milky white

Abstract

The present disclosure relates to multilayer coatings applied to substrates such as automotive vehicle substrates and methods of making and applying such coatings.

Description

Technical Field

[0001] This disclosure relates to multilayer coatings applied to substrates such as motor vehicle substrates, and methods for preparing and applying such coatings. Background Technology

[0002] Multilayer coatings are applied to a wide variety of substrates to provide color and other visual effects, corrosion resistance, abrasion resistance, chemical resistance, and more. For example, multilayer coatings typically include a base coat that provides color or other special visual effects, and a clear coat that provides abrasion and scratch resistance. For multilayer coatings applied to substrates such as those used in motor vehicles, a primer layer and a second primer coat are also typically included.

[0003] Typical special effects coatings provide a shimmering effect, where the reflectivity of the metallic color changes as the coating is rotated within the viewing angle. In the CIELAB color space (L*a*b*), the luminance L* value varies with the viewing angle and is expressed as the shimmer index.

[0004] However, the expectation is to provide a coating with a new color impression. Summary of the Invention

[0005] The above problem can be solved by a multilayer coating comprising: (a) a substrate, (b) a base coat applied to at least a portion of the substrate, wherein the dry film thickness of the base coat is in the range of 5 to 35 μm, and wherein the base coat comprises an angle-dependent color pigment, and (c) a transparent coating applied to at least a portion of the base coat, wherein, based on the total weight of the transparent coating, the transparent coating comprises 0.01 wt.% to 1.50 wt.% titanium dioxide having a volume average particle size Dv50 in the range of 1 to 250 nm, and the dry film thickness of the transparent coating is in the range of 15 to 80 μm.

[0006] A method for preparing a multilayer coating, particularly a multilayer coating according to the present disclosure, is provided, comprising, in sequence: (A) forming a base coat on at least a portion of a substrate by depositing a base coat composition on at least a portion of a substrate, wherein the base coat composition comprises an angle-dependent color pigment; (B) optionally drying and / or curing the base coat; (C) forming a transparent coating on at least a portion of the base coat by depositing a transparent coating composition on at least a portion of the substrate, wherein the transparent coating composition comprises 0.01 wt.% to 1.50 wt.% titanium dioxide having a volume average particle size Dv50 in the range of 1 to 250 nm, based on the total solids content of the transparent coating composition; and (D) drying and / or curing the transparent coating or both the base coat and the transparent coating, wherein the dry film thickness of the transparent coating is in the range of 15 to 80 μm, and the dry film thickness of the base coat is in the range of 5 to 35 μm.

[0007] Furthermore, this disclosure relates to the use of a transparent coating composition to form a transparent coating on a base layer, the transparent coating composition comprising 0.01 wt.% to 1.50 wt.% titanium dioxide, based on the total solids content of the transparent coating composition, the titanium dioxide having a volume average particle size Dv50 in the range of 1 to 250 nm, wherein the base layer has a color flutter index of at least 1.

[0008] In addition, a laminate is provided comprising a protective film, particularly a removable protective film, (i) a transparent coating applied to at least a portion of the protective film, wherein the transparent coating comprises 0.01 wt.% to 1.50 wt.% titanium dioxide having a volume average particle size Dv50 in the range of 1 to 250 nm based on the total weight of the transparent coating, and the dry film thickness of the transparent coating is in the range of 15 to 80 μm, (ii) an optional undercoat applied to at least a portion of the transparent coating, wherein, in particular, the dry film thickness of the undercoat is in the range of 5 to 35 μm, and wherein the undercoat particularly comprises an angle-dependent color pigment, (iii) an optional carrier film applied to at least a portion of the undercoat, (iv) an optional adhesive layer applied to at least a portion of the transparent coating, the undercoat and / or the carrier film, and (v) an optional liner applied to at least a portion of the adhesive layer.

[0009] In addition, a method for applying a laminate to a substrate is provided, comprising (I) providing a laminate according to the present disclosure, (II) contacting the substrate with the laminate, wherein the substrate particularly comprises an undercoat applied to at least a portion of the substrate, wherein the dry film thickness of the undercoat is in the range of 5 to 35 μm, and wherein the undercoat comprises an angle-dependent color pigment, and (III) optionally applying an adhesive to the substrate prior to contacting the substrate with the laminate, thereby applying the laminate to the adhesive.

[0010] Surprisingly, the multilayer coatings according to this disclosure exhibit a large color range, particularly a large δb* shift. Furthermore, a milky white effect is achieved without negatively impacting the color of the multilayer coatings, such as the base coat. Attached Figure Description

[0011] Figure 1 : This illustrates a multilayer coating according to the present disclosure.

[0012] Figure 2a : This illustrates another multilayer coating according to this disclosure.

[0013] Figure 2b This illustrates a method of applying a laminate to a coated substrate.

[0014] Figure 3 The image shows a laminate according to this disclosure. Detailed Implementation

[0015] It should be understood that this disclosure may assume various alternative variations and sequences of steps, unless otherwise expressly stated.

[0016] It should be understood that any range of numbers described herein is intended to include all subranges contained therein. For example, the range “1 to 10” is intended to include all subranges between (and including) the minimum value 1 and the maximum value 10, i.e., a minimum value greater than or equal to 1 and a maximum value less than or equal to 10.

[0017] In this application, unless otherwise specifically stated, the use of "or" means "and / or," even if "and / or" may be explicitly used in certain circumstances. Furthermore, in this application, unless otherwise specifically stated, the use of "a / an" means "at least one / a type." For example, "a" multilayer coating, "a" base coating, "a" clear coating, etc., refer to one or more of any of these items. For example, the statement "a" angle-dependent color pigment includes a plural, i.e., multiple angle-dependent color pigments. Additionally, for example, the statement "angle-dependent color pigment" means that one type of angle-dependent color pigment may exist or multiple different types of angle-dependent color pigments may exist.

[0018] As used herein, the term "aqueous" refers to a carrier or solvent in which the solvent comprises water and up to 50 wt.% of a water-miscible organic solvent (such as an alkyl ether).

[0019] As used herein, the term "base coat" refers to a coating that provides protection, color, concealment (also known as "opacity"), or visual appearance. The term "base coat coating composition" refers to a coating composition containing pigments and / or colorants that can be used to form a base coat.

[0020] The term "transparent coating" refers to a coating that is substantially transparent rather than opaque. However, a transparent coating may contain pigments and / or colorants, but should only contain amounts of pigments and / or colorants that will not render the coating opaque.

[0021] As used herein, the term "coating" (and "coat") refers to a finished product resulting from applying a coating composition to a substrate and forming a coating, such as by curing. Both primer and clear coat can be coatings, and any of these coatings can be formed according to the methods of this disclosure.

[0022] This disclosure relates to a multilayer coating comprising: (a) a substrate; (b) a base coat applied to at least a portion of the substrate, wherein the dry film thickness of the base coat is in the range of 5 to 35 μm, and wherein the base coat comprises an angle-dependent color pigment; and (c) a transparent coating applied to at least a portion of the base coat, wherein, based on the total weight of the transparent coating, the transparent coating comprises 0.01 wt.% to 1.50 wt.% titanium dioxide having a volume average particle size Dv50 in the range of 1 to 250 nm, and the dry film thickness of the transparent coating is in the range of 15 to 80 μm.

[0023] The base coat can have a chromatic aberration index of at least 1. Therefore, the chromatic aberration of the base coat can be achieved by including an angle-dependent pigment in the base coat.

[0024] The indications in this disclosure based on the weight percentage of the corresponding coating, such as a clear coating or a base coat, can also be considered as the solids content of the coating composition used to obtain the corresponding coating.

[0025] In the context of multilayer coatings, the base coat (b) and clear coat refer to the cured coating.

[0026] Angle-dependent color pigments are used in applications such as automotive coatings, decorative coatings, plastic coloring, printing inks (especially safety inks), textiles, and cosmetics. Their optical effects are produced by the directional reflection of light from primarily plate-like particles, which are typically metallic or have a structured refractive index contrast, with a length scale comparable to the wavelength of light. Depending on the nature of the pigment particles, the pigments are called metallic effect pigments (e.g., aluminum, zinc, copper, or alloys thereof) or interference pigments (e.g., mica based on titanium dioxide coating, such as muscovite, phlogopite, and biotite).

[0027] Because incident light is directionally reflected by primarily sheet-like particles, color effect pigments, such as those oriented in coatings, exhibit angle-dependent colorimetry; that is, the color they perceive (brightness and / or hue and / or chromaticity) varies with the angle of illumination or observation.

[0028] Interference pigments can comprise monolayers or multilayer structures. Perceived color is influenced by interference in, for example, one or more thin layers, and optionally also by absorption by chromophores (organic or inorganic compounds that absorb wavelengths of light in the visible and / or ultraviolet range) or color centers. Color centers are electron-hole pairs generated by lattice defects in crystalline solid materials that absorb wavelengths in the visible and / or ultraviolet range. Interference with or without absorption results in a variety of hue variations, depending on the thickness of one or more thin layers and the effective refractive index of those layers.

[0029] Suitable angle-dependent color pigments are flake pigments, such as aluminum flake pigments, zinc flake pigments, copper flake pigments, or alloys thereof. Ideally, the angle-dependent color pigment contains aluminum flake pigments or flake pigments containing aluminum. Therefore, (b) the undercoat layer can contain flake pigments (as angle-dependent color pigments). Flake pigments typically include flake pigments coated with one of the aforementioned metals (such as metal oxides).

[0030] The thickness of flake pigments can range from 10 to 1000 μm, such as 10 to 80 μm, 20 to 80 μm, or 100 to 1000 μm. The volume average particle size (Dv50) can range from 5 to 50 μm, such as 5 to 35 μm, 8 to 32 μm, or 12 to 30 μm. The Dv50 and thickness of flake pigments can be obtained from the technical documents of the flake pigment manufacturer.

[0031] Dv50 can be determined by laser diffraction. Dv50 can be determined using the Microtrac MT3300EXII laser diffraction measuring device manufactured by MicrotracBEL Corp., specifically according to the user manual. Dv50 can also be determined by dynamic light scattering. Dv50 can be determined using the HORIBA SZ-100V2 nanoPartica dynamic light scattering (DLS) measuring device, specifically according to the user manual. Dynamic light scattering is particularly useful for low particle sizes (e.g., 0.3 nm to 10 µm), while laser diffraction is particularly useful for particle sizes from 10 nm to up to 5 mm. For example, ASTM E3247-20 specifies the use of dynamic light scattering for Dv50. Generally, the intensity can be converted into volumetric or number distribution.

[0032] Commercially available aluminum flake pigments, such as STAPA® HYDROLAN 2154 and HYDROLAN 8154, are sold by Eckart.

[0033] In addition, angle-dependent color pigments may be used in accordance with the disclosure of US 6,894,086 B2, which is incorporated by reference.

[0034] The optical properties (such as color flutter index, L*, a*, b*) of coatings (particularly multilayer coating stacks or base coats according to this disclosure) can be measured using a multi-angle spectrophotometer BYK-mac i (manufactured by BYK), and in particular, following the instructions in the instrument manual. The BYK-mac i performs color measurements at 5 angles for light / dark path evaluation: 15° / 25° / 45° / 75° / 110°. Color calculations and measurements can be found in DIN EN ISO 11664 (2020-03) standard (1-4).

[0035] A chromatic aberration index of 0 indicates a pure color, while metallic or pearlescent base / clear paint colors with very high chromatic aberration may have an index of 15-17. The chromatic aberration index can be calculated as follows:

[0036]

[0037] The base coat is expected to have a color flutter index of at least 1, such as at least 2, at least 3, at least 4, or at least 5. The base coat may have a color flutter index of 1 to 20, such as 2 to 18, 3 to 15, 4 to 12, or 5 to 10.

[0038] The multilayer coatings according to this disclosure are expected to have a color flutter index of at least 0.1, such as at least 0.5, at least 1, at least 1.5, or at least 2. The multilayer coatings may have a color flutter index of 0.1 to 15, such as 0.5 to 10, 0.8 to 8, 1 to 7, or 1.5 to 6.

[0039] It is expected that the color index of the multilayer coating according to this disclosure is lower than that of the base coat.

[0040] Angle-dependent color pigments are generally considered to be pigments that exhibit a color index of at least 1 in a coating. For example, the color index can be measured using a primer mentioned in the example, where the pigment to be measured is the only pigment in the primer in the desired amount, and a clear coating is applied over the primer which contains no pigment.

[0041] Typically, the base coat is formed from a base coat paint composition. Typically, the clear coat is formed from a clear coat paint composition.

[0042] The dry film thickness (or dry film thickness) of the primer coating can be in the range of 7 to 28 μm, such as 8 to 26 μm, 9 to 25 μm or 10 to 20 μm.

[0043] The dry film thickness (or dry film thickness) of the transparent coating can be in the range of 20 to 70 μm, such as 30 to 65 μm, 35 to 60 μm, or 45 to 57 μm. A dry film thickness of 20 to 30 μm is particularly desirable, such as 35 to 45 μm, 44 to 48 μm, 49 to 52 μm, or 53 to 56 μm.

[0044] The dry film coating thickness of multilayer coatings can be in the range of 70 to 200 μm, such as 80 to 160 μm, 90 to 150 μm or 100 to 130 μm.

[0045] Coating thickness can be measured using the magnetic induction method with a non-destructive coating thickness measuring device, the "LAYERCHECK 750 USB" (ERICHSEN GmbH & Co. KG, Germany). Film thickness determination typically follows DIN EN ISO 2808.

[0046] Based on the total weight of the primer, the primer may have a total pigment content of at least 10 wt.%, such as at least 15 wt.%, at least 20 wt.%, or at least 25 wt.%. For example, based on the total weight of the primer, the primer may have a total pigment content of 10 wt.% to 30 wt.%, such as 15 wt.% to 30 wt.%, 20 wt.% to 30 wt.%, or 25 wt.% to 30 wt.%.

[0047] Based on the total solids content of the primer composition, the primer composition may have a total pigment content of at least 10 wt.%, such as at least 15 wt.%, at least 20 wt.%, or at least 25 wt.%. For example, based on the total solids content of the primer composition, the primer composition may have a total pigment content of 10 wt.% to 30 wt.%, such as 15 wt.% to 30 wt.%, 20 wt.% to 30 wt.%, or 25 wt.% to 30 wt.%.

[0048] The primer may contain additional pigments. Additional pigments relative to the primer refer to pigments that are different from angle-dependent pigments. These additional pigments may include colorants or mixtures of colorants. Colorants can be used to provide the desired color for multiple layers of coating.

[0049] As used herein, the term "colorant" means any substance that imparts color and / or other opacity and / or other visual effects to a composition. Colorants can be added in any suitable form, such as discrete particles, dispersions, solutions, and / or flakes.

[0050] Other pigments in the primer may include carbazole dioxazine pigments, azo pigments, monoazo pigments, diazo pigments, naphthol AS pigments, salt-type (lake) pigments, benzimidazolone pigments, metal complex pigments, isoindolineone pigments, isoindoline pigments, polycyclic phthalocyanine pigments, quinacridone pigments, perylene pigments, perylene ketone pigments, diketopyrrolopyrrole pigments, indigo pigments, anthraquinone pigments, indanone pigments, anthraquinone pigments, flavanone pigments, pinantrone pigments, anthraquinone pigments, dioxazine pigments, triarylcarbium pigments, quinoline ketone pigments, diketopyrrolopyrrole red (“DPPBO Red”), titanium dioxide, carbon black, and mixtures thereof.

[0051] Other pigments in the primer may include violet mica, blue mica, green mica, copper mica, alizarin red (PR83), lampblack (PBk 7), chrome iron brown (PBr29), alizarin red (PR83), perylene violet (PV29), yellow iron oxide (PY42), nickel azo yellow (PY150), bismuth vanadate orange (PO86), iron oxide red (PR101), phthalocyanine blue (PB15), phthalocyanine blue RS (PB15:1), phthalocyanine blue (PB15:2), phthalocyanine blue BGS (PB15:3), phthalocyanine blue NCF (PB15:4), phthalocyanine blue (PB15:5), phthalocyanine blue (PB15:6), cobalt blue (PB28), tanninone blue (PB60), phthalocyanine green BS (PG7), phthalocyanine green YS (PG36), cobalt titanate green (PG50), carbon black (PBk6), and particles larger than 250 μm. Titanium dioxide (PW6), iron oxide red (PR101:1), transparent iron oxide red (PR101t), iron oxide yellow (PY42t), transparent iron oxide yellow (PY42t), mica, glass flakes, and / or combinations thereof. These pigments can be found in the Art Pigment Color Database: Pigment Orange, PO (artiscreation.com, David G. Myers).

[0052] However, angle-dependent pigments may be the only pigment present in the base coat. In other words, there may be no other pigments present in the base coat.

[0053] Based on the total weight of the clear coating, the clear coating has a total pigment content of up to 3 wt.%, such as up to 2 wt.%, up to 1.5 wt.%, up to 1 wt.%, up to 0.9 wt.%, up to 0.8 wt.%, up to 0.7 wt.%, or up to 0.6 wt.%. For example, based on the total weight of the clear coating, the clear coating has a total pigment content of 0.1 wt.% to 3 wt.%, such as at least 0.5 wt.% to 2 wt.%, at least 0.6 wt.% to 1.5 wt.%, or at least 0.7 wt.% to 1 wt.%.

[0054] Based on the total solids content of the transparent coating composition, the transparent coating composition can have a total pigment content of up to 3 wt.%, such as up to 2 wt.%, up to 1.5 wt.%, up to 1 wt.%, up to 0.9 wt.%, up to 0.8 wt.%, up to 0.7 wt.%, or up to 0.6 wt.%. For example, based on the total solids content of the transparent coating composition, the transparent coating composition has a total pigment content of 0.1 wt.% to 3 wt.%, such as 0.5 wt.% to 2 wt.%, 0.6 wt.% to 1.5 wt.%, or 0.7 wt.% to 1 wt.%.

[0055] The transparent coating may contain titanium dioxide having a volume average particle size Dv50 in the range of 12 to 80 nm, such as 20 to 70 nm, 30 to 60 nm or 35 to 55 nm.

[0056] The transparent coating may contain titanium dioxide with a particle size in the range of 12 to 80 nm, such as 20 to 70 nm, 30 to 60 nm or 35 to 55 nm.

[0057] Therefore, based on the total weight of the transparent coating, the transparent coating may contain 0.01 wt.% to 1.50 wt.% of titanium dioxide, the titanium dioxide having an average particle size Dv50 in the range of 1 to 250 nm, wherein the transparent coating contains titanium dioxide having a volume average particle size Dv50 in the range of 12 to 80 nm, such as 20 to 70 nm, 30 to 60 nm or 35 to 55 nm.

[0058] In addition, based on the total weight of the transparent coating, the transparent coating may contain 0.01 wt.% to 1.50 wt.% of titanium dioxide having a volume average particle size Dv50 in the range of 12 to 80 nm, such as 20 to 70 nm, 30 to 60 nm or 35 to 55 nm.

[0059] Dv50 can be determined by laser diffraction. Dv50 can be measured using the Microtrac MT3300EXII laser diffraction measuring device manufactured by MicrotracBEL Corp., specifically according to the user manual. Dv50 can also be determined by dynamic light scattering. Dv50 can be measured using the HORIBA SZ-100V2 nanoPartica dynamic light scattering (DLS) measuring device, specifically according to the user manual. Dynamic light scattering is particularly suitable for low particle sizes, such as 0.3 nm to 10 µm, while laser diffraction is particularly suitable for particle sizes from 10 nm to up to 5 mm. For example, ASTM E3247-20 specifies the use of dynamic light scattering for Dv50. Generally, the intensity can be converted into volumetric or number distribution.

[0060] Therefore, Dv50 can be determined by laser diffraction and / or by dynamic light scattering.

[0061] A suitable titanium dioxide for use in transparent coatings is commercially available titanium dioxide MT-700HD from TAYCA Ltd. MT-700HD has a volume average particle size Dv50 of 50 nm.

[0062] Based on the total weight of the transparent coating, the transparent coating may contain 0.04 wt.% to 1.30 wt.% of titanium dioxide having a volume average particle size Dv50 in the range of 1 to 250 nm, such as 0.09 wt.% to 1.10 wt.%, 0.14 wt.% to 1.00 wt.%, 0.20 wt.% to 0.90 wt.%, 0.25 wt.% to 0.80 wt.%, 0.35 wt.% to 0.70 wt.%, 0.40 wt.% to 0.70 wt.%, 0.50 wt.% to 0.70 wt.%, or 0.50 wt.% to 0.60 wt.%.

[0063] Therefore, based on the total weight of the transparent coating, the transparent coating may contain 0.01 wt.% to 1.50 wt.% titanium dioxide having a volume average particle size Dv50 in the range of 1 to 250 nm, such as 0.04 wt.% to 1.30 wt.%, 0.09 wt.% to 1.10 wt.%, 0.14 wt.% to 1.00 wt.%, 0.20 wt.% to 0.90 wt.%, 0.25 wt.% to 0.80 wt.%, 0.35 wt.% to 0.70 wt.%, 0.40 wt.% to 0.70 wt.%, 0.50 wt.% to 0.70 wt.%, or 0.50 wt.% to 0.60 wt.%, wherein the transparent coating contains a particle size Dv50 having a volume average particle size Dv50 in the range of 12 to 80 nm, such as 20 to 70 nm. Titanium dioxide with a volume average particle size Dv50 in the range of nm, 30 to 60 nm or 35 to 55 nm.

[0064] Furthermore, based on the total weight of the transparent coating, the transparent coating may contain 0.01 wt.% to 1.50 wt.%, such as 0.04 wt.% to 1.30 wt.%, 0.09 wt.% to 1.10 wt.%, 0.14 wt.% to 1.00 wt.%, 0.20 wt.% to 0.90 wt.%, 0.25 wt.% to 0.80 wt.%, 0.35 wt.% to 0.70 wt.%, 0.40 wt.% to 0.70 wt.%, 0.50 wt.% to 0.70 wt.%, or 0.50 wt.% to 0.60 wt.%, of titanium dioxide having a volume average particle size Dv50 in the range of 12 to 80 nm, such as 20 to 70 nm, 30 to 60 nm, or 35 to 55 nm.

[0065] The pigment weight concentration (PWC) of the clear coating can be from 0.01% to 2%, such as 0.05% to 1.8%, 0.1% to 1.3%, 0.2% to 1.1%, 0.25% to 1%, 0.40% to 0.90%, or 0.50% to 0.80%. Alternatively, the pigment weight concentration of the clear coating can be from 0.15% to 0.30%, such as 0.2% to 0.6%, 0.3% to 0.5%, 0.5% to 0.6%, 0.6% to 0.7%, 0.8% to 0.9%, or 1.2% to 1.4%. The pigment weight concentration is the total pigment content divided by the sum of the total pigment content and the binder content. The binder includes all film-forming resins and all crosslinking agents. Crosslinking agents are, for example, polyisocyanates.

[0066] Pigment weight concentration (PWC) can be calculated as follows:

[0067]

[0068] The pigments in the coating composition refer to the total weight of pigments, and the binder refers to the total weight of binders in the coating composition. The binder includes all film-forming resins and all crosslinking agents. Crosslinking agents, for example, are polyisocyanates.

[0069] The ratio of total pigment weight to total base weight can be 0.0001 to 0.1, such as 0.0005 to 0.08, 0.0009 to 0.04, 0.001 to 0.03, 0.002 to 0.02, 0.003 to 0.01, 0.004 to 0.009, or 0.005 to 0.008.

[0070] The ratio of total pigment weight to total base weight can be as follows:

[0071]

[0072] The pigments in the coating composition refer to the total weight of pigments, and the binder refers to the total weight of binders in the coating composition. The binder includes all film-forming resins and all crosslinking agents. Crosslinking agents, for example, are polyisocyanates.

[0073] The BET surface area of ​​titanium dioxide in a transparent coating (i.e., titanium dioxide with a volume average particle size Dv50 in the range of 1 to 250 nm) can be 20 to 80 m². 2 / g, such as 25 to 70 m 2 / g, 25 to 50 m 2 / g or 30 to 45 m 2 / g. BET surface area can be measured according to Brunauer-Emmert-Teller theory / DIN ISO 9277:2003-05.

[0074] Titanium dioxide in transparent coatings (i.e., titanium dioxide with a volume average particle size Dv50 in the range of 1 to 250 nm) can have a rutile structure.

[0075] The oil absorption (g / 100g pigment) of titanium dioxide (i.e., titanium dioxide with a volume average particle size Dv50 in the range of 1 to 250 nm) in transparent coatings can be 15 to 50, such as 20 to 45, 25 to 45, or 30 to 40. The oil absorption can be measured according to DIN ISO 787-10.

[0076] Transparent coatings (c) may contain additional pigments such as violet mica, blue mica, green mica, copper mica, crimson (PR83), lampblack (PBk 7), chrome iron brown (PBr29), crimson (PR83), perylene violet (PV29), iron oxide yellow (PY42), azo nickel yellow (PY150), bismuth vanadate orange (PO86), iron oxide red (PR101), phthalocyanine blue (PB15), phthalocyanine blue RS (PB15:1), phthalocyanine blue (PB15:2), phthalocyanine blue BGS (PB15:3), phthalocyanine blue NCF (PB15:4), phthalocyanine blue (PB15:5), phthalocyanine blue (PB15:6), cobalt blue (PB28), tanninone blue (PB60), phthalocyanine green BS (PG7), phthalocyanine green YS (PG36), cobalt titanate green (PG50), carbon black (PBk6), and particle sizes exceeding 250. Titanium dioxide (PW6), iron oxide red (PR101:1), transparent iron oxide red (PR101t), iron oxide yellow (PY42t), transparent iron oxide yellow (PY42t), mica, glass flakes, and / or combinations thereof are used in transparent coatings. "Other pigments relative to transparent coatings" refers to pigments that differ from titanium dioxide having a volume average particle size Dv50 in the range of 1 to 250 nm.

[0077] Based on the total weight of the clear coating, additional pigments may be present in the clear coating (c) in amounts ranging from 0.1 wt.% to 1.5 wt.%, such as 0.2 wt.% to 1.1 wt.%, 0.3 wt.% to 0.9 wt.%, or 0.4 wt.% to 0.7 wt.%.

[0078] However, titanium dioxide with a volume average particle size Dv50 in the range of 1 to 250 nm is expected to be the only pigment present in transparent coatings. In other words, no other pigments are required in transparent coatings.

[0079] Ideally, a transparent paint is a transparent paint. To determine the transparency of a paint, the corresponding paint composition can be applied in a wedge shape onto a black-and-white chart and allowed to dry or harden. A black-and-white chart is typically used when determining the black / white opacity of a paint composition. If the black-and-white chart below is visible at the desired paint thickness, the paint is transparent. Black / white opacity can be determined by the user, for example, with their eyes.

[0080] The multilayer coating may also include an electrodeposited coating applied to at least a portion of the substrate, wherein the electrodeposited coating is positioned between the primer and the substrate.

[0081] The multilayer coating may also include a primer or a second primer applied to at least a portion of the substrate, wherein the primer or the second primer is positioned between the primer (b) and the substrate, or the primer or the second primer is positioned between the primer (b) and the electrodeposited coating.

[0082] The substrate can be any suitable substrate. The corresponding coating compositions (or laminates) described herein can be applied to a variety of substrates known in the coating industry. For example, the substrate, particularly a portion of the substrate surface, may contain at least one material selected from metals, plastics, ceramics (such as boron carbide or silicon carbide), glass, wood, paper, cardboard, rubber, leather, textiles, glass fiber composites, carbon fiber composites, existing coatings, or mixtures thereof.

[0083] Metals may include, but are not limited to, ferrous metals, tin steel, aluminum, aluminum alloys, zinc-aluminum alloys, titanium, titanium alloys, magnesium, magnesium alloys, copper, copper alloys, and mixtures thereof. Ferrous metals may include iron, steel, and their alloys. Non-limiting examples of useful steel materials may include rolled steel, galvanized (zinc-coated) steel, electro-galvanized steel, stainless steel, acid-etched steel, zinc-iron alloys, and combinations thereof. Combinations or composites of ferrous and nonferrous metals may also be used. Aluminum alloys of the 1XXX, 2XXX, 3XXX, 4XXX, 5XXX, 6XXX, 7XXX, or 8XXX series, and clad and cast aluminum alloys of the A356, 1XX.X, 2XX.X, 3XX.X, 4XX.X, 5XX.X, 6XX.X, 7XX.X, or 8XX.X series may also be used as base materials. Magnesium alloys of the AZ31B, AZ91C, AM60B, or EV31A series may also be used as base materials. The substrate can be pretreated with a pretreatment solution, including zinc phosphate pretreatment solutions, such as those described in US 4,793,897 and US 5,588,989, or zirconium-containing pretreatment solutions, such as those described in US 7,749,368 and US 8,673,091.

[0084] The substrate can be a vehicle, storage tank, windmill, packaging substrate, wood flooring and furniture, clothing, electronic products, glass and transparent film, sports equipment, buildings, bridges, etc. According to this disclosure, the substrate can be a vehicle component.

[0085] The term "vehicle" is used in its broadest sense and includes (but is not limited to) all types of aircraft, spacecraft, watercraft, and land vehicles. For example, vehicles can include aircraft such as airplanes, including private planes, as well as small, medium, or large commercial passenger planes, cargo planes, and military aircraft; helicopters, including private, commercial, and military helicopters; and aerospace vehicles, including rockets and other spacecraft. Vehicles can include land vehicles such as trailers, cars, trucks, buses, long-distance buses, freight cars, ambulances, fire trucks, RVs, travel trailers, mini-cars, carriages, forklifts, sit-on lawnmowers, agricultural vehicles (e.g., tractors and harvesters), construction vehicles (e.g., excavators, bulldozers, and cranes), golf carts, motorcycles, bicycles, trains, and trams. Vehicles also include watercraft such as, for example, ships, submarines, small boats, jet skis, and hovercraft.

[0086] Coated vehicle components may include bodywork components (e.g., but not limited to doors, body panels, trunk lids, roof panels, hoods, roofs and / or stringers, rivets, wheels, landing gear assemblies and / or shells used on aircraft), hulls, marine superstructures, vehicle frames, chassis, and vehicle components that are not normally visible during use, such as engine components, motorcycle fairings and fuel tanks, fuel tank surfaces, and other vehicle surfaces exposed to or potentially exposed to fuel, aerospace solvents, and aerospace hydraulic fluids. Any vehicle component that can benefit from a coating as defined herein, whether exposed or hidden from view during normal use, may undergo coating.

[0087] The multilayer coating according to this disclosure can have a color range ΔC* of at least 2, such as at least 5, at least 8, at least 10, at least 20, or at least 30. The color range can be calculated using the following formula.

[0088] .

[0089] Color path ΔC* can be measured using a multi-angle spectrophotometer BYK-mac i (manufactured by BYK), specifically in accordance with DIN EN ISO 11664 (2020-03) standard (1-4).

[0090] The multilayer coatings according to this disclosure can have a Δb* of 4.5 to 50, such as 5 to 40, 6 to 40, or 10 to 35, between angles of 75° and 15°. Δb* can be measured using a multi-angle spectrophotometer BYK-mac i (manufactured by BYK), specifically following DIN EN ISO 11664 (2020-03) standard (1-4). The color shift Δb* can be calculated as follows:

[0091] .

[0092] The multilayer coatings according to this disclosure can have a Δa* of 0.5 to 15, such as 0.8 to 10, 1 to 8, or 1.5 to 5, between angles of 75° and 15°. Δa* can be measured using a multi-angle spectrophotometer BYK-mac i (manufactured by BYK), specifically following DIN EN ISO 11664 (2020-03) standard (1-4). The color shift Δa* can be calculated as follows:

[0093] .

[0094] A method for preparing a multilayer coating, particularly a multilayer coating according to the present disclosure, is provided, comprising, in sequence: (A) forming a base coat on at least a portion of a substrate by depositing a base coat composition onto at least a portion of a substrate, wherein the base coat composition comprises an angle-dependent color pigment; (B) optionally drying and / or curing the base coat; (C) forming a transparent coating on at least a portion of the base coat by depositing a transparent coating composition onto at least a portion of the substrate, wherein the transparent coating composition comprises 0.01 wt.% to 1.50 wt.% of titanium dioxide having a volume average particle size Dv50 in the range of 1 to 250 nm, based on the total solids content of the transparent coating composition; and (D) drying and / or curing either the transparent coating or both the base coat and the transparent coating, wherein the dry film thickness of the transparent coating is in the range of 15 to 80 μm, and the dry film thickness of the base coat is in the range of 5 to 35 μm.

[0095] Primer compositions typically also include a film-forming resin and a crosslinking agent suitable for crosslinking the film-forming resin. Therefore, a primer composition includes a film-forming resin, a crosslinking agent suitable for crosslinking the film-forming resin, and an angle-dependent color pigment.

[0096] Transparent coating compositions typically comprise a film-forming resin, a crosslinking agent suitable for crosslinking the film-forming resin, and 0.01 wt.% to 1.50 wt.% titanium dioxide based on the total solids content of the transparent coating composition, the titanium dioxide having a volume average particle size Dv50 in the range of 1 to 250 nm.

[0097] The coating composition can be applied to at least a portion of the substrate surface by any standard method in the art, such as electrophoretic coating, spraying, electrostatic spraying, dip coating, roller coating, brush coating, etc.

[0098] As used herein, the term "film-forming resin" refers to a resin that, upon removal of any diluent or carrier present in the composition or upon curing under ambient conditions (e.g., at temperatures in the range of 20°C to 25°C) or at elevated temperatures (e.g., at temperatures in the range of 40°C to 200°C), can form a self-supporting continuous film on at least a horizontal surface of a substrate. The terms "resin" and "of resin," etc., are used interchangeably with the terms "polymer" and "polymerized," etc. Further, as used herein, the term "polymer" refers to its common meaning in the art, a macromolecular compound, i.e., a compound with a relatively high molecular weight (e.g., 500 Da or higher) whose structure comprises multiple repeating units (also referred to as "monomers") that are actually or conceptually derived from chemical nuclides with relatively low molecular weights. Unless otherwise stated, molecular weight is based on average weight ("M"). w The polystyrene standard was determined by gel permeation chromatography.

[0099] Environmental conditions refer to the curing of the composition without the aid of heat (e.g., not baking in an oven, not using forced air, etc.).

[0100] Examples of film-forming resins include acrylic resins, vinyl resins, polyester resins, polysiloxane resins, epoxy resins, polyurethane resins, polyamide resins, copolymers thereof, and mixtures thereof.

[0101] Acrylic resins can be homopolymers or copolymers, obtained by polymerizing one or more monomers, including substituted or unsubstituted (meth)acrylic acid and (meth)acrylates. Hereinafter, the terms “(meth)acrylic acid” and “(meth)acrylate”, and similar terms, refer to acrylic acid or acrylates and their corresponding methacrylic acid or methacrylates, respectively. Suitable (meth)acrylates may include, but are not limited to, alkyl (meth)acrylates, cycloalkyl (meth)acrylates, alkylcycloalkyl (meth)acrylates, aralkyl (meth)acrylates, alkylaryl (meth)acrylates, aryl (meth)acrylates, and (meth)acrylates containing functional groups. As used herein, the term “functional group” refers to a group containing one or more hydrogen-free and sp... 3Groups consisting of atoms other than carbon atoms. Examples of functional groups include, but are not limited to, hydroxyl, carboxylic acid, amide, isocyanate, urethane, thiol, amino, sulfone, sulfoxide, phosphine, phosphite, phosphate, and halide groups. Non-limiting examples of acrylic resins may include acrylic resins derived from: methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, isobutyl methacrylate, 2-ethylhexyl methacrylate, isooctyl methacrylate, isobornyl methacrylate, isodecanyl methacrylate, lauryl methacrylate, tridecyl methacrylate, tetradecyl methacrylate, hexadecyl methacrylate, octadecyl methacrylate, stearyl methacrylate, benzyl methacrylate, 2-phenoxyethyl methacrylate, 3,3,5-trimethylcyclohexyl methacrylate, 3-methylphenyl methacrylate, 1-naphthyl methacrylate, 3-phenyl-n-propyl methacrylate, 2-phenyl-aminoethyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, 4-hydroxybutyl methacrylate, glycidyl methacrylate, or combinations thereof. According to this disclosure, acrylic resins can have hydroxyl values ​​ranging from 20 to 400, such as 30 to 350, or 40 to 300, or 50 to 250. The hydroxyl value can be determined according to DIN EN ISO 4629-1:2016. Suitable acrylic resins include, but are not limited to, acrylic resins commercially available from Allnex Germany GmbH under the trademark SETALUX®, including but not limited to SETALUX® 1776 VS-65, SETALUX® 1774 SS-70, SETALUX® 1797 SS-70, SETALUX® 1762 W-70, SETALUX® 1760 VB-64, SETALUX® 1795 VX-74, and SETALUX® DA870 BA; and acrylic resins commercially available from Allnex Germany GmbH under the trademark VIACRYL®, such as VIACRYL SC 370 / 75SNA.

[0102] Vinyl resins can be homopolymers or copolymers, obtained by polymerizing one or more monomers containing vinyl aromatic compounds, such as styrene and vinyltoluene; nitrile compounds, such as (meth)acrylonitrile; vinyl and vinylidene halide compounds, such as vinyl chloride and vinylidene fluoride; and vinyl esters, such as vinyl acetate. Suitable vinyl resins may be those available under the trademark LUMIFLON from AGC Chemicals Europe, Ltd. (Netherlands). TMVinyl resin.

[0103] Polyester resins can be prepared in known ways, for example, by polymerization of polyamines and polyacids or by ring-opening polymerization of lactams. As used herein, the term "polyol" refers to a compound having one or more hydroxyl groups per molecule, for example, containing 2, 3, 4, 5, 6 or more hydroxyl groups per molecule; and the term "polyacid" refers to a compound having one or more carboxylic acid groups per molecule, for example, containing 2, 3, 4, 5, 6 or more carboxylic acid groups per molecule, and containing an anhydride of the corresponding acid. Suitable polyols include, but are not limited to, alkylene glycols, such as ethylene glycol, propylene glycol, butanediol, 1,6-hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, polyethylene glycol having a molecular weight in the range of 200 to 10,000 g / mol, polypropylene glycol having a molecular weight in the range of 200 to 10,000 g / mol, and polypropylene glycol having a molecular weight in the range of 300 to 10,000 g / mol. Polybutanediol and neopentyl glycol with molecular weights within the specified range; bisphenol A; hydrogenated bisphenol A; bisphenol F; hydrogenated bisphenol F; cyclohexanediol; propylene glycols such as 1,2-propanediol, 1,3-propanediol, butyl ethyl propylene glycol, 2-methyl-1,3-propanediol, and 2-ethyl-2-butyl-1,3-propanediol; butanediols such as 1,4-butanediol, 1,3-butanediol, 2,3-butanediol, 1,2-butanediol, 3-methyl-1,2-butanediol, and 2-ethyl-1,4-butanediol; 1,2-Pentanediol, 1,5-Pentanediol, 1,4-Pentanediol, 3-methyl-4,5-Pentanediol, 2,2,4-trimethyl-1,3-Pentanediol and other pentanediols; 1,6-hexanediol, 1,5-hexanediol, 1,4-hexanediol, 2,5-hexanediol and other hexanediols; poly(caprolactone) glycols having molecular weights in the range of 400 to 10,000 g / mol; polyether glycols, such as poly(oxytetramethylene) glycol; trimethylolpropane; pentaerythritol; dipentaerythritol; trimethylolethane; trimethylolbutane; dimethylolcyclohexane and glycerol. Suitable polycarboxylic acids may include, but are not limited to, maleic acid; fumaric acid; itaconic acid; adipic acid; azelaic acid; succinic acid; sebacic acid; glutaric acid; phthalic acid; isophthalic acid; 5-tert-butylisophthalic acid; tetrachlorophthalic acid; trimellitic acid; naphthalenedicarboxylic acid; naphthalenetetracarboxylic acid; terephthalic acid; hexahydrophthalic acid; methylhexahydrophthalic acid; dimethyl terephthalate; cyclohexanedicarboxylic acid; 1,3-cyclohexanedicarboxylic acid; 1,4-cyclohexanedicarboxylic acid; tricyclodecane polycarboxylic acid; methylenetetrahydrophthalic acid; ethylenehexahydrophthalic acid; cyclohexanetetracarboxylic acid; cyclobutanetetracarboxylic acid; and anhydrides of all the above polycarboxylic acids. Suitable lactones may include, but are not limited to, propiolactone; γ-butyrolactone; δ-valerolactone; ε-caprolactone; α-angelicolactone; and mixtures thereof.Suitable polyester resins include, but are not limited to, polyester resins bearing the trademark SETAL®, such as SETAL® 1715 VX-74, SETAL® 91703SS-53 and SETAL® 91715 SS-55, which are commercially available from Allnex Germany GmbH (Germany).

[0104] Polysiloxane resins may include, but are not limited to, alkyl-substituted polysiloxanes, aryl polysiloxanes, copolymers, blends, and mixtures thereof. The alkyl substituent may be a short-chain alkyl group having 1 to 4 carbon atoms, such as methyl or propyl. The aryl substituent may include a phenyl group. Suitable polysiloxane resins include, but are not limited to, Silres® 601 or Silres® M 50 E, both commercially available from Wacker Chemie AG (Germany), and DOWSIL, commercially available from Dow Chemical Company (USA). TM RSN-6018.

[0105] Epoxy resins can be prepared by known methods, for example, by reacting a compound containing at least one epoxy functional group with a cyclic co-reactant containing at least two hydroxyl groups. Examples of suitable compounds containing one epoxy functional group include, but are not limited to: glycidyl ether; epichlorohydrin; glycidyl amine and mixtures thereof. As used herein, the terms “epoxy” and “epoxide” are used interchangeably. Examples of suitable cyclic co-reactants containing at least two hydroxyl groups include, but are not limited to, bisphenol A; hydrated bisphenol A; bisphenol F; hydrated bisphenol F; phenolic varnish resins, such as phenolic varnishes, cresol phenolic varnishes; and mixtures thereof. Suitable epoxy resins include, but are not limited to, Eponex 1510, Eponex 1513, Epikote Resin 862 and Epikote Resin 828, which are commercially available from Hexion (USA); Epodil 757, which is commercially available from Evonik Corporation (Germany); and Araldite GY 2600, Araldite GY 281 and Araldite EPN 1138, which are commercially available from Huntsman (USA).

[0106] Polyurethane resins can be prepared by known methods, such as by reacting polyisocyanates with polyols. As used herein, the term "polyisocyanate" refers to a compound having more than one isocyanate group per molecule, for example, having 2, 3, 4, 5, 6 or more isocyanate groups per molecule. Suitable polyisocyanates include aliphatic polyisocyanates, such as 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, and 1,6-hexamethylene diisocyanate; alicyclic polyisocyanates, such as isophorone diisocyanate and 4,4'-methylene-bis(cyclohexyl) isocyanate; and aromatic polyisocyanates such as 4,4'-diphenylmethane diisocyanate, toluene diisocyanate, 1,2,4-phenyltriisocyanate, tetramethylphenyl dimethylene diisocyanate, and polymethylene polyphenyl isocyanate. Non-limiting examples of suitable polyols may be the polyols described above for the preparation of polyester resins. Suitable polyurethane resins include, but are not limited to, the reaction products of Desmodur N 3300 (commercially available from Covestro (Germany)) and alkylene glycols (such as ethylene glycol or propylene glycol).

[0107] Suitable polyamide resins can be prepared in known ways, such as by polymerization of polyamines and polyacids or by ring-opening polymerization of lactams. In this document, the term "polyamine" refers to a compound having more than one amino group per molecule, for example, having 2, 3, 4, 5, 6 or more amino groups per molecule. Suitable polyamines include, but are not limited to, aliphatic diamines, such as 1,2-ethylenediamine, 1,2-propanediamine, 1,3-propanediamine, 1,2-butanediamine, 1,3-butanediamine, 1,4-butanediamine, 1,3-pentanediamine, 1,5-pentanediamine, 1,6-hexanediamine, etc. 2-Methyl-1,5-pentanediamine, 2,5-dimethylhexane-2,5-diamine, 2,2,4-trimethyl-1,6-hexanediamine, 2,4,4-trimethyl-1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, and 1,10-decanediamine; alicyclic diamines such as 2,4'-diaminodicyclohexylmethane, 4,4'-diaminodicyclohexylmethane, 3,3'- -Dimethyl-4,4'-diaminodicyclohexylmethane, 3,3'-diethyl-4,4'-diaminodicyclohexylmethane, etc.; aromatic diamines such as 1,2-phenylenediamine, 1,3-phenylenediamine, 1,4-phenylenediamine, 1,5-naphthylenediamine, 1,8-naphthylenediamine, 2,4-toluenediamine, 2,5-toluenediamine, 2,6-toluenediamine, 3,3'-dimethyl-4,4'-biphenylenediamine, etc. Non-limiting examples of suitable polyacids may include those listed above for the preparation of polyesters. Suitable lactams may include, but are not limited to, β-propiolactam; γ-butyrolactam; δ-valerolactam; ε-caprolactam; and mixtures thereof. Suitable polyamide resins include, but are not limited to, those commercially available from Lawter (USA) under the trademark Flex-Rez.TM such as Flex-Rez TM 0080CS, Flex-Rez TM 1060CS, Flex-Rez TM 1074CS A polyamide resin.

[0108] Specifically, the film-forming resin may include acrylic polyols, acrylic polyesters, or combinations thereof.

[0109] Based on the total weight of solids in the corresponding coating composition (i.e., primer composition or clear coat composition), the film-forming resin may be present in an amount of at least 25 wt.%, such as at least 30 wt.%, such as at least 40 wt.%, such as at least 50 wt.%. Based on the total weight of solids in the corresponding coating composition (i.e., primer composition or clear coat composition), the film-forming resin may be present in an amount of not more than 95 wt.%, such as not more than 90 wt.%, such as not more than 85 wt.%, such as not more than 80 wt.%. Based on the total weight of solids in the corresponding coating composition (i.e., primer composition or clear coat composition), the range of film-forming resins may include, for example, 25 to 95 wt.%, such as 25 to 90 wt.%, such as 25 to 85 wt.%, such as 25 to 80 wt.%, such as 30 to 95 wt.%, such as 30 to 90 wt.%, such as 30 to 85 wt.%, such as 30 to 80 wt.%, such as 40 to 95 wt.%, such as 40 to 90 wt.%, such as 40 to 85 wt.%, such as 40 to 80 wt.%, such as 50 to 95 wt.%, such as 50 to 90 wt.%, such as 50 to 85 wt.%. Based on the total weight of solids in the corresponding coating composition (i.e., primer composition or clear coat composition), the film-forming resin may be present in the coating composition in any of the above values, such as 25 to 95 wt.%, 30 to 90 wt.%, 35 to 85 wt.%, 40 to 80 wt.%, or 50 to 80 wt.%.

[0110] The coating compositions disclosed herein may also include a crosslinking agent suitable for crosslinking the film-forming resin. As used herein, the term "crosslinking" refers to the formation of covalent bonds between polymer chains that make up the polymer molecules. The terms "crosslinking agent," "curing agent," and "crosslinker" are used interchangeably herein. Curing or crosslinking reactions can be initiated, for example, by exposing the coating composition to heat or radiation, but can also be carried out under ambient conditions to form a cured coating. The crosslinking agent may include at least one of polyepoxides, polyisocyanates, and amino resins. The crosslinking agent may include an amino resin. The crosslinking agent typically includes a melamine resin.

[0111] Suitable polyepoxides may include, but are not limited to, low molecular weight polyepoxides (e.g., polyepoxides having a molecular weight in the range of 200 to 500 g / mol) and higher molecular weight polyepoxides (e.g., polyepoxides having a molecular weight in the range of 500 to 10,000 g / mol). Suitable low molecular weight polyepoxides include, but are not limited to, 3,4-epoxycyclohexylmethyl, 3,4-epoxycyclohexanecarboxylic acid ester and bis(3,4-epoxy-6-methylcyclohexyl-methyl) adipic acid ester, bisphenol A diglycidyl ether, bisphenol E diglycidyl ether and bisphenol F diglycidyl ether. Suitable higher molecular weight polyepoxides may include, but are not limited to, polyglycidyl ethers of cyclic polyols, such as polyglycidyl ethers of polyphenols (e.g., bisphenol A, bisphenol F, resorcinol, hydroquinone, benzyl alcohol, phloroglucinol, and catechol); or polyglycidyl ethers of polyols, such as aliphatic polyols, particularly alicyclic polyols, such as 1,2-cyclohexanediol, 1,4-cyclohexanediol, 2,2-bis(4-hydroxycyclohexyl)propane, 1,1-bis(4-hydroxycyclohexyl)ethane, 2-methyl-1,1-bis(4-hydroxycyclohexyl)propane, 2,2-bis(4-hydroxy-3-tert-butylcyclohexyl)propane, 1,3-bis(hydroxymethyl)cyclohexane, and 1,2-bis(hydroxymethyl)cyclohexane. Examples of aliphatic polyols may include, but are not limited to, trimethylpentanediol and neopentanediol. Suitable polyepoxides include, but are not limited to, EPONEX, which is commercially available from Hexion Inc. (USA). TM 1510, Epon® 828, EPIKOTE TM Resin 828.

[0112] Suitable polyisocyanates can be aliphatic, aromatic, or mixtures thereof. As used herein, the term "polyisocyanate" is intended to include both blocked and unblocked polyisocyanates. As used herein, the term "blocked polyisocyanate" refers to an adduct derived from an equilibrium reaction of an isocyanate with a blocking agent, wherein the adduct is thermally unstable and dissociates (deblocks) at elevated temperatures (such as above 120°C). The term "unblocked isocyanate" refers to a polyisocyanate without a blocking agent. Polyisocyanates can be prepared from a variety of isocyanate-containing materials. Examples of suitable polyisocyanates include (but are not limited to) trimers prepared from: toluene diisocyanate, 4,4'-methylene-bis(cyclohexyl)isocyanate, isophorone diisocyanate, isomeric mixtures of 2,2,4- and 2,4,4-trimethylhexamethylene diisocyanate, 1,6-hexamethylene diisocyanate, tetramethylphenyl diisocyanate, and 4,4'-diphenylmethylene diisocyanate. The isocyanate groups of the polyisocyanate may be blocked or unblocked as needed. Examples of suitable blocking agents include materials that deblock at elevated temperatures, such as above 120°C, such as lower aliphatic alcohols having 1 to 6 carbon atoms, including methanol, ethanol, and n-butanol; alicyclic alcohols such as cyclohexanol; aromatic alkyl alcohols such as phenylmethanol and methylphenylmethanol; and phenolic compounds such as phenol itself and substituted phenols in which the substituents do not affect the coating operation, such as cresol and nitrophenol. Diol ethers may also be used as blocking agents. Suitable glycol ethers include ethylene glycol butyl ether, diethylene glycol butyl ether, ethylene glycol methyl ether, and propylene glycol methyl ether. Other suitable blocking agents include oximes such as methyl ethyl ketone oxime, acetone oxime, and cyclohexanone oxime; lactams such as ε-caprolactam; pyrazoles such as dimethylpyrazole; and amines such as dibutylamine. Suitable polyisocyanates include, but are not limited to, Desmodur ultra grade polyisocyanates, such as Desmodur ultra DN, Desmodur ultra N 3300, Desmodur ultra IL EA, and Desmodur UltraN 3300 BA / SN, which are commercially available from Covestro (Germany).

[0113] Suitable amino resins can be obtained by the condensation reaction of an aldehyde (such as formaldehyde) with a compound containing at least two amine or amide groups per molecule. Suitable examples of aldehydes include, but are not limited to, formaldehyde, acetaldehyde, crotonaldehyde, and benzaldehyde. Suitable examples of compounds containing at least two amine or amide groups include, but are not limited to, melamine, urea, and phenylmelamine. Suitably, amino resins can generally be etherified with an alcohol (such as methanol, ethanol, butanol, or mixtures thereof). Suitable amino resins include, but are not limited to, Maprenal® amino resins, such as Maprenal MF 612 / 70B, Maprenal MF 613 / 71B and Maprenal MF 650 / 55IB, which are commercially available from Prefere Resin Holding GmbH (Germany); Cymel® amino crosslinking agents, such as Cymel 303, Cymel 202, Cymel 1161, Cymel 325 and Cymel 1133, which are commercially available from Allnex Industries (Germany); and Setamine® amino resins, such as Setamine US-138 BB-70 and Setamine US-146 BB-72, which are commercially available from Allnex (Germany).

[0114] Based on the total weight of solids in the corresponding coating composition (i.e., primer composition or clear coat composition), the crosslinking agent may be present in an amount not exceeding 5 wt.%, such as at least 10 wt.%, such as at least 15 wt.%, such as at least 20 wt.%. Based on the total weight of solids in the corresponding coating composition (i.e., primer composition or clear coat composition), the crosslinking agent may be present in an amount not exceeding 75 wt.%, such as not exceeding 70 wt.%, such as not exceeding 60 wt.%, such as not exceeding 50 wt.%. Based on the total weight of solids in the corresponding coating composition (i.e., primer composition or clear coat composition), the range of crosslinking agents may include, for example, 5 to 75 wt.%, such as 5 to 70 wt.%, such as 5 to 60 wt.%, such as 5 to 50 wt.%, such as 10 to 75 wt.%, such as 10 to 70 wt.%, such as 10 to 60 wt.%, such as 10 to 50 wt.%, such as 15 to 75 wt.%, such as 15 to 70 wt.%, such as 15 to 60 wt.%, such as 15 to 50 wt.%, such as 20 to 75 wt.%, such as 20 to 70 wt.%, such as 20 to 60 wt.%, such as 20 to 50 wt.%. Based on the total weight of solids in the corresponding coating composition (i.e., primer composition or clear coat composition), the presence of crosslinking agent in the coating composition can be within any of the above values, such as 5 to 75 wt.%, 10 to 70 wt.%, 15 to 60 wt.%, or 20 to 50 wt.%.

[0115] The corresponding coating compositions (i.e., primer compositions or clear coating compositions) may also contain solvents or solvent mixtures. Suitable solvents include water, organic solvents, and mixtures thereof. Organic solvents may include any suitable organic solvents known in the art. Non-limiting examples of suitable organic solvents may include, but are not limited to, alcohols, glycol ethers, esters, ether esters and ketones, aliphatic and / or aromatic hydrocarbons, such as, for example, methanol, ethanol, isopropanol, n-butanol, 2-butanol, tridecanol, methyl isobutyl ketone, methyl ethyl ketone, 3-butoxy-2-propanol, ethyl 3-ethoxypropionate, butyl glycol, butyl glycol acetate, butanol, dipropylene glycol methyl ether, diethylene glycol monobutyl ether, butyl glycolate, hexane, heptane, octane, toluene, xylene, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, isobutyl acetate, 2-butoxyethyl acetate, pentyl acetate, isoamyl acetate, n-butyl acetate, diethylene glycol butyl ether acetate, acetone, xylene, toluene, etc. Based on the total weight of the corresponding coating composition (i.e., primer composition or clear coat composition), the solvent may be present in the coating composition in an amount of 5-70 wt.%, such as 10-65 wt.%, such as 15-60 wt.%, such as 20-55 wt.%, such as 30-50 wt.%.

[0116] The corresponding coating composition (i.e., primer composition or clear coating composition) can be a water-based coating composition or a solvent-based coating composition.

[0117] The corresponding coating composition (i.e., primer composition or clear coat composition) can be a solvent-based coating composition. As used herein, the term "solvent-based coating composition" refers to a coating composition comprising a solvent mixture containing an organic solvent and less than 50 wt.%, such as less than 40 wt.%, less than 30 wt.%, less than 20 wt.%, less than 10 wt.%, less than 5 wt.%, less than 2 wt.%, or less than 1 wt.% of water based on the total weight of the solvent mixture. A solvent-based coating composition may be anhydrous, i.e., containing less than 0.5 wt.%, such as less than 0.2 wt.%, or less than 0.1 wt.% of water based on the total weight of the solvent mixture. A solvent-based coating composition may be completely anhydrous, i.e., containing 0 wt.% of water based on the total weight of the solvent mixture.

[0118] Furthermore, the corresponding coating composition (i.e., primer composition or clear coat composition) can be a water-based coating composition. The term "water-based coating composition" refers to a coating composition comprising a solvent mixture containing water and less than 50 wt.% organic solvent based on the total weight of the solvent mixture, such as less than 40 wt.%, less than 30 wt.%, less than 20 wt.%, less than 10 wt.%, less than 5 wt.%, less than 2 wt.%, or less than 1 wt.%. Water-based coating compositions may be solvent-free, i.e., they may contain less than 0.5 wt.% organic solvent, such as less than 0.2 wt.% or less than 0.1 wt.%. Water-based coating compositions may be completely water-free, i.e., they may contain 0 wt.% organic solvent based on the total weight of the solvent mixture.

[0119] The corresponding coating compositions (i.e., primer compositions or clear coat compositions) may also contain at least one additional component selected from colorants such as pigments, dyes, and dyes; plasticizers; antioxidants; hindered amine light stabilizers; UV absorbers and stabilizers; surfactants; flow control agents; fillers; reactive diluents; catalysts; abrasive carriers, such as acrylic abrasive carriers; defoamers; dispersants; adhesion promoters; antistatic agents; and mixtures thereof. When used, based on the total solid weight of the corresponding coating composition (i.e., primer compositions or clear coat compositions), the coating composition may contain a total of 0.1 to 45 wt.%, such as 1 to 40 wt.%, or 1.5 to 35 wt.%.

[0120] Suitable dyes include, but are not limited to, acid dyes, azo dyes, basic dyes, direct dyes, disperse dyes, reactive dyes, solvent dyes, sulfur dyes, and mordant dyes, such as bismuth vanadate, anthraquinone, perylene, aluminum, quinacridone, thiazole, thiazide, azo, indigo derivatives, nitro, nitroso, oxazine, phthalocyanine, quinoline, symmetrical diphenylethylene, and triphenylmethane.

[0121] Suitable plasticizers include, but are not limited to, phthalates such as dibutyl phthalate, butyl benzyl phthalate, diisooctyl phthalate and decyl butyl phthalate; chlorinated paraffins; and hydrogenated terphenyl.

[0122] Suitable examples of antioxidants used, for example, to prevent resin oxidation due to heat exposure during production and application, or to prevent paint yellowing, include, but are not limited to, phenolic antioxidants, phosphite antioxidants, etc. Suitable antioxidants include, but are not limited to, Irganox® antioxidants commercially available from BASF SE (Germany), such as Irganox 245, Irganox 1010, and Irganox 1076.

[0123] As used herein, “hindered amine light stabilizers” (“HALS”) refer to compounds containing amine functional groups that are added to polymeric materials to inhibit or delay their degradation by, for example, photo-oxidation. Typically, tetramethylpiperidine derivatives are used. Examples of suitable hindered amine light stabilizers (HALS) include, but are not limited to, Tinuvin® light stabilizers available from BASF (Germany), such as TINUVIN® 292, TINUVIN® 123, TINUVIN® 328, TINUVIN® 622, TINUVIN® 783, and TINUVIN® 770. As used herein, “UV absorbers and stabilizers” refer to compounds used to absorb UV radiation to reduce UV degradation of polymeric materials. Examples of suitable UV absorbers and stabilizers include, but are not limited to, CYASORB light stabilizers available from Solvay (Germany), such as CYASORB UV-1164L; and TINUVIN® 1130 available from BASF (Germany).

[0124] Surfactants can be added to the appropriate coating compositions (i.e., primer compositions or clear coat compositions) to facilitate, for example, the flow and wetting of the substrate. Suitable surfactants include, but are not limited to, alkyl sulfates (e.g., sodium dodecyl sulfate); ether sulfates; phosphate esters; sulfonates; and their various alkali, ammonium, and amine salts; fatty alcohol ethoxylates; alkylphenol ethoxylates (e.g., nonylphenol polyether); salts and / or combinations thereof.

[0125] As used herein, the term "flow control agent" refers to a compound that controls the rheological behavior of a coating composition during application, drying, and / or curing, including controlling viscosity, thixotropic properties under shear stress, and leveling properties when applied to a substrate surface. Flow control agents may include sagging control agents. As used herein, the term "sagging control agent" refers to a compound that minimizes sagging (i.e., defects such as teardrops caused by gravity-driven flow of a wet coating composition) when applied to a substrate, particularly a substrate containing a non-horizontal (e.g., vertical) surface. Suitable flow control agents, especially sagging control agents, may include, but are not limited to, the compounds described in US 4,311,622 A, EP 0 192 304 A1, and EP 3 728 482 A1.

[0126] As used herein, a “reactive diluent” refers to a monomer or oligomer that reduces the viscosity of a coating composition (i.e., a primer composition or a clear coat composition) and can copolymerize during the curing of the coating composition. Suitable reactive diluents may have a molecular weight in the range of 100 to 350 g / mol. Suitable examples of reactive diluents include, but are not limited to, epoxy-functionalized compounds, vinyl-functionalized compounds, (meth)acrylate compounds, and combinations thereof.

[0127] The corresponding coating compositions (i.e., primer compositions or clear coating compositions) may contain a catalyst to facilitate any desired curing reaction. Any curing catalyst commonly used for catalyzing crosslinking reactions may be used, and there are no particular limitations on the catalyst. Non-limiting examples of catalysts include phenyl acid phosphates, sulfonic acid functional catalysts such as dodecylbenzenesulfonic acid (DDBSA), dinonylnaphthalenesulfonic acid, dinonylnaphthalenedisulfonic acid, complexes of organometallic compounds including tin, zinc, or bismuth, such as stannous octanoate, butylstannic acid, dibutyltin dilaurate (DBTL), dibutyltin diacetate, mercaptolated dibutyltin, dibutyltin dimaleate, dibutyltin diacetate, dimethyltin diacetate, dimethyltin dilaurate, 1,4-diazabicyclo[2.2.2]octane, and bismuth carboxylate, etc.

[0128] Alternatively, the corresponding coating composition (i.e., primer composition or clear coat composition) may be substantially free of catalyst. As used in this specification (including the claims), "substantially free" means that the compound is not intentionally present in the corresponding coating composition; if a compound is present in the corresponding coating composition, its incidental presence is less than 0.1 wt.%, typically less than trace amounts, i.e., less than 100 ppm, based on the total weight of the corresponding coating composition (i.e., primer composition or clear coat composition).

[0129] As used herein, the term "adhesion promoter" refers to any material, when included in a coating composition, that enhances the adhesion of the coating composition to a substrate compared to suitable examples of adhesion promoters, including but not limited to free acids, phosphated epoxy resins, or alkoxysilanes. As used herein, the term "free acid" is intended to cover organic and / or inorganic acids contained as a separate component of the composition, and not any acid that can be used to form polymers that may be present in the corresponding composition. Free acids may include tannic acid, gallic acid, phosphoric acid, phosphorous acid, citric acid, malonic acid, derivatives thereof, or mixtures thereof. Suitable derivatives include esters, amides, and / or metal complexes of such acids.

[0130] The corresponding coating composition (i.e., primer composition or clear coat composition) can be a one-component (1K) coating composition or a two-component (2K) coating composition. Suitably, the corresponding coating composition (i.e., primer composition or clear coat composition) can be a two-component (2K) coating composition. As used herein, a "one-component" or "1K" coating composition is a composition in which all components can be premixed and stored in a single container, and in which the reactive component is not readily reactive at ambient temperature (e.g., temperatures in the range of 20°C to 25°C) or slightly elevated temperature (e.g., temperatures in the range of 25°C to 60°C), but only reacts upon activation by an external energy source. External energy sources that can be used to promote the curing reaction include, for example, radiation (i.e., photochemical radiation) and / or heat. As used herein, a "two-component" or "2K" coating composition is a composition in which at least a portion of the reactive component readily reacts and at least partially cures upon mixing at ambient temperature (e.g., temperatures in the range of 20°C to 25°C) or slightly elevated temperature (e.g., temperatures in the range of 25°C to 60°C). Those skilled in the art will understand that the two components of the coating composition are stored separately from each other and are mixed only before the coating composition is applied.

[0131] As used in conjunction with the coating compositions described herein, the terms “cured,” “cured,” or similar terms mean that at least a portion of the components forming the coating composition are crosslinked to form a coating. Curing or degree of curing can also be determined by dynamic mechanical-thermal analysis (DMTA) under nitrogen using a Polymer Laboratories MK III DMTA analyzer, wherein the degree of curing can be, for example, at least 10% of complete crosslinking as determined by DMTA, such as at least 30%, at least 50%, at least 70%, or at least 90%.

[0132] The primer composition and the clear coat composition can be applied to the substrate and cured together. It is advantageous to allow the primer to dry before applying the clear coat composition.

[0133] Therefore, the drying in steps (A) and / or (B) can be carried out at a temperature in the range of 30 to 80°C, and / or the curing in steps (A) and / or (B) can be carried out at a temperature in the range of 80 to 140°C.

[0134] The method may further include forming an electrodeposited coating on at least a portion of a substrate by depositing an electrodeposited coating composition on at least a portion of the substrate, wherein the electrodeposited coating is positioned between an undercoat and the substrate.

[0135] The method may further include forming a primer or second base coat on at least a portion of the substrate by depositing a primer composition or a second base coat composition on at least a portion of the substrate, wherein the primer or second base coat (e) is positioned between the base coat (b) and the substrate (a), or the primer or second base coat (e) is positioned between the base coat (b) and the electrodeposited coating (d).

[0136] Transparent coating compositions containing titanium dioxide having a volume average particle size Dv50 in the range of 1 to 250 nm can be used to provide multilayer coating compositions that exhibit a novel milky white effect and a large color range compared to standard transparent coatings that do not contain said titanium dioxide having a volume average particle size Dv50 in the range of 1 to 250 nm.

[0137] Therefore, the use of a transparent coating composition for forming a transparent coating on a base layer is provided, the transparent coating composition comprising, based on the total solids content of the transparent coating composition, 0.01 wt.% to 1.50 wt.% of titanium dioxide having a volume average particle size Dv50 in the range of 1 to 250 nm, wherein the base layer has a color flutter index of at least 1.

[0138] The aforementioned primer and clear coat compositions can also be provided as kits suitable for forming multilayer coatings on substrates.

[0139] Furthermore, a multilayer coating can be provided by applying a laminate to a substrate. Thus, a protective film, particularly a removable protective film, can be coated with a transparent coating applied over at least a portion of a base coat, wherein, based on the total weight of the transparent coating, it comprises 0.01 wt.% to 1.50 wt.% titanium dioxide having a volume average particle size Dv50 in the range of 1 to 250 nm, and the dry film thickness of the transparent coating is in the range of 15 to 80 μm. The base coat is then optionally applied. The laminate can then be applied to a substrate such as a surface, particularly the surface of a car. This surface can be a coated surface comprising a base coat and a transparent coating, wherein the base coat has a dry film thickness in the range of 5 to 35 μm, and wherein the base coat contains an angle-dependent color pigment. In other words, the laminate can be used on a coated surface or a coated car. The base coat of the laminate may also already have a dry film thickness in the range of 5 to 35 μm and contain an angle-dependent color pigment.

[0140] The definitions mentioned for multilayer coatings, such as the definitions of primer and / or clear coating, also apply to laminates. For example, the above definition of titanium dioxide also applies to the clear coating of laminates. Therefore, the primer can be the primer as described in this disclosure. Therefore, the clear coating can be the clear coating as described in this disclosure.

[0141] Laminates can be applied to substrates such as coated substrates, multi-coated substrates, or uncoated substrates (such as the surface of a vehicle). Adhesives can be used to apply the laminates to the substrate. Alternatively, an adhesive layer may be present. Specifically, the adhesive layer is present between the substrate and the primer. Specifically, the adhesive layer is present between the liner and the primer. Specifically, the adhesive layer is present between the second protective film and the primer. The primer may also contain adhesive.

[0142] A liner may be applied to at least a portion of the adhesive layer. Typically, a laminate is applied by removing the liner (e.g., a removable liner) to allow the remaining primer and clear coat to be applied to the surface to be laminated (i.e., the substrate). It is desirable to apply the primer to the surface to be coated, particularly using an adhesive applied to the primer and / or to the surface to be coated, or using an adhesive layer applied to at least a portion of the primer.

[0143] Furthermore, a second protective film, particularly a second removable protective film, can be applied to at least a portion of the base coating. Additionally, the second protective film, particularly a second removable protective film, can be applied to at least a portion of the adhesive layer.

[0144] Multilayer coatings can also be multiple layers in which laminates have been applied to the coating surface.

[0145] Therefore, the multilayer coating may comprise, in the following order, a substrate, a base coat applied to at least a portion of the substrate, a second transparent coating applied to at least a portion of the base coat, and a transparent coating, wherein the dry film thickness of the base coat is in the range of 5 to 35 μm, and wherein the base coat comprises an angle-dependent color pigment, wherein, based on the total weight of the transparent coating, the transparent coating comprises 0.01 wt.% to 1.50 wt.% of titanium dioxide having a volume average particle size Dv50 in the range of 1 to 250 nm, and wherein the dry film thickness of the transparent coating is in the range of 15 to 80 μm.

[0146] Therefore, the multilayer coating may comprise, in the following order, a substrate, a base coat applied to at least a portion of the substrate, a second clear coat applied to at least a portion of the base coat, an adhesive layer, and a clear coat, wherein the dry film thickness of the base coat is in the range of 5 to 35 μm, and wherein the base coat comprises an angle-dependent color pigment, wherein, based on the total weight of the clear coat, the clear coat comprises 0.01 wt.% to 1.50 wt.% of titanium dioxide having a volume average particle size Dv50 in the range of 1 to 250 nm, and wherein the dry film thickness of the clear coat is in the range of 15 to 80 μm.

[0147] Therefore, the multilayer coating may comprise, in the following order: a substrate, a base coat applied to at least a portion of the substrate, a second clear coat applied to at least a portion of the base coat, an adhesive layer, another base coat, and a clear coat, wherein the dry film thickness of the base coat is in the range of 5 to 35 μm, and wherein the base coat contains an angle-dependent color pigment, wherein, based on the total weight of the clear coat, the clear coat contains 0.01 wt.% to 1.50 wt.% of titanium dioxide having a volume average particle size Dv50 in the range of 1 to 250 nm, and the dry film thickness of the clear coat is in the range of 15 to 80 μm.

[0148] Therefore, the multilayer coating may comprise, in the following order, a substrate, an adhesive layer and a base coat applied to at least a portion of the substrate, a second transparent coating applied to at least a portion of the base coat, and a transparent coating, wherein the dry film thickness of the base coat is in the range of 5 to 35 μm, and wherein the base coat comprises an angle-dependent color pigment, wherein, based on the total weight of the transparent coating, the transparent coating comprises 0.01 wt.% to 1.50 wt.% of titanium dioxide having a volume average particle size Dv50 in the range of 1 to 250 nm, and the dry film thickness of the transparent coating is in the range of 15 to 80 μm.

[0149] Therefore, the multilayer coating may comprise, in the following order, a substrate, an adhesive layer and a primer applied to at least a portion of the substrate, and a transparent coating applied to at least a portion of the primer, wherein the dry film thickness of the primer is in the range of 5 to 35 μm, and wherein the primer contains an angle-dependent color pigment, wherein, based on the total weight of the transparent coating, the transparent coating contains 0.01 wt.% to 1.50 wt.% of titanium dioxide having a volume average particle size Dv50 in the range of 1 to 250 nm, and the dry film thickness of the transparent coating is in the range of 15 to 80 μm.

[0150] Therefore, the multilayer coating may comprise, in the following order, a substrate, an adhesive layer applied to at least a portion of the substrate, a carrier film and a primer, and a transparent coating applied to at least a portion of the primer, wherein the dry film thickness of the primer is in the range of 5 to 35 μm, and wherein the primer contains an angle-dependent color pigment, wherein, based on the total weight of the transparent coating, the transparent coating contains 0.01 wt.% to 1.50 wt.% of titanium dioxide having a volume average particle size Dv50 in the range of 1 to 250 nm, and the dry film thickness of the transparent coating is in the range of 15 to 80 μm.

[0151] The additional base coat and second clear coat can be any conventional base coat or clear coat, or the base coat and clear coat as described in this disclosure.

[0152] The multilayer coating may include a second clear coating, which is applied to at least a portion of the base coating (b) such that the second clear coating is positioned between the base coating (b) and the clear coating (c). The multilayer coating may include an adhesive layer, which is applied to at least a portion of the second clear coating such that the adhesive layer is positioned between the second clear coating and the clear coating (c).

[0153] It is desirable that the adhesive or adhesive layer and / or additional primer coating be transparent. The dry film thickness of the additional primer coating can be 5 to 35 μm. The dry film thickness of the adhesive layer can be 2 to 35 μm.

[0154] In addition, a laminate is provided comprising: (i) a protective film, particularly a removable protective film; (ii) a transparent coating applied to at least a portion of the protective film, wherein, based on the total weight of the transparent coating, the transparent coating comprises 0.01 wt.% to 1.50 wt.% of titanium dioxide having a volume average particle size Dv50 in the range of 1 to 250 nm, and the dry film thickness of the transparent coating is in the range of 15 to 80 μm; (iii) an optional undercoat applied to at least a portion of the transparent coating, wherein, particularly, the dry film thickness of the undercoat is in the range of 5 to 35 μm, and wherein the undercoat particularly comprises an angle-dependent color pigment; (iv) an optional carrier film applied to at least a portion of the undercoat; (v) an optional adhesive layer applied to at least a portion of the transparent coating, the undercoat, and / or the carrier film; and (vi) an optional liner applied to at least a portion of the adhesive layer.

[0155] In addition, a laminate may be provided comprising, in the following order: (i) a protective film, particularly a removable protective film; (ii) a transparent coating, wherein, based on the total weight of the transparent coating, the transparent coating comprises 0.01 wt.% to 1.50 wt.% of titanium dioxide having a volume average particle size Dv50 in the range of 1 to 250 nm, and the dry film thickness of the transparent coating is in the range of 15 to 80 μm; (iii) an optional undercoat, wherein, in particular, the dry film thickness of the undercoat is in the range of 5 to 35 μm, and wherein the undercoat comprises an angle-dependent color pigment; (iv) an optional carrier film; (v) an optional adhesive layer; and (vi) an optional liner.

[0156] In addition, a laminate may be provided comprising: a protective film, particularly (i) a removable protective film, (ii) a transparent coating applied to at least a portion of the protective film, wherein, based on the total weight of the transparent coating, the transparent coating comprises 0.01 wt.% to 1.50 wt.% of titanium dioxide having a volume average particle size Dv50 in the range of 1 to 250 nm, and the dry film thickness of the transparent coating is in the range of 15 to 80 μm, (iii) an optional undercoat applied to at least a portion of the transparent coating, particularly the dry film thickness of the undercoat is in the range of 5 to 35 μm, and wherein the undercoat particularly comprises an angle-dependent color pigment, (iv) an optional carrier film applied to at least a portion of the undercoat, (v) an optional adhesive layer applied to at least a portion of the transparent coating, the undercoat, and / or the carrier film, and (vi) an optional second protective film applied to at least a portion of the adhesive layer, particularly a second removable protective film.

[0157] A laminate may be provided comprising: a protective film, particularly (i) a removable protective film, (ii) a transparent coating applied to at least a portion of the protective film, wherein, based on the total weight of the transparent coating, the transparent coating comprises 0.01 wt.% to 1.50 wt.% of titanium dioxide having a volume average particle size Dv50 in the range of 1 to 250 nm, and the dry film thickness of the transparent coating is in the range of 15 to 80 μm, (iii) a base coat applied to at least a portion of the transparent coating, particularly wherein the dry film thickness of the base coat is in the range of 5 to 35 μm, and wherein the base coat particularly comprises an angle-dependent color pigment, (iv) a carrier film applied to at least a portion of the base coat, (v) an adhesive layer applied to at least a portion of the transparent coating, the base coat, and / or the carrier film, and (vi) an optional liner applied to at least a portion of the adhesive layer.

[0158] The liner is typically a removable liner. It is usually removed before the laminate is applied to the substrate.

[0159] A laminate may be provided comprising: (i) a removable protective film; (ii) a transparent coating applied to at least a portion of the protective film, wherein, based on the total weight of the transparent coating, the transparent coating comprises 0.01 wt.% to 1.50 wt.% titanium dioxide having a volume average particle size Dv50 in the range of 1 to 250 nm, and the dry film thickness of the transparent coating is in the range of 15 to 80 μm; (iii) a base coat applied to at least a portion of the transparent coating, wherein the dry film thickness of the base coat is in the range of 5 to 35 μm, and wherein the base coat particularly comprises an angle-dependent color pigment; (iv) an optional carrier film applied to at least a portion of the base coat; (v) an adhesive layer applied to at least a portion of the transparent coating, the base coat, and / or the carrier film; and (vi) an optional liner applied to at least a portion of the adhesive layer. The liner is generally a removable liner. The liner is typically removed before the laminate is applied to the surface.

[0160] The thickness of the carrier membrane can range from 20 μm to 150 μm, such as 30 to 40 μm or 120 to 140 μm. The carrier membrane can be a plastic membrane, such as polypropylene.

[0161] The carrier film of the laminate can be a plastic, specifically selected from fluoropolymers such as ethylene tetrafluoroethylene (ETFE), polyethylene terephthalate, polyolefins, polycarbonate, acrylonitrile-butadiene-styrene (ABS), styrene-acrylonitrile acrylate (ASA), acrylonitrile-butadiene-styrene / polycarbonate (ABS / PC), styrene-acrylonitrile acrylate / polycarbonate (ASA / PC), polycarbonate / polybutylene terephthalate (PC / PBT), polyacrylate, polystyrene, and / or polymethyl methacrylate.

[0162] The (removable) protective film of the laminate can be plastic, specifically selected from fluoropolymers such as ethylene tetrafluoroethylene (ETFE), polyethylene terephthalate, polyolefins, polycarbonate, acrylonitrile-butadiene-styrene (ABS), styrene-acrylonitrile acrylate (ASA), acrylonitrile-butadiene-styrene / polycarbonate (ABS / PC), styrene-acrylic acid-butadiene-acrylonitrile acrylate / polycarbonate (ASA / PC), polycarbonate / polybutylene terephthalate (PC / PBT), polyacrylate, polystyrene, and / or polymethyl methacrylate.

[0163] The second (removable) protective film of the laminate can be plastic, specifically selected from fluoropolymers such as ethylene tetrafluoroethylene (ETFE), polyethylene terephthalate, polyolefins, polycarbonate, acrylonitrile-butadiene-styrene (ABS), styrene-acrylonitrile acrylate (ASA), acrylonitrile-butadiene-styrene / polycarbonate (ABS / PC), styrene-acrylic acid-butadiene-acrylonitrile acrylate / polycarbonate (ASA / PC), polycarbonate / polybutylene terephthalate (PC / PBT), polyacrylate, polystyrene, and / or polymethyl methacrylate.

[0164] Furthermore, a method for applying a laminate to a substrate is provided, comprising: (I) providing a laminate according to the present disclosure; (II) contacting the substrate with the laminate, wherein the substrate particularly comprises an undercoat applied to at least a portion of the substrate, wherein the dry film thickness of the undercoat is in the range of 5 to 35 μm, and wherein the undercoat comprises an angle-dependent color pigment; and (III) optionally applying an adhesive to the substrate prior to contacting the substrate with the laminate, such that the laminate is applied to the adhesive. For example, the substrate may be a coated surface of a vehicle or an uncoated surface of a vehicle.

[0165] Examples of laminates can be found in WO 2009 / 024310 A1.

[0166] This disclosure will now be described with reference to the accompanying drawings, which do not limit the scope or limits of this disclosure. The description provided is offered purely by way of example and illustration.

[0167] Figure 1 A multilayer coating (100) is shown, comprising a substrate (101), a base coat (102), and a clear coat (103), each coating according to this disclosure. The base coat (102) typically contains an angle-dependent color pigment and may have a chromatic aberration index of at least 1. Based on the total weight of the clear coat, the clear coat (103) contains 0.01 wt.% to 1.50 wt.% titanium dioxide having a volume average particle size Dv50 in the range of 1 to 250 nm. As can be seen from the figure, the base coat (102) is applied directly to the substrate. However, a second base coat (not shown) or primer (not shown) may be present between the substrate (101) and the base coat (102).

[0168] Figure 2aA multilayer coating (200a) is shown, comprising a substrate (101), a base coat (102), and a clear coat (103), each according to the present disclosure. Furthermore, a second clear coat (104) is present between the base coat (102) and the adhesive layer (105). A removable protective film (106) is present on top of the clear coat (103). Typically, finished multilayer coatings no longer include a removable protective film. Figure 2a The removable protective film (106), the transparent coating (103), and the adhesive layer (105) represent a laminate applied to a coated substrate containing a substrate (101), a base coating (102), and a second transparent coating (104).

[0169] Figure 2b A method is shown in which a laminate comprising a removable protective film (106), a clear coating (103), an adhesive layer (105), and a liner (107) is applied to a coated substrate comprising a substrate (101), a base coating (102), and a second clear coating (104). The liner (107) is removed, and then the laminate is applied on top of the second clear coating (104). The removable protective film (106) can be removed.

[0170] Figure 3 Another laminate was revealed, comprising a removable protective film (106), a clear coating (103), a base coating (102), a carrier film (108), an adhesive layer (105), and a liner (107).

[0171] Example

[0172] The following examples are for illustrative purposes only and are not limited to those examples. Unless otherwise stated, all temperatures are 22°C, all pressures are 1 atm, and the relative humidity is 30%. Although the numerical ranges and parameters illustrating the broad scope of this disclosure are approximate, the values ​​described in the specific examples are reported as accurately as possible. Any numerical value inherently contains some error that is necessarily caused by the standard deviation found in its corresponding test measurement results. Unless otherwise indicated, all parts and percentages in the examples are by weight.

[0173] The specific features illustrated in the examples may be used to further limit the scope of this disclosure.

[0174] The dry film thickness was measured using a non-destructive coating thickness measuring device, “LAYERCHECK 750 USB” (ERICHSEN GmbH & Co. KG, Germany), employing the magnetic induction method. The film thickness determination followed DIN EN ISO 2808.

[0175] The optical properties (such as color flutter index, L*, a*, b*) of the coating (particularly the multilayer coating stack or undercoat according to this disclosure) were measured using a BYK-mac i multi-angle spectrophotometer (manufactured by BYK) and specifically following the instructions in the instrument manual. The BYK-mac i performed color measurements at 5 angles for light / dark path evaluation: 15° / 25° / 45° / 75° / 110°. Color calculations and measurements were performed in accordance with DIN EN ISO 11664 (2020-03) standard (1-4). The color flutter index was calculated as follows:

[0176]

[0177] Color range is calculated using the following formula

[0178]

[0179] The color shift Δb* is calculated as follows:

[0180]

[0181] The color shift Δa* is calculated as follows:

[0182]

[0183] Pigment weight concentration (PWC) is calculated as follows:

[0184]

[0185] The pigments in the coating composition refer to the total weight of pigments, and the binder refers to the total weight of binders in the coating composition. The binder includes all film-forming resins and all crosslinking agents. Crosslinking agents, for example, are polyisocyanates.

[0186] A. Preparation of primer composition

[0187] The primer composition according to this disclosure is prepared by mixing the components listed in Table 1 under stirring.

[0188] Table 1: Primer compositions used to prepare the base coat

[0189]

[0190] 1 Polyurethane acrylic latex—a polymer of Example IIA described in U.S. Patent No. 5,972,809.

[0191] 2An acrylic dispersion was prepared from 30.0 wt% styrene, 35.0 wt% n-butyl acrylate, 18.0 wt% n-butyl methacrylate, 8.5 wt% 2-hydroxyethyl acrylate and 8.5 wt% acrylic acid in a mixture of 84.5 wt% deionized water and 15.5 wt% butyl carbitol solvent, with 26.1% by weight solids, and neutralized by 54% with dimethylethanolamine.

[0192] 3 Polyester resin—the polymer of Example 2 described in U.S. Patent No. 5,468,802.

[0193] 4 Dimethylethanolamine (50% aqueous solution)

[0194] 5 A phosphorylated epoxy resin prepared from Epon 828, which is available from Shell Chemical Co., and bisphenol A polyglycidyl ether; reacted with phosphoric acid at a weight ratio of 83:18.

[0195] 6 Additives available from Byk Chemie.

[0196] 7 Polyether polyols are available from Bayer Material Science.

[0197] 8 Melamine curing agent is commercially available from INEOS Melamine.

[0198] 9,10 Solvents available from Dow Co.

[0199] 11 Solvents available from Shell Chemical Co.

[0200] 12 Surfactants available from Air Products & Chemicals.

[0201] 13The following are corresponding primer color pastes with a solids content of 46%. Primer "Silver" is prepared using silver color paste. Primer "Purple" is prepared using purple color paste. Primer "Blue" is prepared using blue color paste. Primer "Blue 2" is prepared using blue 2 color paste. Primer "Beige" is prepared using beige color paste. Primer "Dark Green" is prepared using dark green color paste. Primer "Brown" is prepared using brown color paste. Primer "Green" is prepared using green color paste. Primer "Dark Blue" is prepared using dark blue color paste.

[0202] 14 A dispersion of 9% Aerosil R812 in a 21% acrylic polymer blend obtained commercially from Evonik Degussa, with a solids content of 31%.

[0203] The color paste was prepared using "Disperser DAS H [ / A] 200-K mit Kühleinrichtung - SYSTEM LAU" (LAUGmbH, Germany, Prüfgeräte für Oberflächenschutz, lau-hemer.de).

[0204] The silver pigment has a solids content of 46% and uses aluminum flakes as the sole pigment.

[0205] The aluminum sheet provides the desired aluminosity index for the base coating. Comparative Example 43 illustrates the optical properties of a silver base coating, wherein a standard clear coating without pigment is applied over the silver base coating.

[0206] The purple pigment has a solids content of 46% and contains 18 wt.% (based on total pigment content) of aluminum flakes as an angle-dependent color pigment, purple mica, and TiO2 with a Dv50 of 20 μm.

[0207] The blue pigment has a solids content of 46% and contains 16 wt.% (based on total pigment content) aluminum flakes as an angle-dependent color pigment and blue mica.

[0208] Blue 2 color paste has a solids content of 46% and contains 80 wt.% (based on total pigment content) of aluminum flakes, blue mica and iron oxide red (PR101) as angle-dependent color pigments.

[0209] The beige pigment has a solids content of 46% and contains 44 wt.% (based on total pigment content) of aluminum flakes, mica copper, TiO2 with a Dv50 of 20 μm, and iron oxide red (PR101) as an angle-dependent color pigment.

[0210] The dark green pigment has a solids content of 46% and contains 23 wt.% (based on total pigment content) aluminum flakes and green mica as an angle-dependent color pigment.

[0211] The brown pigment has a solids content of 46% and contains 40 wt.% (based on total pigment content) aluminum flakes, blue mica, and iron oxide red (PR101) as angle-dependent pigments.

[0212] The green pigment has a solids content of 46% and contains 33 wt.% (based on total pigment content) of aluminum flakes and green mica as an angle-dependent color pigment.

[0213] The deep blue pigment has a solids content of 46% and contains 15 wt.% (based on total pigment content) aluminum flakes, blue mica, and TiO2 with a Dv50 of 20 µm as an angle-dependent pigment.

[0214] B. Preparation of color paste for transparent coating compositions

[0215] The color paste was prepared using "Disperser DAS H [ / A] 200-K mit Kühleinrichtung - SYSTEM LAU" (LAUGmbH, Germany, Prüfgeräte für Oberflächenschutz, lau-hemer.de).

[0216] White transparent pigment paste 1 is formed from a blend of 67 wt.% titanium dioxide with a Dv50 of 20 μm dispersed in 10.3 wt.% polyester resin and 4.4 wt.% melamine resin with a solids content of 84 wt.%. The solvent is butyl acetate. The titanium dioxide in pigment paste 1 has a rutile crystal structure and an oil absorption of 18 (g / 100g pigment) according to DIN ISO 787-10, with a BET surface area (m²). 2 The titanium dioxide ( / g) (measured by Brunauer-Emmert-Teller theory / DIN ISO 9277:2003-05) is 13 to 14. The titanium dioxide in pigment 1 is commercially available titanium dioxide Tiona 595 from Tronox US Holdings Inc.

[0217] Transparent pigment paste 2 is formed from a blend of 40 wt.% titanium dioxide with a Dv50 of 50 nm dispersed in 20.2 wt.% polyester resin and 8.5 wt.% melamine resin with a solids content of 75 wt.%. The solvent is butyl acetate. The titanium dioxide in pigment paste 2 has a rutile crystal structure and an oil absorption of 30 to 40 g / 100 g pigment according to DIN ISO 787-10, with a BET surface area (m²). 2 The titanium dioxide content (g) (measured according to Brunauer-Emmert-Teller theory / DIN ISO 9277:2003-05) is 35. The titanium dioxide in pigment 2 is titanium dioxide MT-700HD, which is commercially available from TAYCA Ltd.

[0218] Except for the 2 mm diameter glass beads, add the above-mentioned materials for each color paste, along with half the solvent (excluding melamine resin), to a glass bottle. Shake the mixture for 60 minutes using the disperser described above. Add the melamine resin and the remaining half of the solvent and shake again for 2 minutes. The material to glass beads ratio should be 1:2.25. The grinding fineness of each color paste size should be approximately 5 to 8 micrometers (7.5 µm for color paste 1 and 8 µm for color paste 2). Filter the resulting color pastes and use them in the following examples.

[0219] The above-mentioned grinding fineness was measured using a Hegman Model 232-25 grinder (from Erichsen, ERICHSEN GmbH & Co. KG, Germany). The grinding fineness was obtained according to DIN 53 203, DIN EN 21 524, and ISO 1524. A liquid wedge of the test material was generated on the testing apparatus. If the grain size is larger than the local wedge thickness, it is easily detected visually. At the boundary between the disturbed and smooth liquid surfaces, the operator can read the relevant wedge thickness, which indicates the grinding fineness.

[0220] C. Preparation of two-component (2K) transparent coating compositions

[0221] The 2K clear coating composition according to this disclosure is prepared by preparing components A and B listed in Table 2. The 2K coating composition is prepared by mixing components A and B of Table 2 (weight ratio of component A to component B 2:1). In Table 2, the weight percentages based on the total composition are indicated for the final and mixed clear coating compositions.

[0222] Table 2: 2K Coating Compositions

[0223]

[0224] 15 Hydroxyl value: 150, OH%: 4.55, Solid content: 60, Tg [°C]: -5

[0225] 16 Setalux 91767 VX-60, OH%: 4.5%, solids content: 60%, is commercially available from Allnex (Germany).

[0226] 17 Hydroxyl value: 290, OH%: 8.79, Solid content: 78, Tg [°C]: -16

[0227] 18 Cymel 1156 is available from Allnex (Germany).

[0228] 19 Tinuvin 928 is available from BASF (Germany).

[0229] 20 Tinuvin 123 is available from BASF (Germany).

[0230] 21 Bykn 322 is available from Byk (Germany);

[0231] 22 Byk 390 is available from Byk (Germany)

[0232] 23 Nacure 5528, available commercially from King Industries Inc. (USA), has a solids content of 25%.

[0233] 24 Aromatic 100, commercially available from ExxonMobil (USA); isoamyl acetate, n-butyl acetate; ethyl 3-ethoxypropionate; diethylene glycol butyl ether acetate, 2-butoxyethyl acetate

[0234] 25 Color paste 1 as described in item B.

[0235] 26 Color paste 2 as described in item B.

[0236] 27 Desmodur ultra N 3390 BA / SN, available commercially from Covestro (Germany), solids content: 90%.

[0237] 28Solvesso 100 is available commercially from ExxonMobil (USA).

[0238] The hydroxyl value and hydroxyl content (OH%) of the acrylic resin were determined according to DIN EN ISO 4629-1:2016. The glass transition temperature (Tg) was determined according to DIN EN ISO 16805:2005.

[0239] D. Preparation of multilayer coatings

[0240] According to Table 3, in each example, the primer composition shown in Table 1 was sprayed onto an E-coated steel substrate, available from ACT Test Panels LLC (USA), using a Satajet 100BFRP spray gun (available from SATA GmbH & Co (Germany)). The film thickness of the primer composition was selected such that the dry film thickness was within the range specified in Table 3. The primer composition was then dried at 80°C for 10 minutes. The clear coating composition shown in Table 2 was sprayed onto the primer using a Satajet 100BFRP spray gun (available from SATA GmbH & Co (Germany)) such that the dry film thickness was within the range specified in Table 3. The substrate coated with the coating composition was cured using hot air in an oven (HORO Dr. Hofmann GmbH (Germany)). The substrate was cured at 140°C for 20 minutes.

[0241] Table 3: Multilayer coatings using 2K clear coating compositions

[0242]

[0243] 29 Standard TiO2 and Tiona 595 / Tronox were added as pigment 1.

[0244] 30 nTiO2: Micro MT-700HD from TAYCA Ltd., added as colorant 2.

[0245] 31 Basecoat Violet also contains 4.73 wt.% nTiO2.

[0246] Comparative Example 1 shows that simply adding titanium dioxide with a volume average particle size Dv50 in the range of 1 to 250 nm to the primer requires a very high amount of said titanium dioxide in order to exhibit at least a weak color path. However, a large amount of titanium dioxide in the primer results in a strong white color in the primer.

[0247] In Comparative Examples 2 to 4, standard titanium dioxide was used in the transparent coating. No milky white effect was observed; only white color changes were observed in the multilayer coatings.

[0248] Examples 5 through 14 show that the addition of titanium dioxide with a volume average particle size Dv50 in the range of 1 to 250 nm to transparent coatings results in strong color range, strong Δb* variation and milky white effect.

[0249] According to Table 4, in each example, the primer composition shown in Table 1 was sprayed onto an E-coated steel substrate, available from ACT Test Panels LLC (USA), using a Satajet 100BFRP spray gun, available from SATA GmbH & Co (Germany). The film thickness of the primer composition was selected such that the dry film thickness was within the range specified in Table 4. The primer composition was then dried at 80°C for 10 minutes. A 1K clear coating composition was sprayed onto the primer using a Satajet 100BFRP spray gun, available from SATA GmbH & Co (Germany), such that the dry film thickness was within the range specified in Table 4. Each 1K clear coating composition shown in Table 4 contains the required amount (0.01 wt.% to 1.50 wt.%) of titanium dioxide having a volume average particle size Dv50 in the range of 1 to 250 nm. The substrate coated with the coating composition was cured using hot air in an oven (HORO Dr. Hofmann GmbH (Germany)). The substrate was cured at 140°C for 20 minutes.

[0250] Table 4: Multilayer coatings using 1K clear coating compositions

[0251]

[0252] 30 nTiO2: Micro MT-700HD from TAYCA Ltd., added as colorant 2.

[0253] Examples 15 to 32 also reveal the relationship between the dry film thickness of PWC and clear coatings. A balance should be maintained between film formation and pigment concentration in the clear coating to achieve maximum color range. If a high pigment concentration in the clear coating is desired, the dry film thickness should be reduced.

[0254] In Table 5, a standard transparent coating without pigments is applied to an effect base coating containing angle-dependent color pigments and directly compared with a transparent coating according to the present disclosure containing 0.01 wt.% to 1.50 wt.% of titanium dioxide having a volume average particle size Dv50 in the range of 1 to 250 nm.

[0255] As can be seen from Table 5, the chromatic aberration index is reduced by using the transparent coating according to this disclosure, but a strong chromatic aberration is observed, in particular a strong Δb* shift, and a milky white effect (see Examples 12, 34, 36, 38, 40 and 42).

[0256] Table 5: Comparison of multilayer coatings containing standard clear coating

[0257]

[0258] Although specific examples of this disclosure have been described above for illustrative purposes, it will be apparent to those skilled in the art that many changes may be made to the details of this disclosure without departing from the scope of the disclosure as defined in the appended claims.

Claims

1. A multilayer coating comprising: (a) Substrate, (b) A base coating applied to at least a portion of the substrate, wherein the dry film thickness of the base coating is in the range of 5 to 35 μm, and wherein the base coating comprises an angle-dependent color pigment. (c) A transparent coating applied to at least a portion of the base coating, wherein the transparent coating comprises 0.01 wt.% to 1.50 wt.% titanium dioxide, having a volume average particle size Dv50 in the range of 1 to 250 nm, based on the total weight of the transparent coating, and the dry film thickness of the transparent coating is in the range of 15 to 80 μm.

2. The multilayer coating of claim 1, wherein the dry film thickness of the base coating is in the range of 7 to 28 μm, such as 8 to 26 μm, 9 to 25 μm, or 10 to 20 μm, and / or The base coating has a chromatic aberration index of at least 1, and / or The dry film thickness of the transparent coating is in the range of 30 to 70 μm, such as 33 to 65 μm, 35 to 60 μm, or 40 to 50 μm, and / or The multilayer coating has a color flutter index of at least 0.1, and / or The dry film coating thickness of the multilayer coating is in the range of 70 to 200 μm, such as 80 to 160 μm, 90 to 150 μm or 100 to 130 μm.

3. The multilayer coating according to any one of the preceding claims, wherein the multilayer coating comprises a second transparent coating, and the second transparent coating is applied to at least a portion of the base coating (b) such that the second transparent coating is positioned between the base coating (b) and the transparent coating (c), and / or wherein the multilayer coating comprises an adhesive layer, and the adhesive layer is applied to at least a portion of the second transparent coating such that the adhesive layer is positioned between the second transparent coating and the transparent coating (c), and / or wherein the multilayer coating comprises an adhesive layer, and the adhesive layer is applied to at least a portion of the substrate (a) such that the adhesive layer is positioned between the substrate (a) and the base coating (b).

4. The multilayer coating according to any one of the preceding claims, wherein the transparent coating comprises titanium dioxide having a volume average particle size Dv50 in the range of 12 to 80 nm, such as 20 to 70 nm, 30 to 60 nm, or 35 to 55 nm, and / or Based on the total weight of the transparent coating, the transparent coating comprises 0.04 wt.% to 1.30 wt.%, such as 0.09 wt.% to 1.10 wt.%, 0.14 wt.% to 1.00 wt.%, 0.20 wt.% to 0.90 wt.%, 0.25 wt.% to 0.80 wt.%, 0.35 wt.% to 0.70 wt.%, 0.40 wt.% to 0.70 wt.%, 0.50 wt.% to 0.70 wt.%, or 0.50 wt.% to 0.60 wt.%, of titanium dioxide having a volume average particle size Dv50 in the range of 1 to 250 nm.

5. The multilayer coating according to any one of the preceding claims, wherein the pigment weight concentration (PWC) of the transparent coating is 0.01% to 2%, such as 0.05% to 1.8%, 0.1% to 1.3%, 0.2% to 1.1%, 0.25% to 1%, 0.40% to 0.90%, or 0.50% to 0.80%, and / or wherein the ratio of total pigment weight to total base weight is 0.0001 to 0.1, such as 0.0005 to 0.08, 0.0009 to 0.04, 0.001 to 0.03, 0.002 to 0.02, 0.003 to 0.01, 0.004 to 0.009, or 0.005 to 0.

008.

6. The multilayer coating according to any one of the preceding claims, wherein the BET surface area of ​​titanium dioxide in the transparent coating is 20 to 80 m². 2 / g, such as 25 to 70 m 2 / g, 25 to 50 m 2 / g or 30 to 45 mg 2 / g.

7. The multilayer coating according to any one of the preceding claims, wherein the multilayer coating further comprises an electrodeposited coating applied to at least a portion of the substrate, wherein the electrodeposited coating is positioned between the undercoat and the substrate.

8. The multilayer coating according to any one of the preceding claims, wherein the multilayer coating further comprises a primer or a second base coat applied to at least a portion of the substrate, wherein the primer or the second base coat is positioned between the base coat (b) and the substrate, or the primer or the second base coat is positioned between the base coat (b) and the electrodeposited coating.

9. A method for preparing a multilayer coating, particularly a multilayer coating according to any one of the preceding claims, the method comprising, in the following order: (A) A base coating is formed on at least a portion of a substrate by depositing a base coating composition onto at least a portion of the substrate, wherein the base coating composition comprises an angle-dependent color pigment. (B) Optionally, the base coat is dried and / or cured. (C) A transparent coating is formed on at least a portion of the base coat by depositing a transparent coating composition on at least a portion of the substrate, wherein the transparent coating composition comprises 0.01 wt.% to 1.50 wt.% titanium dioxide, the titanium dioxide having a volume average particle size Dv50 in the range of 1 to 250 nm, based on the total solids content of the transparent coating composition. (D) Dry and / or cure the transparent coating or both the base coating and the transparent coating. The dry film thickness of the transparent coating is in the range of 15 to 80 μm, and the dry film thickness of the base coating is in the range of 5 to 35 μm.

10. The method according to any one of claims 9, wherein the drying in step (A) and / or (B) is performed at a temperature in the range of 30°C to 80°C, and / or the curing in step (A) and / or (B) is performed at a temperature in the range of 80°C to 140°C.

11. The method of any one of claims 9 or 10, wherein the method further comprises forming an electrodeposited coating on at least a portion of the substrate by depositing an electrodeposited coating composition on at least a portion of the substrate, wherein the electrodeposited coating is positioned between the undercoating and the substrate, and / or The method further includes forming a primer or second base coat on at least a portion of the substrate by depositing a primer composition or a second base coat composition on at least a portion of the substrate, wherein the primer or second base coat (e) is positioned between the base coat (b) and the substrate (a), or the primer or second base coat (e) is positioned between the base coat (b) and the electrodeposited coating (d).

12. Use of a transparent coating composition to form a transparent coating on a base coat, wherein, based on the total solids content of the transparent coating composition, the transparent coating composition comprises 0.01 wt.% to 1.50 wt.% titanium dioxide having a volume average particle size Dv50 in the range of 1 to 250 nm, wherein the base coat has a color flutter index of at least 1.

13. A laminate comprising: (i) Protective film, especially removable protective film, (ii) A transparent coating applied to at least a portion of the protective film, wherein, based on the total weight of the transparent coating, the transparent coating comprises 0.01 wt.% to 1.50 wt.% titanium dioxide having a volume average particle size Dv50 in the range of 1 to 250 nm, and the dry film thickness of the transparent coating is in the range of 15 to 80 μm. (iii) An optional base coat applied to at least a portion of the transparent coating, wherein, in particular, the dry film thickness of the base coat is in the range of 5 to 35 μm, and wherein the base coat particularly comprises an angle-dependent color pigment. (iv) An optional carrier film applied to at least a portion of the base coating. (v) An optional adhesive layer applied to at least a portion of the transparent coating, primer, and / or carrier film, and (vi) An optional lining applied to at least a portion of the adhesive layer.

14. The laminate of claim 13, wherein the carrier film of the laminate is a plastic, and particularly, the plastic is selected from fluoropolymers such as ethylene tetrafluoroethylene (ETFE), polyethylene terephthalate, polyolefins, polycarbonate, acrylonitrile-butadiene-styrene (ABS), styrene-acrylonitrile acrylate (ASA), acrylonitrile-butadiene-styrene / polycarbonate (ABS / PC), styrene-acrylonitrile acrylate / polycarbonate (ASA / PC), polycarbonate / polybutylene terephthalate (PC / PBT), polyacrylate, polystyrene, and / or polymethyl methacrylate.

15. A method for applying a laminate to a substrate, comprising: (I) Providing a laminate according to any one of claims 13 to 14, (II) Bring the substrate into contact with the laminate. The substrate specifically comprises a base coating applied to at least a portion of the substrate, wherein the dry film thickness of the base coating is in the range of 5 to 35 μm, and wherein the base coating comprises an angle-dependent color pigment. (III) Optionally, the adhesive is applied to the substrate before the substrate is brought into contact with the laminate, such that the laminate is applied to the adhesive.

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