Such dispersions of finely ground titanium dioxide pigments (T*) can be obtained by first forming a premix comprising one or more unground titanium dioxide pigments (T*) having a Z-average particle size of >220 nm and / or a particle size distribution span of >1.5, as determined by dynamic light scattering, and one or more dispersants having groups that bind to one or more titanium dioxide pigments; and then grinding the premix obtained in the first step using a bead mill or shaker mill until titanium dioxide particles having a Z-average particle size in the range of 30 nm to 220 nm, as determined by dynamic light scattering, and a particle size distribution span in the range of 0.7 to 1.5 are obtained. D is used to determine the average particle size of Z and to calculate the particle size distribution span. 10 , D 50 and D 90 The value can be determined by dynamic light scattering using a Malvern Zetasizer (Malvern, S90 unit, Nanoseries Model ZEN 1690mfg 5 / 2017), as described in the experimental section of this invention.

[0076] Non-platelet titanium dioxide pigment (T*) can be used advantageously in the present invention, particularly when it is finely ground as described above. It can be used to reduce granularity at a distant off-specular viewing angle (+110°) and contribute to a bluish hue. When it is desired to remain in a linear white tone rather than a high metallic migration, it can provide any whiter and brighter L* at 110°. However, when a large L* is desired at an angle of +15°, non-platelet titanium dioxide pigment (T*) should not be used, or only in small amounts.

[0077] The preferred dry layer thickness of the midcoat layer or midcoat layer stack is in the range of 3 to 20 μm, more preferably 4 to 15 μm, even more preferably 5 to 10 μm, for example, 6 to 8 μm.

[0078] The midcoat layer(s) is formed by applying a midcoat composition containing one or more of the above-mentioned small plate-shaped titanium oxide pigments (P).

[0079] The midcoat composition is typically selected from one-component and two-component compositions. It is preferably an aqueous one-component composition.

[0080] When present in the midcoat composition, the non-platelet titanium dioxide pigment (T*) is present in an amount ranging from 0.01 to 2.0% by mass, more preferably from 0.05 to 1.5% by mass, and most preferably from 0.1 to 1.0% by mass, relative to the total mass of the midcoat composition.

[0081] When present in a midcoat composition, the mass ratio of non-platelet titanium dioxide pigment (T*) to the total of the film-forming polymer (A1) and crosslinking agent (A2), i.e., (T*) / [(A1)+(A2)], is preferably in the range of 0.001 to 0.2, more preferably 0.003 to 0.1, and most preferably 0.004 to 0.08.

[0082] Preferably, the midcoat layer(s) and midcoat composition(s) include at least two plate-shaped titanium oxide pigments (P) selected from the group consisting of titanium hydrogen oxide (P1), titanium dioxide-coated fluorinated mica (P2), and titanium dioxide-coated aluminum (P3).

[0083] More preferably, the midcoat layer(s) and midcoat composition(s) include at least one plate-shaped titanium hydrogen oxide (P1) and at least one plate-shaped fluorinated mica (P2) coated with titanium dioxide, or at least one non-plate-shaped titanium dioxide pigment (T*) and at least one plate-shaped titanium oxide (P) selected from the group consisting of titanium hydrogen oxide (P1) and fluorinated mica (P2) coated with titanium dioxide.

[0084] More preferably, the midcoat layer(s) and midcoat composition(s) include aluminum (P3) coated with at least one plate-shaped titanium dioxide, at least one non-plate-shaped titanium dioxide pigment (T*), and additionally at least one plate-shaped titanium hydrogen oxide (P1) and / or fluorinated mica (P2) coated with at least one plate-shaped titanium dioxide.

[0085] Midcoat compositions are typically selected from one-component and two-component compositions and can be aqueous or solvent-based.

[0086] In this case, it is preferable to use an aqueous one-component composition as the midcoat composition.

[0087] Preferably, the solids content of the aqueous midcoat composition according to the present invention is in the range of 15 to 30% by mass, more preferably 16 to 27% by mass, most preferably 17 to 25% by mass, and particularly 18 to 23% by mass.

[0088] Preferably, the solid content of the solvent-based midcoat composition according to the present invention is in the range of 30 to 70% by mass, more preferably 40 to 60% by mass, most preferably 45 to 58% by mass, and particularly 50 to 55% by mass.

[0089] In addition to the plate-shaped titanium dioxide pigments (P) and non-plate-shaped titanium dioxide pigments (T*) described above, the midcoat composition includes at least one film-forming polymer (A1), a crosslinking agent (A2) if (A1) is externally crosslinkable, optionally one or more dyes (B1), pigments (B2) and / or fillers (B3) different from the plate-shaped titanium dioxide pigments (P1), (P2) and (P3), a solvent component (S), and further optional components (C), such as typical coating additives, such as rheological additives. These aforementioned components of the midcoat composition may also be used in one or more other coating compositions (e.g., ground coat compositions and clear coat compositions), which will be further described in another part of the following description.

[0090] Clear coat layer and clear coat composition The clear coat layer(s) of the multilayer coating of the present invention is formed by applying one or more clear coat compositions onto the single or final midcoat layer. The clear coat composition to be applied can be a one-component or two-component composition and can be aqueous or solvent-based. Preferably, the clear coat composition of the present invention is a solvent-based two-component composition.

[0091] The clear coat composition preferably comprises at least one binder, and more preferably comprises at least one polymer as the binder.

[0092] Preferably, the clear coat composition comprises at least one polymer having an average of two or more OH groups and / or amino groups and / or carbamate groups, more preferably OH groups and / or carbamate groups, most preferably OH groups. Preferably, at least one, preferably at least OH- and / or carbamate-functionalized polymer has a mass-average molecular weight M, preferably in the range of 800 to 100,000 g / mol, more preferably in the range of 1,000 to 75,000 g / mol, as measured by gel permeation chromatography (GPC) against a polystyrene standard. w It has.

[0093] When the clear coat composition is formulated as a two-component coating composition, it preferably contains at least one polyisocyanate having free NCO groups as a crosslinking agent. When the clear coat composition is formulated as a one-component coating composition, it preferably contains at least one polyisocyanate having blocked NCO groups and / or at least one melamineformaldehyde resin as a crosslinking agent.

[0094] Polyisocyanates suitable for use as crosslinking agents have, on average, two or more NCO groups.

[0095] Such crosslinking agents preferably have an alicyclic structure and / or parent structure derived from an alicyclic polyisocyanate by trimerization, dimerization, urethane formation, biuret formation, uretdione formation and / or allophanate formation. Alternatively or additionally, at least one crosslinking agent preferably has an acyclic aliphatic structure and / or parent structure derived from an acyclic aliphatic polyisocyanate by trimerization, dimerization, urethane formation, biuret formation, uretdione formation and / or allophanate formation. The acyclic aliphatic polyisocyanate (which optionally acts as the parent structure) is a known, preferably substituted or unsubstituted, aliphatic polyisocyanate. Examples include tetramethylene 1,4-diisocyanate, hexamethylene 1,6-diisocyanate, 2,2,4-trimethylhexane 1,6-diisocyanate, ethylene diisocyanate, dodecane 1,12-diisocyanate, and mixtures of the aforementioned polyisocyanates. The alicyclic polyisocyanate (which optionally acts as the parent structure) is a known, preferably substituted or unsubstituted, alicyclic polyisocyanate. Examples of preferred polyisocyanates include isophorone diisocyanate, cyclobutane 1,3-diisocyanate, cyclohexane 1,3-diisocyanate, cyclohexane 1,4-diisocyanate, methylcyclohexyl diisocyanate, hexahydrotoluene 2,4-diisocyanate, hexahydrotoluene 2,6-diisocyanate, hexahydrophenylene 1,3-diisocyanate, hexahydrophenylene 1,4-diisocyanate, perhydrodiphenylmethane 2,4'-diisocyanate, 4,4'-methylenedicyclohexyl diisocyanate (e.g., Desmodur® W from Bayer AG), and mixtures of the aforementioned polyisocyanates. Crosslinking agents having an average of two or more NCO groups can also be partially silanized with hydrolyzable silanes. Such silane-based crosslinking agents are disclosed, for example, in WO2010 / 063332A1, WO2010 / 139375A1, and WO2009 / 077181A1.

[0096] In particular, if the clear coat composition is a two-component coating composition, it is most preferably a solvent-based clear coat composition. This is because free NCO groups and optionally contained hydrolyzable silanes in aqueous compositions can cause undesirable premature reactions with water.

[0097] A particularly suitable crosslinking agent when the clear coat composition is formulated as a one-component coating composition is melamine formaldehyde resin.

[0098] The clear coat composition may use the above-mentioned film-forming polymer and crosslinking agent, but is not limited to these. Therefore, in addition to the above components, the clear coat composition may include a film-forming polymer (A1), a crosslinking agent (A2) if (A1) is externally crosslinkable, a solvent (S), and one or more further optional components (C), such as typical coating additives and rheological additives as described later. Typically, the clear coat composition does not contain opacifying pigments and / or fillers, or more preferably, does not contain any pigments and / or fillers. However, in some cases, the clear coat composition may contain pigments if the pigment results in very low haze or is transparent. Such pigments may be, for example, finely ground titanium dioxide pigment T* as described above.

[0099] Preferably, the total solids content of the clear coat composition is in the range of 10 to 65% by mass, more preferably 15 to 60% by mass, even more preferably 20 to 50% by mass, and particularly 25 to 45% by mass, based on the total mass of the clear coat composition in each case.

[0100] The clear coat layer(s) formed from the clear coat composition(s) preferably has a dry film thickness in the range of 20 to 60 μm, more preferably 30 to 50 μm, and even more preferably 35 to 45 μm.

[0101] Film-forming polymer (A1) for use in ground coat, midcoat, and clear coat compositions. The ground coat and midcoat compositions of the present invention each contain at least one film-forming polymer as a film-forming binder (A1) of each composition.

[0102] For the purposes of the present invention, term (A1) is understood to be a non-volatile component of the coating composition that causes film formation, excluding additives, and in particular excluding further additives (C). Preferably, at least one polymer of at least one polymer (A1) is the main binder of the coating composition. As the main binder in the present invention, the binder component preferably refers to one that is present in a higher proportion of the total mass of the coating composition than other binder components would be present in the coating composition.

[0103] The term "polymer" is known to those skilled in the art and, for the purposes of this invention, encompasses polyadditives, polymers, and polycondensates. The term "polymer" includes both homopolymers and copolymers.

[0104] At least one polymer used as component (A1) may be physically drying, self-crosslinking, or externally crosslinking. Suitable polymers that can be used as component (A1) are described, for example, in EP0228003A1, DE4438504A1, EP0593454B1, DE19948004A1, EP0787159B1, DE4009858A1, DE4437535A1, WO92 / 15405A1, and WO2005 / 021168A1.

[0105] The at least one polymer used as component (A1) is preferably selected from the group consisting of polyurethane, polyurea, polyester, polyamide, poly(meth)acrylate, and / or copolymers of the structural units of the said polymer, particularly polyurethane-poly(meth)acrylate and / or polyurethane-polyurea. The at least one polymer used as component (A1) is particularly preferably selected from the group consisting of polyurethane, polyester, poly(meth)acrylate, and / or copolymers of the structural units of the said polymer. In the context of the present invention, the terms “(meth)acrylic” or “(meth)acrylate” each include, in each case, the meanings of “methacrylic” and / or “acrylic,” or “methacrylate” and / or “acrylate.”

[0106] Preferred polyurethanes are described, for example, on pages 4, line 19 to 11, line 29 (polyurethane prepolymer B1) of German patent application DE19948004A1, on pages 3, line 24 to 5, line 40 of European patent application EP0228003A1, on pages 38 to 8, line 9 of European patent application EP0634431A1, and on pages 2, line 35 to 10, line 32 of International patent application WO92 / 15405.

[0107] Preferred polyesters are described, for example, in columns 6, row 53 to 7, row 61 and columns 10, row 24 to 13, row 3 and Example D of DE4009858A1, or in pages 2014 / 033135A2, pages 2, row 24 to 7, row 10 and pages 28, row 13 to 29, row 13. Similarly, polyesters may have a dendritic structure, for example, as described in WO2008 / 148555A1.

[0108] Preferred polyurethane-poly(meth)acrylate copolymers (e.g., (meth)acrylated polyurethanes) and their preparations are described, for example, on pages 3, lines 21 to 20, line 33 of WO91 / 15528A1 and on pages 2, lines 27 to 6, line 22 of DE4437535A1.

[0109] Preferred poly(meth)acrylates can be prepared by multi-step free-radical emulsion polymerization of olefinic unsaturated monomers in water and / or organic solvents. Seed-core-shell polymers (SCS polymers) are particularly preferred, for example. Such polymers or aqueous dispersions containing such polymers are known, for example, from WO2016 / 116299A1.

[0110] A preferred polyurethane-polyurea copolymer is a polyurethane-polyurea particle having an average particle size of 40 to 2000 nm, wherein each polyurethane-polyurea particle contains, in a reacted form, at least one isocyanate group-containing polyurethane prepolymer containing an anionic group and / or a group convertible to an anionic group, and at least one polyamine containing two primary amino groups and one or two secondary amino groups. Preferably, such copolymers are used in the form of aqueous dispersions. Such polymers can, in principle, be prepared by conventional polyaddition of polyisocyanates with polyols and polyamines, for example.

[0111] The polymer used as component (A1) preferably has a reactive functional group that enables a crosslinking reaction. Any common crosslinkable reactive functional group known to those skilled in the art may be present. Preferably, the polymer used as component (A1) has at least one functional reactive group selected from the group consisting of primary amino groups, secondary amino groups, hydroxyl groups, thiol groups, carboxyl groups, and carbamate groups. Preferably, the polymer used as component (A1) has a functional hydroxyl group.

[0112] Preferably, the polymer used as component (A1) is hydroxy-functional and more preferably has an OH value in the range of 10 to 500 mg KOH / g, more preferably 40 to 200 mg KOH / g.

[0113] The polymer used as component (A1) is particularly preferably a hydroxy-functional polyurethane-poly(meth)acrylate copolymer, a hydroxy-functional polyester, and / or a hydroxy-functional polyurethane-polyurea copolymer.

[0114] Furthermore, the coating composition of the present invention may contain at least one typical crosslinking agent known on its own. The crosslinking agent (A2) should be included in the film-forming non-volatile components of the coating composition and is therefore included in the general definition of “binder”.

[0115] The amount of film-forming polymer (A1) in the ground coat or mid coat composition is preferably in the range of 20 to 45% by mass, more preferably 25 to 35% by mass, relative to the total mass of the coating composition.

[0116] Crosslinking agent (A2) for use in ground coat, midcoat, and clear coat compositions If (A1) is externally crosslinkable, a crosslinking agent (A2) is required for crosslinking, which is preferably at least one aminoplast resin and / or at least one blocked or free, preferably blocked polyisocyanate, and most preferably an aminoplast resin. Among aminoplast resins, melamine resins such as melamine-formaldehyde resins are particularly preferred.

[0117] The amount of crosslinking agent (A2) in the ground coat or mid coat composition is preferably in the range of 3 to 20% by mass, more preferably 4 to 10% by mass, relative to the total mass of the coating composition.

[0118] Further dyes (B1), pigments (B2), and fillers (B3) for use in ground coat, midcoat, and clear coat compositions. The ground coat, mid coat, and clear coat compositions of the present invention, preferably only the ground coat composition of the present invention, may further contain a colorant and / or filler, the colorant being selected from the group consisting of dyes (B1) and coloring and / or effect pigments (B2), excluding the pigments (P), (T), and (T*) described above. In this context, "excluding" means that pigments (P), (T), and (T*) may certainly be present, but are simply excluded from the definition of pigment (B). Therefore, for example with regard to calculating quantities, pigments (P), (T), and (T*) are not included in pigment (B).

[0119] The term "dyes" (B1) (also called dyes) refers to colorants that are soluble in the surrounding medium, as opposed to pigments. Suitable dyes are organic or inorganic. It is not recommended to use any soluble dyes in any of the coating layers of the present invention, because soluble dyes can alter the color to deviate from the white color space, as defined above. Therefore, the coating layers of the present invention preferably do not contain dyes (B1). If dyes (B1) are used, they are preferably small amounts of blue dye.

[0120] The term "pigment" is used for color pigments (B2), but pigment (P) also refers to colorants, which, in contrast to dyes, are essentially insoluble in the surrounding medium. This term includes color pigments and effect pigments. Those skilled in the art are familiar with the term effect pigment. A corresponding definition can be found, for example, in Roempp Lexikon, Lacke und Druckfarben, Georg Thieme Verlag, 1998, 10th edition, pp. 176 and 471.

[0121] Those skilled in the art are familiar with the concept of color pigments. The terms "coloring pigment" and "color pigment" are interchangeable. Inorganic and / or organic pigments can be used as color pigments. Preferably, the color pigment is an inorganic color pigment. Particularly preferred color pigments to be used are white pigments, colored pigments and / or black pigments. Examples of white pigments are titanium dioxide pigment, white zinc, zinc sulfide and lithopone. Examples of black pigments are carbon black, iron manganese black and spinel black. Examples of colored pigments are chromium oxide, chromium oxide hydrate green, cobalt green, ultramarine green, cobalt blue, ultramarine blue, manganese blue, ultramarine violet, cobalt and manganese violet, iron oxide red, molybdate red and ultramarine red, iron oxide brown, mixed brown, spinel and corundum phase and chromium orange, iron oxide yellow, nickel titanium yellow, chromium titanium yellow, cadmium sulfide, cadmium zinc sulfide, chromium yellow and bismuth vanadate.

[0122] It is not recommended to use any color pigment (B2) in any of the coating layers of the present invention, especially if it is not white or blue, because they may change color to deviate from the white color space as defined above. Therefore, the coating layers of the present invention preferably do not contain pigment (B2). If pigment (B2) is used, it is preferably a small amount of blue dye. When used in small amounts, blue pigment (B2) adds a purer white appearance, especially in the ground coat layer and, less preferably, in the midcoat layer. Particularly preferred are inorganic blue pigments, such as spinel-type pigments, such as cobalt aluminate spinel-type blue pigments.

[0123] Further examples of effect pigments, in addition to the essential pigments (P1), (P2), and / or (P3), include plate-shaped metallic effect pigments different from the aforementioned pigments (P), such as gold bronze, flame bronze, and / or iron oxide-aluminum pigments, pearlescent pigments, glass pigments, silica pigments, and / or natural mica pigments. Any of these plate-shaped effect pigment flakes may be coated with additional compounds to provide absorption or interference-type color behavior. The coating of the plates may be a metal oxide or an organic colorant.

[0124] The term “filler” (C3) is known to those skilled in the art, for example, from DIN 55943 (dated October 2001). For the purposes of the present invention, “filler” is understood to mean a substance that is essentially insoluble in a coating medium, e.g., a coating composition according to the present invention, and is used in particular to increase volume. In the context of the present invention, “filler” preferably has a refractive index different from that of “pigment,” with fillers being <1.7 and pigments being ≥1.7. Examples of suitable fillers include kaolin, dolomite, calcite, chalk, calcium sulfate, barium sulfate, talc, silicic acid, especially pyrogenated silicic acid, hydroxides such as aluminum hydroxide or magnesium hydroxide, glass flakes, or organic fillers, e.g., textile fibers, cellulose fibers and / or polyethylene fibers; see, additionally, Roempp Lexikon Lacke und Druckfarben, Georg Thieme Verlag, 1998, pp. 250 et seq., “Fillers”.

[0125] As described above, the colorants (B1) and (B2) and the filler (B3) are all different from the pigments (P), (T), and (T*). If present, (B1), (B2), and (B3) may be included in the ground coat composition and / or the mid coat composition, but if present, they are preferably included only in the ground coat composition.

[0126] In particular, the total amount and type of coloring dyes (B1) and / or coloring or coloring and effect-imparting pigments (B2) and / or coloring fillers (B3) are selected to give just a light tint to the overall white impression of the multilayer coating while maintaining a white impression within the above-defined range of L* values ​​specified for the multilayer coating of the present invention.

[0127] Solvent (S) for use in ground coat, mid coat, and clear coat compositions. The ground coat and midcoat compositions contain water and / or one or more organic solvents as component (S).

[0128] The total amount of water and organic solvents present in the coating composition is the difference between the total mass of the composition and its solid content, and is also called "volatile content."

[0129] When a ground coat composition and a midcoat composition primarily contain water as part of their volatile components, they are named aqueous or water-based ground coat or midcoat composition. This is preferable for ground coat compositions and midcoat compositions.

[0130] Any conventional organic solvent known to those skilled in the art can be used as the organic solvent for the preparation of the coating compositions of the present invention. The term “organic solvent” is known to those skilled in the art, in particular from Council Directive 1999 / 13 / EC of March 11, 1999. Preferably, one or more organic solvents are selected from the group consisting of monohydric or polyhydric alcohols, e.g., methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-ethylhexanol, ethylene glycol, ethyl glycol, propyl glycol, butyl glycol, butyl diglycol, 1,2-propanediol and / or 1,3-propanediol, ethers, e.g., diethylene glycol dimethyl ether, aliphatic hydrocarbons, aromatic hydrocarbons, e.g., toluene and / or xylene, ketones, e.g., acetone, N-methylpyrrolidone, N-ethylpyrrolidone, methyl isobutyl ketone, isophorone, cyclohexanone, methyl ethyl ketone, esters, e.g., methoxypropyl acetate, ethyl acetate and / or butyl acetate, amides, e.g., dimethylformamide and mixtures thereof.

[0131] Further optional components of coating composition (C) for use in ground coat compositions, mid coat compositions and clear coat compositions The ground coat, midcoat, and clearcoat compositions may optionally contain one or more components different from each of the components (A1), (A2), (T), (T*), (P), (B1), (B2), (B3), and (S).

[0132] Ground coat, mid coat, and clear coat compositions are used to form the multilayer coating of the present invention and may contain one or more commonly used additives depending on the desired application. For example, the coating composition may contain at least one additive selected from the group consisting of reactive diluents, e.g., polypropylene diol, light stabilizers, antioxidants, degassing agents, emulsifiers, slip additives, polymerization inhibitors, plasticizers, free radical polymerization initiators, adhesion promoters, flow regulators, film-forming aids, sagging control agents (SCAs), flame retardants, corrosion inhibitors, biocides, and / or matting agents. These can be used in known and conventional proportions. Preferably, their content is 0.01 to 25% by mass, more preferably 0.05 to 20% by mass, particularly preferably 0.1 to 15% by mass, most preferably 0.1 to 10% by mass, particularly preferably 0.1 to 7% by mass, and most preferably 0.1 to 5% by mass, based on the total mass of the coating composition according to the present invention.

[0133] Among the additives, the coating composition according to the present invention may optionally contain at least one thickener or rheological agent. Examples of such thickeners include inorganic thickeners, such as metal silicates such as layered silicates, and organic thickeners, such as poly(meth)acrylic acid thickeners and / or (meth)acrylic acid (meth)acrylate copolymer thickeners, polyurethane thickeners, and polymer waxes. Metal silicates are preferably selected from the group of smectites. Smectites are particularly preferably selected from the group of montmorillonite and hectorite. In particular, montmorillonite and hectorite are selected from the group consisting of aluminum-magnesium silicates and sodium-magnesium and sodium-magnesium fluorine-lithium phylrosilicates. These inorganic phylrosilicates are sold, for example, under the trademark Laponite®. Poly(meth)acrylic acid-based thickeners and (meth)acrylic acid (meth)acrylate copolymer thickeners are optionally crosslinked and / or neutralized with a suitable base. Examples of such thickeners include "alkaline swelling emulsions" (ASE) and their hydrophobically modified variant, "hydrophilic modified alkali swelling emulsions" (HASE). Preferably, these thickeners are anionic. Corresponding products, such as Rheovis® AS1130, are commercially available. Polyurethane-based thickeners (e.g., polyurethane-associative thickeners) are optionally crosslinked and / or neutralized with suitable bases. Corresponding products, such as Rheovis® PU1250, are commercially available. Examples of suitable polymer waxes are optionally modified polymer waxes based on ethylene-vinyl acetate copolymers. Corresponding products, for example, are commercially available under the name Aquatix® 8421.

[0134] If at least one thickening agent is present in the coating composition according to the present invention, it is preferably present in an amount of at most 7% by mass, more preferably at most 5% by mass, most preferably at most 3% by mass, particularly at most 2% by mass, and most preferably 1.5% by mass or less, based on the total mass of the coating material composition. The minimum amount of the thickening agent is preferably 0.1% by mass, based on the total mass of the coating composition, in each case.

[0135] The multilayer coatings provided in the present invention can also be described in terms of their color characteristics. Thus, the multilayer coatings of the present invention comprise at least one ground coat layer, at least one midcoat layer, and at least one clear coat layer, and typically, The following brightness L* values ​​are provided by CIELab. (i) With a field of view range of -15° to +45°, at least 80, (ii) If a metallic effect pigment is contained in the midcoat layer, at a viewing angle of +75° to +110°, at least 70, (iii) If the metallic effect pigment is not contained in the midcoat layer, at a viewing angle of +75° to +110°, at least 75, (iv) At least 105 at a field of view of +15°, It has, Granular G ≤2.5 diff , and Liquid metal index LMI ≥ 0.9 It has.

[0136] Preferably, the brightness (L*) value is ≥108 at a viewing angle of +15°, most preferably ≥110 or even ≥115, preferably, the brightness (L*) value is ≥78 at a viewing angle of +110°, most preferably ≥80 or even ≥85, preferably, granularity (G diff The ) value is ≤2.2, most preferably ≤2.0, or even ≤1.8, and preferably the liquid metal index (LMI) value is ≥0.95, more preferably ≥1.0, most preferably ≥1.20, and preferably not higher than 5.

[0137] Furthermore, it is preferable that the white multilayer coating has a slight bluish tint, that is, the b* value of the multilayer coating of the present invention is preferably ≤3, more preferably ≤1, most preferably ≤0, and even more preferably ≤-0.5 in the viewing angle range of -15° to 110°. In any case, the lower limit of b* is preferably -5 in the viewing angle range of -15° to 110°.

[0138] While the description of multilayer coatings based on color characteristics is valid in itself, the aforementioned color values ​​or ranges may be combined with the description of the multilayer coatings of the present invention by specific raw material components and their typical amounts, for example, plate-shaped titanium oxide pigment (P), non-plate-shaped pigments (T) and (T*), film-forming polymers (A1) and crosslinking agents (A2), dyes (B1), pigments (B2) and fillers (B3), solvents (S), and further components (C). From the above description of these raw material components and their amounts, multilayer coatings having respective color characteristics can be obtained. By explaining the effect of each color-related raw material component on the above parameters, those skilled in the art can obtain multilayer coatings defined by their color characteristics.

[0139] Method for preparing a multilayer coating and a multilayer coated substrate A further object of the present invention is a method for producing a multilayer coating, the method comprising the following steps: a. A step of applying at least one ground coat composition onto a coated or uncoated substrate to form one or more ground coat layers, wherein the ground coat composition comprises at least one non-plate-shaped titanium dioxide pigment (T). b. A step of forming one or more midcoat layers by applying at least one midcoat composition onto the sole or last groundcoat layer(s) thus formed, wherein the midcoat composition(s) comprises at least one plate-shaped titanium oxide pigment (P) selected from the group consisting of titanium hydrogen oxide (P1), titanium dioxide-coated fluorinated mica (P2), and titanium dioxide-coated aluminum (P3), and c. The step of applying at least one clear coat composition onto the sole or last midcoat layer(s) thus formed to form one or more clear coat layers(s), and d. A process of curing the ground coat layer, midcoat layer and / or clear coat layer, which may be uncured or not yet fully cured. Includes.

[0140] In relation to the multilayer coating compositions of the present invention and any preferred embodiments thereof described herein are also preferred embodiments of the methods of the present invention for producing coated or multilayer coated substrates.

[0141] The substrate is preferably a pre-coated substrate, especially if the substrate is a metal substrate. The metal substrate preferably has a primer and / or electrodeposition coating as a pre-coating layer and / or a conversion coating layer as a pre-treatment. If the substrate is a pre-coated or uncoated metal substrate, the metal is preferably steel, galvanized steel, aluminum, or an alloy thereof.

[0142] Ground coat, midcoat, and clearcoat coating compositions can be applied by a number of techniques well known in the art, including spray coating, drop coating, dip coating, roll coating, curtain coating, and other techniques. Preferably, the coating compositions of the present invention are applied by spray coating, more preferably by pneumatic or electrostatic spray coating. Wet-on-wet application is also possible, but not necessarily required.

[0143] The substrate used can be a plastic substrate, that is, a polymer substrate. Preferably, a thermoplastic polymer is used as such a substrate. Suitable polymers include poly(meth)acrylates, including polymethyl(meth)acrylate, polybutyl(meth)acrylate, polyethylene terephthalate, polybutylene terephthalate, polyvinylidene fluoride, polyvinyl chloride, polyesters, including polycarbonate and polyvinyl acetate, polyamides, polyolefins, such as polyethylene, polypropylene, polystyrene, and also polybutadiene, polyacrylonitrile, polyacetal, polyacrylonitrile-ethylene-propylene-diene-styrene copolymer (A-EPDM), ASA (acrylonitrile-styrene-acrylic ester copolymer) and ABS (acrylonitrile-butadiene-styrene copolymer), polyetherimide, phenolic resins, urea resins, melamine resins, alkyd resins, epoxy resins, polyurethanes, including TPU, polyetherketone, polyphenylene sulfide, polyether, polyvinyl alcohol, and mixtures thereof. Polycarbonate and poly(meth)acrylate are particularly preferred. The substrate may also be a composite substrate, such as a fiber-reinforced substrate containing polymer fibers like glass fibers, carbon fibers, or polyamide fibers. The substrate may also consist of multiple polymer layers.

[0144] Furthermore, the substrate used can be glass or fiber, particularly glass.

[0145] Coated or multi-layer coated substrates A further subject of the present invention is a multilayer coated substrate that can be obtained by one of the above methods for producing a multilayer coated substrate.

[0146] In relation to the coating compositions of the present invention, the methods of the present invention, and preferred embodiments thereof, any preferred embodiments described herein are also preferred embodiments of the coated or multilayer coated substrates of the present invention.

[0147] The coated substrate is preferably an automobile body and its components. [Examples]

[0148] In the following, unless otherwise specified, all quantities are in parts by mass, and all percentage values ​​are in mass percent.

[0149] Preparation of coating composition Preparation of midcourt composition and groundcourt composition The raw material components of midcoat compositions A and B (i.e., basecoat compositions for a three-layer coating) are shown in Tables 3 and 4.

[0150] The midcoat compositions A and B used in this invention are aqueous, one-component midcoat compositions, each containing one or a combination of the following plate-shaped titanium dioxide pigments: • Fluorinated mica effect pigments coated with flake-shaped titanium dioxide (CQV's Automotive Rutile Micro White A-901-F OPB and / or Automotive Rutile Fine White A-901-D-OPB) (according to the present invention), • Flake-shaped titanium hydrogen oxide (Ishihara's LPT-106) (according to the present invention), and • Aluminum pigment coated with flake-shaped titanium dioxide (according to the present invention), or • Non-fluorinated mica effect pigment coated with flake-shaped titanium dioxide (Ext. Mearlin Micro White 139M) (not according to the present invention).

[0151] Midcoat composition A further contains non-plate-shaped titanium dioxide pigment (Tacaya MT500 HD) used in the form of a pigment paste as described in Table 1.

[0152] Table 2 shows the raw material components of the ground coat composition.

[0153] The ground coat composition is an aqueous, one-component composition containing non-plate-shaped titanium dioxide pigments and another non-plate-shaped colorant, as shown in Table 2, both of which are incorporated into the ground coat composition in the form of pigment pastes as shown in Table 1.

[0154] The clear coat composition was a commercially available, conventional two-component solvent-based coating composition based on a crosslinked hydroxyl group-containing polymer having polyisocyanate.

[0155] Preparation of multilayer coatings (3-layer coatings) Ground coat compositions A and B were applied to a baked primer layer by air pressure coating to form ground coat layers with a dry layer thickness of approximately 33 μm (ground coat layer A from ground coat composition A) and approximately 17 μm (ground coat layer B from ground coat composition B).

[0156] Midcoat composition A was applied to groundcoat layer A using a wet-on-wet method with an ESTA bell after a 1-3 minute flash, and midcoat composition B was applied to groundcoat layer B using an air pressure application method after a 1-3 minute flash, forming midcoat layers A and B, respectively, with dry layer thicknesses of approximately 7 μm (midcoat layer A from midcoat composition A) and 10 μm (midcoat layer B from midcoat composition B).

[0157] Subsequently, after heating for 3-5 minutes (63°C), a two-component clear coat composition was applied using air pressure. The clear coat was a two-component polyurethane paint applied with a dry layer thickness of approximately 40-50 μm.

[0158] The coated panels were then flashed for 5-10 minutes and cured at 130°C for 25 minutes.

[0159] [Table 1]

[0160] [Table 2]

[0161] [Table 3]

[0162] [Table 4]

[0163] result Determination of L*, a*, b*, C*, and h values The color data for the three-layer coating was determined using a Byk Mac i instrument (Byk Gardner GmbH, Germany). D65 illumination (observer angle 10°) was used. Multi-angle (field of view: -15°, +15°, +25°, +45°, +75°, +110°) measurement geometry is shown in Figure 1. The 110° angle is also referred to as the "flop angle".

[0164] Using the aforementioned apparatus, the L*, a*, and b* values ​​for two-layer and three-layer coatings were determined. C* is calculated using the following formula: C* = (a 2 +b 2 ) 0.5 And h = arctan(b / a).

[0165] The CIELAB formula defines a color space characterized by the a* axis, which extends from green to red; the b* axis, which extends from blue to yellow; and the L* axis, which is perpendicular to the other two. Negative values ​​of b* indicate a bluish color, while positive values ​​of b* represent a more yellowish color. Higher L* (i.e., lightness) values ​​represent lighter colors, and lower L* values ​​represent darker colors.

[0166] Below, we show the color values ​​and the differences ΔL*, Δa*, and Δb* in the color space for a two-layer coating containing pastes A and B in the base coat layer, and a three-layer coating containing pastes A and B in the mid-coat layer, and in this case, another coloring pigment in the ground coat layer.

[0167] Flop exponent F i Calculation The flop exponent is calculated according to the following formula:

number

[0168] Bright area S a and brightness intensity Si decision The luster impression changes depending on the illumination angle. Therefore, the luster of the three-layer coating was measured using a BYK-mac i spectrophotometer by illuminating the sample with a very bright LED at three different angles: 15°, 45°, and 75°, and capturing images with a vertically positioned CCD camera (see Figure 2).

[0169] The images were analyzed using the image analysis algorithm of the BYK mac i spectrophotometer, and a histogram of brightness levels was used as the basis for calculating the luster parameter. To allow for clearer distinction, the luster impression was represented as a two-dimensional system: the luster area (S) at each angle. a ) and brightness intensity (S i ) was written there.

[0170] For simplification, the luminous area and intensity were combined into a single value, the luminous magnitude (SG).

[0171] Graininess G diff decision 3-layer coating graininess (G diff The granularity was evaluated by taking photographs with a CCD camera under diffuse illumination conditions using a white-coated hemisphere. The photographs were analyzed using a histogram of brightness levels, and the uniformity of the light and dark areas was summarized into a single granularity value calculated by a BYK mac i spectrophotometer.

[0172] A granularity value of zero indicates a solid color, while a higher value indicates that the sample appears granular or coarser under diffuse light.

[0173] Calculation of the Liquid Metal Index (LMI) The liquid metal index is calculated using the following formula: LMI=f i / g diff In the formula, the flop exponent F i and granular G diff This was calculated / determined as described above.

[0174] Determination of particle size distribution and Z-average particle size of non-platelet titanium dioxide pigments The aforementioned parameters were determined using dynamic light scattering with the Malvern Zetasizer (Malvern, S90 unit, Nanoseries Model ZEN 1690mfg 5 / 2017). To perform the measurements, the pigment dispersion was diluted with an appropriate solvent (deionized water for aqueous dispersions, and organic solvent for solvent-based dispersions) and the photon count rate was kept below approximately 300-500 counts when the unit was set to attenuator 7.

[0175] The procedure was as follows: Typically, when 0.07 g of paste containing 20% ​​by mass of pigment is first diluted in 15.0 g of deionized water, and then 5 drops of this solution are diluted again in 15.0 g of deionized water, the photon count rate is within the range described above. If the pigment paste contains more than 20% by mass of pigment or less than this value, the initial amount of 0.07 g should be increased or decreased as appropriate.

[0176] Using such a twice-diluted paste, volume-based D 10 , D 50 and D 90 The value was determined. D 10 This defines that 10% of the particles have a diameter smaller than this value. 50 This defines that 50% of the particles have a diameter smaller than this value, and is also known as the median diameter. 90 This defines that 90% of the particles have a diameter less than this value.

[0177] Determination of the lateral dimensions and distribution of plate-shaped pigments. After dispersing the samples in deionized water containing 0.04% Igepal CA630 surfactant, the transverse dimensions of the flake pigments (P1), (P2), and (P3) were measured by dynamic light scattering using a Mastersizer® 3000 Particle Size Analyzer (Malvern Instruments, Southborough, MA). The results were reported as volume-weighted average diameters D[4,3]. The diameters at which 10%, 50%, and 90% of the population were smaller were given by D 10 , D 50 and D 90 It is expressed as follows.

[0178] Determination of pigment plate thickness The plate thickness can be determined as follows: First, flake-shaped pigments are dispersed in a suitable solvent and incorporated into a midcoat composition. Next, the midcoat composition containing plate-shaped pigments is sprayed onto a substrate and cured. The resulting film is peeled from the edge of the sample, and small pieces of the film are cut using a diamond knife and a microtome, and the thin sections are transferred onto a TEM grid. The thin sections are observed using STEM or TEM to determine the thickness of each flake pigment.

[0179] Determination of the dry layer thickness of the coating layer The dry layer thickness of the coating layer of the present invention was determined using an elcometer such as the Fischer Dualscope FMP20C.

[0180] 3-layer coating (Ground coat A - Mid coat A - Clear coat) Tables 5-1, 5-2, and 5-3 compare three further three-coat layer coatings. The first (C A1) uses a mid-coat layer containing natural mica coated with conventional fine-particle titanium dioxide and chromium(III) oxide; the second (E A2) replaces the titanium dioxide-coated mica with titanium oxide-containing plates; and the third (E A3) replaces the titanium dioxide-coated natural mica in (C A1) with ultrafine synthetic-based titanium dioxide-coated mica (fluorophlogopite) (see Table 3).

[0181] [Table 5]

[0182] Near the off-specular range (angles -15° to +15°), the brightness of E A2 is significantly increased. Furthermore, the difference between angles -15° and +15° is greater for the natural mica-containing midcoat coated with titanium dioxide and chromium(III) oxide, exhibiting more metallic behavior. At the far off-specular angle of +110°, the b* value decreases significantly (becoming bluer) with synthetic mica coated with titanium dioxide, and especially with the addition of titanium oxide, thus exhibiting a bluer hue and, consequently, a purer white appearance. The overall texture does not increase significantly compared to the control material, with a granularity of <1.7 (G diff The value still maintained a silky appearance (see Tables 5-2 and 5-3).

[0183] [Table 6]

[0184] [Table 7]

[0185] In particular, the difference in color values ​​(△) between △L* and △b* showed a favorable color as a result of introducing titanium dioxide-coated synthetic mica or titanium oxide sheets into the midcoat.

[0186] 3-layer coating (Ground coat B - Mid coat B - Clear coat) Tables 6-1 and 6-2 compare two three-coat layer coatings. The first (C B1) uses a midcoat layer without titanium dioxide-coated aluminum, while the second (E B2) has titanium dioxide-coated aluminum added. C B1 is equivalent to E B2, but still belongs to the present invention, merely demonstrating a further improvement of the coating composition by adding a small amount of titanium dioxide-coated aluminum flakes. Both midcoat compositions A further contain titanium oxide (Ishihara's LPT-106) and titanium dioxide-coated mica effect pigment (Automotive Rutile Micro White A-901-F OPB) (see Table 4).

[0187] [Table 8]

[0188] Near the off-specular range (-15° to +15°), the brightness of E B2 is significantly increased. Furthermore, the difference between angles -15° and +15° is greater with the aluminum-containing midcoat, exhibiting more metallic behavior. In the far off-specular range (angles +75° and +110°), the addition of titanium dioxide-coated aluminum reduces the b* value (making it bluer), thus resulting in a bluer hue and, consequently, a purer white appearance.

[0189] [Table 9]

[0190] In particular, the difference in color values ​​(△) between △L* and △b* showed a favorable color as a result of introducing titanium dioxide-coated aluminum into the midcoat.

[0191] [Table 10]

Claims

1. The following ingredients, a) At least one ground coat layer comprising at least one non-plate-shaped titanium dioxide pigment (T), b) Below, i. At least one small plate-shaped titanium oxide pigment (P) selected from the group consisting of titanium hydrogen oxide (P1), fluorinated mica coated with titanium dioxide (P2), and aluminum coated with titanium dioxide (P3). Including at least one midcourt layer on top of the at least one groundcourt layer, c) At least one clear coat layer on the at least one midcoat layer Includes the following lightness L* values ​​according to CIELab. (i) In the field of view range of -15° to +45°, at least 80, (ii) When a metallic effect pigment is contained in the midcoat layer, at least 70 in the viewing angle range of +75° to +110°, (iii) If the metallic effect pigment is not contained in the midcoat layer, at least 75 in the viewing angle range of +75° to +110° It has, and Granularity ≤ 2.5 (G ｄｉｆｆ ) has, The CIELab system is characterized by having a field of view of -15°, +15°, +25°, +45°, +75°, and +110°, and a b* value of -5 to +4. Multilayer coating.

2. b) At least one midcourt layer, ii) At least one non-platelet titanium dioxide pigment (T) The multilayer coating according to claim 1, further comprising:

3. b) At least one midcourt layer, i. At least two small plate-shaped titanium oxide pigments (P) selected from the group consisting of titanium hydrogen oxide (P1), fluorinated mica coated with titanium dioxide (P2), and aluminum coated with titanium dioxide (P3). A multilayer coating according to claim 1 or 2, characterized by including the following:

4. b) At least one midcourt layer, a. Fluorinated mica coated with at least one plate-shaped titanium oxide hydrogen and at least one plate-shaped titanium dioxide, or b. At least one plate-shaped titanium oxide (P) selected from the group consisting of at least one non-plate-shaped titanium dioxide pigment (T*) and fluorinated mica coated with titanium hydrogen oxide and titanium dioxide. A multilayer coating according to claim 1 or 2, characterized by including the following:

5. The multilayer coating according to claim 1 or 2, characterized in that (b) at least one midcoat layer comprises aluminum coated with at least one plate-shaped titanium dioxide.

6. The hydrogen titanate is represented by one of the following formulas, H ２ Ti ３ O ７ and H ４ｘ／３ Ti ２－ｘ／３ O ４ ． nH ２ O, where x is 0.50 to 1.0 and n is 0 to 2, and / or the fluorinated mica is fluorophlogopite, The multilayer coating according to claim 1 or 2, characterized in that.

7. The multilayer coating according to claim 1 or 2, characterized in that, at viewing angles of -15°, +15°, +25°, +45°, +75°, and +110°, a* is -3.8 to +3.8 and b* is -5 to +4 according to the CIELab system.

8. It comprises at least one ground court layer, at least one midcourt layer, and at least one clearcourt layer, and The following brightness L* values ​​are provided by CIELab. (i) In the field of view range of -15° to +45°, at least 80, (ii) When a metallic effect pigment is contained in the midcoat layer, at least 70 in the viewing angle range of +75° to +110°, (iii) If the metallic effect pigment is not contained in the midcoat layer, at least 75, and in the viewing angle range of +75° to +110° (iv) At least 105 at a field of view of +15° It has, Granular G ≤ 2.5 ｄｉｆｆ , and Liquid metal index (LMI) ≥ 0.9 [LMI is given by the formula: LMI = Fi / G ｄｉｆｆ (In the formula, Fi represents the flop exponent, G ｄｉｆｆ [This is calculated as the granularity of the three-layer coating.] It has, At field angles of -15°, +15°, +25°, +45°, +75°, and +110°, the b* value from the CIELab system is between -5 and +4. The ground coat layer comprises at least one non-plate-shaped titanium dioxide pigment (T), The midcoat layer comprises at least one plate-shaped titanium oxide pigment (P) selected from the group consisting of titanium hydrogen oxide (P1), fluorinated mica coated with titanium dioxide (P2), and aluminum coated with titanium dioxide (P3). Characterized by Multilayer coating.

9. The multilayer coating according to claim 8, characterized in that the ground coat layer, midcoat layer and clear coat layer are further defined by claim 1 or 2.

10. A method for manufacturing a multilayer coating as defined in claim 1 or 2, comprising the following steps: a. A step of applying at least one ground coat composition onto a coated or uncoated substrate to form one or more ground coat layers, wherein the ground coat composition comprises at least one non-plate-shaped titanium dioxide pigment (T). b. A step of forming one or more midcoat layers by applying at least one midcoat composition onto the sole or last groundcoat layer(s) thus formed, wherein the midcoat composition(s) comprises at least one plate-shaped titanium oxide pigment (P) selected from the group consisting of titanium hydrogen oxide (P1), titanium dioxide-coated fluorinated mica (P2), and titanium dioxide-coated aluminum (P3), and c. A step of applying at least one clear coat composition onto the single or last midcoat layer(s) thus formed to form one or more clear coat layers(s), and d. A process of curing the ground coat layer, midcoat layer, and / or clear coat layer, which may be uncured or not yet fully cured. Methods that include...

11. A method for producing a multilayer coating according to claim 10, characterized in that the midcoat composition comprises a film-forming polymer (A1), and, if the film-forming polymer (A1) is externally crosslinkable, a crosslinking agent (A2), and If present, the total mass ratio of titanium hydrogen oxide (P1) to film-forming polymer (A1) and crosslinking agent (A2) is in the range of 0.01 to 0.5, and / or If present, the mass ratio of fluorinated mica (P2) coated with plate-shaped titanium dioxide to the total mass of film-forming polymer (A1) and crosslinking agent (A2) is in the range of 0.01 to 0.5, and / or A method wherein, if present, the total mass ratio of titanium dioxide-coated aluminum pigment (P3) to film-forming polymer (A1) and crosslinking agent (A2) is in the range of 0.001 to 0.

2.

12. A multilayer coated substrate characterized by comprising the multilayer coating described in claim 1 or 2, wherein the substrate is an uncoated or pre-coated substrate selected from the group consisting of a metal substrate, a plastic substrate, glass, or fiber.

13. The multilayer coated substrate according to claim 12, which is a pre-coated metal substrate comprising at least one of a primer coating layer, an electrodeposition coating layer, and a conversion coating layer.

14. A multilayer coated substrate according to claim 12, which is an automobile body or a part thereof.

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