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WO2026022140A1 - Lidar reflective colored coatings - Google Patents

Lidar reflective colored coatings

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Publication number
WO2026022140A1
WO2026022140A1 PCT/EP2025/070978 EP2025070978W WO2026022140A1 WO 2026022140 A1 WO2026022140 A1 WO 2026022140A1 EP 2025070978 W EP2025070978 W EP 2025070978W WO 2026022140 A1 WO2026022140 A1 WO 2026022140A1
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WO
WIPO (PCT)
Prior art keywords
coating
coating composition
present
constituent
optionally
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
PCT/EP2025/070978
Other languages
French (fr)
Inventor
Michaela Liese
Janusch Owtschary
Jari RODEWALD
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
BASF Coatings GmbH
Original Assignee
BASF Coatings GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by BASF Coatings GmbH filed Critical BASF Coatings GmbH
Publication of WO2026022140A1 publication Critical patent/WO2026022140A1/en
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

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    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
    • C09D5/004—Reflecting paints; Signal paints
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
    • C09D7/40—Additives
    • C09D7/41—Organic pigments; Organic dyes
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
    • C09D7/40—Additives
    • C09D7/60—Additives non-macromolecular
    • C09D7/61—Additives non-macromolecular inorganic
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
    • C09D7/40—Additives
    • C09D7/66—Additives characterised by particle size
    • C09D7/68—Particle size between 100-1000 nm
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
    • C09D7/40—Additives
    • C09D7/66—Additives characterised by particle size
    • C09D7/69—Particle size larger than 1000 nm
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
    • C09D7/40—Additives
    • C09D7/70—Additives characterised by shape, e.g. fibres, flakes or microspheres
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
    • G01S17/88—Lidar systems specially adapted for specific applications
    • G01S17/93—Lidar systems specially adapted for specific applications for anti-collision purposes
    • G01S17/931—Lidar systems specially adapted for specific applications for anti-collision purposes of land vehicles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D2202/00—Metallic substrate
    • B05D2202/10—Metallic substrate based on Fe
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D5/00—Processes for applying liquids or other fluent materials to surfaces to obtain special surface effects, finishes or structures
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
    • B05D7/50—Multilayers
    • B05D7/56—Three layers or more
    • B05D7/57—Three layers or more the last layer being a clear coat
    • B05D7/576—Three layers or more the last layer being a clear coat each layer being cured, at least partially, separately
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/18—Oxygen-containing compounds, e.g. metal carbonyls
    • C08K3/20—Oxides; Hydroxides
    • C08K3/22—Oxides; Hydroxides of metals
    • C08K2003/2237—Oxides; Hydroxides of metals of titanium
    • C08K2003/2241—Titanium dioxide
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/01—Use of inorganic substances as compounding ingredients characterized by their specific function
    • C08K3/013—Fillers, pigments or reinforcing additives
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/02—Elements
    • C08K3/04—Carbon
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K5/00—Use of organic ingredients
    • C08K5/0008—Organic ingredients according to more than one of the "one dot" groups of C08K5/01 - C08K5/59
    • C08K5/0041—Optical brightening agents, organic pigments

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Organic Chemistry (AREA)
  • Wood Science & Technology (AREA)
  • Materials Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Nanotechnology (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Remote Sensing (AREA)
  • Radar, Positioning & Navigation (AREA)
  • General Physics & Mathematics (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Inorganic Chemistry (AREA)
  • Paints Or Removers (AREA)

Abstract

The present invention relates to a coating composition comprising at least one film-forming polymer as a1), at least two types of metal effect pigments as a3), at least two types of titanium dioxide pigments having a median particle size Dv50 in a range of from 325 to 1190 nm as a4), at least one type of non-black coloring pigment in an amount of at least 0.015 wt.-%, based on the total weight of the coating composition, as a5), and water and/or one or more organic solvents, as a6), a method of coating of a substrate and a method of preparing a multilayer coating system onto a substrate, each of which makes use of applying said coating composition in one step of each method, a coated substrate obtainable by these methods, a multilayer coating system comprising at least two coatings layers L2 and L3, wherein layer L2 is obtainable from said coating composition, a method of improving the LiDAR reflectivity and/or LiDAR detectability of objects, and to a use of said coated substrate and/or said multilayer coating system and/or said object in LiDAR visibility applications.

Description

LiDAR reflective colored coatings
The present invention relates to a coating composition inter alia comprising three different types of pigments, a method of coating of a substrate and a method of preparing a multilayer coating system onto a substrate, each of which makes use of applying said coating composition in one step of each method, a coated substrate obtainable by these methods, a multilayer coating system comprising at least two coatings layers L2 and L3, wherein layer L2 is obtainable from said coating composition, a method of improving the LiDAR reflectivity and/or LiDAR detectability of objects, and to a use of said coated substrate and/or said multilayer coating system and/or said object in LiDAR visibility applications.
Background of the invention
Recent advances have been made in technologies related to self-driving vehicles and vehicles with ADAS (Advanced Driver Assistance Systems). Vehicles with ADAS decrease driving stress, decrease the number of accidents, improve fuel economy etc. Typically, such technologies require the detection of objects in a vehicle's surroundings. Detecting systems generally comprise sensors, cameras, radar, ultrasonic, and lasers to detect and locate obstacles such that the vehicle can safely navigate around such objects. Some detecting systems are limited in their ability to detect objects at long distances or non-ideal environments, such as in low-light conditions, in inclement weather, such as fog, rain, and snow, or in other conditions with light scattering particulates in the air (e.g., smog and dust). Such limitations may prohibit the vehicles from safely navigating obstacles.
ADAS rely highly rely on remote sensing technologies on optical or electromagnetic means for position and speed determination. LiDAR (Light Detection And Ranging) is a remote-sensing technology that can be deployed within such vehicles as the primary source of object recognition. By illuminating the surrounding environment with laser light (typically 905 nm or 1550 nm) LiDAR maps distance to objects in its path in real-time by measuring the reflection with a sensor and can be paired with software to safely react to objects within their vicinity. For example, if an object gets too close to the vehicle, the software can react to avoid collision with the object. Since LiDAR utilizes near-infrared light (near-IR light or NIR light) as its source of illumination, the technology has to overcome several challenges.
Most of the current coatings are applied to substrates such as vehicle bodies for improved durability and aesthetics, but usually impart no sufficient functionality in reflecting near-IR light for the purposes of greater visibility to LIDAR technology. This shows that apart from the LiDAR instrument, one of the important factors for the accuracy of the measurement of LiDAR reflectivity is the surface of the illuminated object. In case of automobiles and other vehicles, the surface is usually covered by a multilayer coating, which plays an important role in determining the LiDAR reflectivity.
An object's ability to reflect light is dependent on its bulk and surface properties, and manifests itself as specular or diffuse. Specular reflection of light occurs when incident light stemming from a light source in a single direction is reflected into a single outgoing direction at the opposite angle to the plane normal to the reflective surface as the incident wave. Diffuse reflection occurs when incident light stemming from a light source in a single direction is reflected at many angles. In theory, both specular and diffuse reflection can be utilized in LiDAR technology for vehicles, but in practice, this is much more difficult. With specular reflection, much of the luminance is observed at the angle opposite the angle of incidence. Thus, for a moving vehicle with a detector positioned at the light source, this could prove problematic if the angle of incidence was positioned away from the tandem light source and detector. For metallic paints, typically at low incident angles of, e.g., 0° to 10°, LiDAR reflectivity is at its maximum, LiDAR reflectivity significantly drops at higher incident angles, such as an incident angle of 35° or higher from the plane normal to the reflective surface. Dark non-metallic paints do have the tendency to have a low LiDAR reflectivity along the entire incidence angle range.
In particular, silver and/or dark colored coatings, particularly coatings containing metal effect pigments such as aluminum flake pigments, need to be improved at higher incidence angles and dark non-metallic colors also at lower angles.
Metal effect pigments are typically contained in a basecoat layer, which is part of a multilayer coating system being present on a surface of a suitable substrate, in order to provide said multilayer coating system with a so-called lightness flop effect, particularly in form of a silver-metallic multilayer coating system. The term "lightness flop" (or just flop as used herein), expressed by the so-called flop index, refers to the difference between the amount or hue of light reflected at different angles from a metallic coating surface. Although the most desired platelet-shaped metallic pigments are typically highly reflective and coatings obtained by using such pigments typically have a high flop index, they also exhibit a very specular reflectivity and therefore have an only low reflectivity in the off-specular angle range, which adversely affects the LiDAR reflectivity from those vehicles, which are not directly in front of the light source/detector system, but at an angle or in adjacent lane thereto.
Furthermore, besides the lightness flop effect, also the so-called sparkling effect plays a significant role in metal effect pigment containing multilayer coating systems, which can be observed under direct sun light. This effect is often described with different words such as sparkle, sparkling, micro brilliance or glint and is generated by the reflectivity of individual metal effect pigments. The sparkle is influenced by the flake type and size, concentration level of the metal effect pigment, orientation of the metal effect pigment and application method. For a given type and size of the metal effect pigment, a given concentration level and application method, it is, as for the flop index, the orientation of the metal effect pigment which influences the sparkle.
Consequently, coatings such as conventional multilayer coating systems obtainable by use of conventional metal effect pigment containing coating compositions show a rather high flop index of 9 and above and sparkle points per area at an illumination angle of 15° of about 20 and more, while their LIDAR reflectivity at an angle of incidence of 60° is often below 5% or even lower, which is undesired. In addition, if further non-metallic pigments such as nonblack coloring pigments are introduced into the metal effect pigment containing coatings, they also have an impact on the orientation of the metal effect pigments, which has in turn an influence on the sparkling effect and flop. In addition, in case such additional coloring pigments are present besides the metal effect pigment(s), the color appearance of the multilayer coating systems is often not sufficient, e.g., as far as color change values and chromaticity are concerned.
Thus, there is a need to provide colored and metal effect(s) containing coating compositions such as colored silvermetallic coating compositions, which are suitable to be used as basecoat coating compositions, e.g., for construction of multilayer coating systems comprising at least one basecoat layer derived from said compositions, which in turn are suitable to be used in the automotive industry, wherein said coating compositions are not only able to significantly improve the LIDAR reflectivity at incident angles of 35° and higher, particularly at an angle of 60 °, but also to simultaneously at least preserve both the lightness flop and the sparkle, and which furthermore are able to preserve or even improve the color appearance, in particular to minimize the color change and the loss in chromaticity.
Problem
It has been therefore an objective underlying the present invention to provide colored and metal effect(s) containing coating compositions such as colored silver-metallic coating compositions, which are suitable to be used as basecoat coating compositions, e.g., for construction of multilayer coating systems comprising at least one basecoat layer derived from said compositions, which in turn are suitable to be used in the automotive industry, wherein said coating compositions are not only able to significantly improve the LIDAR reflectivity at incident angles of 35° and higher, particularly at an angle of 60 °, but also to simultaneously at least preserve both the lightness flop and the sparkle, and which furthermore are able, due to the additional presence of coloring pigments in the coating compositions used, to additionally preserve or even improve the color appearance, in particular to minimize the color change and the loss in chromaticity. Solution
This objective has been solved by the subject-matter of the claims of the present application as well as by the preferred embodiments thereof disclosed in this specification, i.e. by the subject matter described herein.
A first subject-matter of the present invention is a coating composition comprising at least constituents a1), a3), a4), a5), and a6), and optionally further constituent a2), which are different from one another, namely as constituent a1) at least one film-forming polymer, as optional constituent a2) at least one crosslinking agent, if constituent a1) needs to be crosslinked externally, as constituent a3) at least one type of metal effect pigment, preferably at least two types of metal effect pigments, as constituent a4) at least one type of titanium dioxide pigment having a median particle size Dv50 in a range of from 275 to 1190 nm, preferably of from 325 to 1190 nm, as constituent a5) at least one type of non-black coloring pigment in an amount of at least 0.015 wt.-%, based on the total weight of the coating composition, and as constituent a6) water and/or one or more organic solvents.
A further subject-matter of the present invention is a method of coating of an optionally pre-coated substrate comprising at least a step A) and optionally also a step B), namely
A) applying the coating composition according to the present invention as defined hereinbefore and hereinafter, preferably as basecoat composition, at least in portion onto at least one optionally pre-coated surface of at least one substrate to form a coating film at least in portion on said surface, and
B) optionally curing or drying the coating film obtained after step A) to give a cured or dried coating layer.
A further subject-matter of the present invention is a multilayer coating system being present on an optionally precoated substrate and comprising at least two coatings layers L2 and L3 and optionally at least one of layers L1 and L2a, each being different from one another, namely optionally a first coating layer L1 applied over at least a portion of an optionally pre-coated substrate, said layer L1 being preferably obtainable from a first coating composition, which preferably is a primer coating composition, a second coating layer L2 applied over the first coating layer L1 , if present, or over at least a portion of a surface of the optionally pre-coated substrate, said layer L2 being obtainable from the coating composition according to the present invention as defined hereinbefore and hereinafter as a second coating composition or from the coating composition applied in step A) according to the method according to the present invention as defined hereinbefore and hereinafter, optionally a further coating layer L2a applied over the second coating layer L2, said optional layer L2a being obtainable from a basecoat composition, which is different from the coating composition according to the present invention, and a third coating layer L3 applied over the second coating layer L2 or, if present, over the coating layer L2a, said layer L3 being obtainable from a clearcoat composition as a third coating composition, wherein the multilayer coating system preferably has a LIDAR reflectivity, measured at an angle of incidence of 60°, of at least 5%.
Preferably, at least one of layers L2 or layer L2a is present and the multilayer coating system hence comprises at least three coating layers, namely L2, L3, and one of L1 and L2a. More preferably, either layer L1 or layer L2a is present and the multilayer coating system hence comprises at least three coating layers, namely L1 , L2, and L3, or L2, L2a and L3.
A further subject-matter of the present invention is a method of preparing a multilayer coating system onto an optionally pre-coated substrate, preferably of the multilayer coating system according to the present invention as defined hereinbefore and hereinafter, comprising at least steps 2), and 3), and optionally 1) and/or 2a) and/or 4), namely
1) optionally applying a first coating composition to an optionally pre-coated substrate and forming a first coating film on the optionally pre-coated substrate, wherein the first coating composition preferably is a primer coating composition,
2) applying a second coating composition to the first coating film obtained after step 1), if present, or to the optionally pre-coated substrate, preferably prior or to or after curing the first coating film if present, and forming a second coating film adjacent to the first coating film if present, or to at least part of the surface of the optionally pre-coated substrate as such, wherein the second coating composition is a coating composition according to the present invention as defined hereinbefore and hereinafter,
2a) optionally applying a further coating composition to the second coating film present on the substrate obtained after step 2), preferably prior or to or after curing the second coating film, and forming a further coating film adjacent to the second coating film, wherein the further coating composition preferably is a basecoat composition, and wherein it is different from the coating composition according to the present invention as defined hereinbefore and hereinafter,
3) applying a third coating composition to the second coating film present on the substrate obtained after step 2) or, if present, to the further coating film obtained after step 2a), preferably prior to curing the second and, if present, the further coating film, and forming a third coating film adjacent to the second coating film or if the present to the further coating film, and
4) optionally jointly curing at least the second and third coating films, optionally also the further coating film, and optionally also the first coating film, the cured third coating film being the outermost layer of the formed multilayer coating system, to obtain a multilayer coating system comprising cured first, if present, second, further, if present, and third coating layers.
A further subject-matter of the present invention is a coated substrate being obtainable by the method of coating of an optionally pre-coated substrate according to the present invention as defined hereinbefore and hereinafter or by the method of preparing a multilayer coating system onto an optionally pre-coated substrate according to the present invention as defined hereinbefore and hereinafter.
A further subject-matter of the present invention is a method of improving the LIDAR reflectivity and/or LIDAR detectability of objects, the method comprising the steps as defined in connection with the method of coating of an optionally pre-coated substrate according to the present invention as defined hereinbefore and hereinafter or with the method of preparing a multilayer coating system onto an optionally pre-coated substrate according to the present invention as defined hereinbefore and hereinafter, wherein the substrate is the object or becomes part of the object, which is to be improved in view of LIDAR reflectivity and/or LIDAR detectability.
A further subject-matter of the present invention is a use of the coated substrate according to the present invention as defined hereinbefore and hereinafter and/or of the multilayer coating system according to the present invention as defined hereinbefore and hereinafter and/or of an object produced from said substrate and/or from said multilayer coating system in LIDAR visibility applications, in particular concerning vehicles and parts thereof.
It has been in particular found that the coating composition according to the present invention is suitable to be used as basecoat coating composition, e.g., for construction of multilayer coating systems comprising at least one basecoat layer derived from said composition, which in turn are suitable to be used in the automotive industry.
It has been further in particular surprisingly found that the coating composition according to the present invention is able to significantly improve the LIDAR reflectivity of multilayer coating systems comprising at least one basecoat layer derived from said coating composition at incident angles of 35° and higher, particularly at angles in a range of from 35° to 60° and particularly at an angle of 60°. In this regard it has been found that the multilayer coating system particularly still has a LIDAR reflectivity, measured at an angle of incidence of 60°, of at least 5%.
Moreover, It has been further in particular surprisingly found that the coating composition according to the present invention is able to simultaneously at least preserve both the lightness flop and the sparkle of multilayer coating systems comprising at least one basecoat layer derived from said coating composition, and is furthermore able, due to and in view of the additional presence of coloring pigments in the coating composition, to additionally preserve or even improve the color appearance of the multilayer coating systems comprising at least one basecoat layer derived from said coating composition, in particular to minimize the color change and the loss in chromaticity. It has been in particular found that this effect is achieved by the presence of the at least one type of titanium dioxide pigment being present as constituent a4), when used in combination and together with the at least one type of nonblack coloring pigment a5) and the at least one type of metal effect pigment a3). In this regard it has been found that the presence of constituent a4) increases the occurrence of scattering in the n-IR area that makes sure that there is always a part of the signal reflecting back to the LiDAR sensor and hence improves the LiDAR reflectance, but that at the same time flop, sparkle, and color appearance properties such as chromaticity and color change are not deteriorated.
Detailed description of the invention
The term "comprising” in the sense of the present invention, in connection for example with the coating composition according to the present invention, preferably has the meaning of "consisting of”. With regard, e.g., to the coating composition according to the present invention it is possible - in addition to all mandatory constituents present therein - for one or more of the further optional constituents identified hereinafter to be also included therein. All constituents may in each case be present in their preferred embodiments as identified below.
The proportions and amounts in wt.-% (% by weight) of any of the constituents given hereinafter, which are present in each of the coating composition add up to 100 wt.-%, based in each case on the total weight of the coating composition.
Coating composition
A first subject-matter of the present invention is a coating composition comprising at least constituents a1), a3), a4), a5), and a6), and optionally further constituent a2), which are different from one another.
The inventive coating composition can be a solvent-based coating composition (in the following also referred to as solvent-borne coating composition) or an aqueous coating composition (in the following also referred to as waterborne coating composition). Preferably the coating composition is an aqueous coating composition. More preferably, the main ingredient of constituent a6) is water.
The term "waterborne” or "aqueous” is understood preferably for the purposes of the present invention to mean that water is present as the main constituent of all solvents and/or diluents present in the aqueous coating composition. Preferably, water is present in an amount of at least 35 wt.-%, based on the total weight of the coating composition. An aqueous coating composition preferably includes a water fraction of at least 40 wt.-%, more preferably of at least 45 wt.-%, based in each case on the total weight of the coating composition. The fraction of organic solvent(s) is preferably < 20 wt.-%, more preferably in a range of from 0 to < 20 wt.-%, very preferably in a range of from 0.5 to 20 wt.-% or to 17.5 wt.-% or to 15 wt.-% or to 10 wt.-%, based in each case on the total weight of the coating composition.
Preferably, the coating composition is used as a one-pack solvent-borne or waterborne basecoat composition. The inventive coating composition is in particular not a primer, primer surfacer, sealer and clearcoat composition and is thus not to be used/applied as a primer, primer surfacer, sealer and clearcoat composition. It typically forms the basecoat layer, which is in direct contact with one or more clearcoat layers of a multilayer coating system.
Preferably, the coating composition is suitable to be used as a basecoat coating composition and hence suitable for producing a basecoat layer. The term "basecoat” is known in the art and, for example, defined in Rbmpp Lexikon, "Lacke und Druckfarben” ("Paints and "Printing Inks”), Georg Thieme Verlag, 1998, 10th edition, page 57. A basecoat is therefore in particular used in automotive coating and general industrial paint coloring in order to give a coloring and/or an optical effect by using the basecoat as an intermediate coating composition. Basecoat compositions are generally applied to a metal or plastic substrate, optionally pretreated and/or precoated with a primer and/or filler, sometimes in the case of plastic substrates it might also be applied directly on the plastic substrate, and in the case of metal substrates on an electrodeposition coating layer coated onto the metal substrate or on the metal substrate already bearing a primer and/or filler and/or electrodeposition coating, or to already existing coatings in case of refinish applications, which can also serve as substrates. In order to protect a basecoat layer in particular against environmental influences, at least one additional clearcoat layer is applied to it, i.e., on top of it.
Preferably, a coating layer obtained from the coating composition of the present invention is able to reflect NIR (herein also referred to as n-IR or as near-IR) light, preferably NIR light having a wavelength from 800 to 2500 nm.
As used herein, the term "near-IR” or "near-infrared radiation or light” or "NIR” refers to electromagnetic radiation in the near-infrared range of the electromagnetic spectrum. Such near-IR electromagnetic radiation may have a wavelength from 800 nm to 2500 nm, such as from 850 to 2000 nm or such as from 900 nm to 1600 nm. In particular, the NIR light used has a wavelength from 880 nm to 930 nm with 905 nm as center wavelength. The near-IR electromagnetic radiation source that may be used in the present invention to produce NIR light includes, without limitation, light emitting diodes (LEDs), laser diodes or any light source that can emit electromagnetic radiation having a wavelength from 800 nm to 2500 nm (in the near-IR range). The near-IR electromagnetic radiation source may be used in a LiDAR (Light Detection and Ranging) system. The LiDAR system may utilize lasers to generate electromagnetic radiation with a wavelength from 900 nm to 1600 nm.
Preferably, the inventive coating composition does not contain any further constituents that are fillers. Thus, the inventive coating composition is preferably filler-free. In case any constituents are contained in the coating composition, that are pigments and/or fillers other than a3), a4) and a5), these constituents preferably do not or preferably do substantially not absorb light. Herein, thickeners, i.e., thickening agents are not considered to be subsumed under the term "pigments and/or fillers.”
Preferably, the coating composition has a solids content, based on the total weight of the basecoat composition, which is in a range from 10.0 to 35.0 wt.-%, more preferably from 15 to 30 wt.-%, even more preferably from 17 to 28 wt.-%, most preferably from 19 to 26 wt.-% in particular from 20 to 24 wt.%. The determination of the solids content, i.e., the non-volatile content, is described in the ‘methods' section.
Constituent a1)
As constituent a1) at least one film-forming polymer is present. The film-forming polymer is used as film-forming binder.
For the purposes of the present invention, the term "film-forming” is preferably understood to be the non-volatile constituent of a coating composition, which is responsible for the film formation, excluding pigments and fillers. Preferably, at least one polymer of a1) is the main binder of the coating composition. As the main binder in the present invention, a binder constituent is preferably referred to, when there is no other binder constituent in the coating composition, which is present in a higher proportion based on the total weight of the coating composition.
The term "polymer" is known to the person skilled in the art and, for the purposes of the present invention, encompasses polyadducts and polymerizates as well as polycondensates. The term "polymer" includes both homopolymers and copolymers.
The at least one polymer used as constituent a1) may be physically drying, self-crosslinkable or externally crosslinkable. Suitable polymers which can be used as constituent a1) are, for example, described in EP 0 228003 A1, DE 44 38 504 A1 , EP 0 593 454 B1 , DE 199 48 004 A1, EP 0 787 159 B1 , DE 40 09 858 A1 , DE 44 37 535 A1 , WO 92/15405 A1 , and WO 2005/021168 A1. The at least one polymer used as constituent a1) is preferably selected from the group consisting of polyurethanes, polyureas, polyesters, polyamides, poly(meth)acrylates and/or copolymers of the structural units of said polymers, and mixtures thereof, in particular polyurethane-poly(meth)acrylates and/or polyurethane polyureas. The at least one polymer used as constituent a1) is particularly preferably selected from the group consisting of polyurethanes, polyesters, poly(meth)acrylates and/or copolymers of the structural units of said polymers, and mixtures thereof. The term "(meth) acryl" or "(meth) acrylate" in the context of the present invention in each case comprises the meanings "methacrylic" and/or "acrylic" or "methacrylate" and/or "acrylate".
Preferred polyurethanes are described, for example, in German patent application DE 199 48 004 A1 , page 4, line 19 to page 11 , line 29 (polyurethane prepolymer B1), in European patent application EP 0 228 003 A1 , page 3, line 24 to page 5, Line 40, European Patent Application EP 0 634 431 A1 , page 3, line 38 to page 8, line 9, and international patent application WO 92/15405, page 2, line 35 to page 10, line 32. Preferred polyesters are described, for example, in DE 4009858 A1 in column 6, line 53 to column 7, line 61 and column 10, line 24 to column 13, line 3 or WO 2014/033135 A2, page 2, line 24 to page 7, line 10 and page 28, line 13 to page 29, line 13 described. Likewise, polyesters may have a dendritic structure, as described, for example, in WO 2008/148555 A1. Preferred polyurethane-poly(meth)acrylate copolymers (e.g., (meth)acrylated polyurethanes)) and their preparation are described, for example, in WO 91/15528 A1 , page 3, line 21 to page 20, line 33 and in DE 4437535 A1 , page 2, line 27 to page 6, line 22 described. Preferred poly(meth) acrylates are those which can be prepared by multistage free-radical emulsion polymerization of olefinically unsaturated monomers in water and/or organic solvents. For example, seed-core-shell polymers (SOS polymers) are particularly preferred. Such polymers or aqueous dispersions containing such polymers are known, for example, from WO 2016/116299 A1. Preferred polyurethane-polyurea copolymers are polyurethane-polyurea particles, preferably those having an average particle size of 40 to 2000 nm, the polyurethane-polyurea particles, each in reacted form, containing at least one isocyanate group-containing polyurethane prepolymer containing anionic and/or groups which can be converted into anionic groups and at least one polyamine containing two primary amino groups and one or two secondary amino groups. Preferably, such copolymers are used in the form of an aqueous dispersion. Such polymers can in principle be prepared by conventional polyaddition of, for example, polyisocyanates with polyols and polyamines.
The polymer used as constituent a1) preferably has reactive functional groups which enable a crosslinking reaction. Any common crosslinkable reactive functional group known to those skilled in the art can be present. Preferably, the polymer used as constituent a1) has at least one kind of functional reactive groups selected from the group consisting of primary amino groups, secondary amino groups, hydroxyl groups, thiol groups, carboxyl groups and carbamate groups. Preferably, the polymer used as constituent a1) has hydroxy functional groups. Preferably, the polymer used as constituent a1) is hydroxy-functional and more preferably has an OH number in the range of 10 to 500 mg KOH/g, more preferably from 40 to 200 mg KOH/g.
The polymer used as constituent a1) is particularly preferably a hydroxy-functional polyurethane-poly (meth)acrylate copolymer, a hydroxy-functional polyester and/or a hydroxy-functional polyurethane-polyurea copolymer.
Optional constituent a2)
As optional constituent a2) at least one crosslinking agent is present, if constituent a1) needs to be crosslinked externally, e.g., is not a self-crosslinking constituent.
Suitable crosslinking agents are typical crosslinking agents known per se by a person skilled in the art. Preferably, the at least one crosslinking agent, if present as a2), is at least one aminoplast resin and/or at least one blocked and/or free, more preferably blocked polyisocyanate, and most preferably at least one aminoplast resin. Most preferred, in case of aqueous one-pack coating compositions is the presence of aminoplast resins. Among the aminoplast resins, melamine resins such as melamine-aldehyde resins including melamine-formaldehyde resins are particularly preferred.
Preferably, the melamine aldehyde resins, preferably the melamine formaldehyde resins, in each case bear at least one of imino groups, alkykol groups and etherified alkylol groups as functional groups, which are reactive towards the functional groups of polymer constituent a). Examples of alkylol groups are methylol groups.
Crosslinking agents are to be included among the film-forming non-volatile constituents of a coating composition, and therefore fall within the general definition of the "binder” as described hereinbefore.
Constituent a3)
As constituent a3) at least one type of metal effect pigment is present. Preferably, at least two types of metal effect pigments are present as constituents a3).
The term "metal effect pigment” is preferably used in accordance with EN ISO 18451-1 :2019 (Pigments, dyestuffs, and extenders - Terminology - Part 1). Metal effect pigments are defined as platelet-shaped pigments "consisting” of metal. In the present invention the term "consisting of metal” does not exclude surface modifications of the metal effect pigments such as the presence of additional oxide layers, as e.g., a silicon dioxide layer. The term "metal” as used in the term "metal effect pigments” includes metals and metal alloys, likewise. Metal effect pigments can be orientated in parallel and show metallic gloss due to light reflection at the flakes. Typical metals and alloys used in metal effect pigments are aluminum and its alloys. Most suitable and preferred are platelet-shaped aluminum effect pigments, which might be coated or uncoated and which are preferably coated, particularly in case of the preferred aluminum pigments to inhibit their reaction with water in aqueous coating compositions. Such inhibition can, e.g., be achieved using organo-phosphorous stabilization, passivating the aluminum pigments with a conversion layer, e.g., by chromating, or encapsulation with a protective layer, such as a polymer coating or a silica coating (Peter Willing, "Metallic Effect Pigments”, Vincentz Network 2006, pp. 85-89). Such aluminum effect pigments are e.g., commercially available from ECKART GmbH (Germany) under the tradenames STAPA® Hydroxal (stabilized), STAPA® Hydrolux (chromated) and STAPA® Hydrolan (silica encapsulated). Further modification of the pigment surfaces is also possible, e.g., by modification with non-polar groups, such as alkyl groups leading to a so-called semi-leafing effect.
The metal effect pigments, particularly aluminum effect pigments, may be coated with an oxide layer, such as a silica layer and/or a chromium (III) and/or ferric oxide layer, which further helps to stabilize the pigments against mechanical impact und particularly improves circulation line stability. Preferably, oxide encapsulated aluminum metal effect pigments are used. Preferably, the amount of the oxide layer, based on the sum of the amounts of aluminum and oxide layer in such preferred aluminum effect pigments ranges from 3 to 15 wt.-% more preferred from 5 to 12 wt.-%, and most preferred from 6 to 10 wt.-%, each based on the total weight of the pigment. However, the term "metal effect pigment” encompasses such coated pigments and the total weight of such coated metal effect pigment is understood to be the weight of the metal effect pigment. Thus, the weight includes the coating material if present.
Preferably, the at least one type of metal effect pigment, which is present as constituent a3), is contained in the coating composition in an amount in a range of from 0.10 wt.-% to 10.00 wt.-%, more preferably of from 0.20 to 8.50 wt.-%, still more preferably of from 0.30 to 8.00 wt.-%, even more preferably of from 0.50 to 7.50 wt.-%, yet more preferably of from 0.75 to 5.00 wt.-%, most preferably of from 1 .00 to 4.50 wt.-%, in each case based on the total weight of the coating composition.
Preferably, based on the total amount of metal effect pigments a3), if more than one type of metal effect pigment is used, each of the two or more different metal effect pigments is present in an amount of at least 5 wt.-%, all amounts of metal effect pigments summing up to 100 wt.-%.
Preferably at least two types of metal effect pigments, more preferably aluminum effect pigments, are employed in the coating compositions of the present invention. It is clear that these at least two types of metal effect pigments are different from one another. As stated above, metal effect pigments such as aluminum effect pigments are preferably platelet-shaped. However, they may have different particle shapes and different particle size distributions and may be leafing or non-leafing metal effect pigments. Preferably, the at least one metal effect pigment is selected from non-leafing pigments, more preferably non-leafing aluminum effect pigments, which may have different shapes and/or different particle size distributions.
Preferably, the at least one type of metal effect pigment, which is present as constituent a3), has a platelet-thickness in the range from 80 nm to 1000 nm, more preferably of from 200 to 900 nm, even more preferably of from 300 to 800 nm. The platelet-thickness is determined according to the method disclosed in the ‘method section'. In general, the higher the platelet-thickness, the lower the LiDAR reflectance.
The shape of the metal effect pigment particles as employed in the present invention varies depends on the pigment manufacturing process. The shapes range from irregular formed platelets known as cornflake-shaped pigments to almost round platelets with minimal scattering proportions which are known as silver dollar-shaped pigments. Pictures and typical characteristics of both, cornflake-shaped and silver dollar shaped pigments are, e.g., shown in the textbook of Peter Willing, "Metallic Effect Pigments,” Vincentz Network 2006, pp. 31-33. It is preferred in the present invention that at least one type of metal effect pigment employed in the basecoat composition of the present invention is a cornflake-shaped metal effect pigment, preferably a cornflake-shaped aluminum effect pigment, and/or is a silver dollar-shaped metal effect pigment, preferably a silver dollar-shaped aluminum effect pigment. Typically, cornflake-shaped aluminum pigments show a higher LiDAR reflectance at incident angles in the range of 35° to 45°.
Preferably, the at least one type of metal effect pigment, which is present as constituent a3), is selected from aluminum effect pigments, more preferably from cornflake-shaped aluminum pigments and silver dollar-shaped aluminum pigments and mixtures thereof.
Beside the pigment shape the pigment particle size distribution is one characteristic of the at least one metal effect pigment to be used in the basecoat compositions of the present invention.
The particle size distribution is typically represented by the volume-based Dv10, Dv50 and Dv90 values of the pigment particles as determined with a Malvern Zetasizer as described in detail in the 'methods' section. Dv10 defines that the portion of particles with diameters smaller than this value is 10%. Dv50 defines that the portions of particles with diameters smaller this value are 50% and is also known as the median diameter. Dv90 defines that the portion of particles with diameters below this value is 90%. Preferably, the at least one type of metal effect pigment, which is present as constituent a3), has a Dv90 value of less than 60 m, more preferably of less than 50 pm, and/or has a Dv50 value of less than 40 pm, more preferably of less than 30 pm, and/or has a DV10 value of less than 25 pm, more preferably of ess than 20 pm. The particle size values Dv10, Dv50 and Dv90 are determined according to the method disclosed in the ‘method section'. In general, the higher the Dv50 value is the higher is the loss in LIDAR reflectance, particularly at incident angles in the range of 45°to 60°.
Preferably, at least two types of metal effect pigments are present as constituent a3), wherein more preferably the difference between the particle size distribution span of the metal effect pigment with the largest particle size distribution span and the metal effect pigment with the smallest particle size distribution span (PSDS) is in a range from 0.2 to 1.0, even more preferably in a range of 0.3 to 0.9, still more preferably in a range of 0.4 to 0.8, the particle size distribution span of each metal effect pigment being from the volume-based Dv90, Dv50 and DV10 values according to the following formula PSDS = [(Dv90-Dv10)/(Dv50)]. The larger the PSDS, the broader the particle size distribution.
The metal effect pigments are preferably employed in the coating compositions of the present invention in form of pigment pastes, wherein such pigment pastes preferably contain 40 to 70 wt.-%, more preferably 50 to 65 wt.-% of the metal effect pigments based on the total weight of the pastes. The volatile part is typically at least one organic solvent such as an alcohol. The pastes may further contain minor amounts of lubricants and other additives.
Constituent a4)
As constituent a4) at least one type of titanium dioxide pigment having a median particle size Dv50 in a range of from 275 to 1190 nm, preferably of from 325 to 1190 nm, is present. The median particle size Dv50 is determined according to the method disclosed in the ‘method section'.
The term "titanium dioxide pigment” as used herein preferably includes untreated titanium dioxide pigments as well as surface treated titanium dioxide pigments. Titanium dioxide pigments as used herein preferably comprise a titanium dioxide core, the surface of which is treated, i.e., modified with preferably one or more inorganic substances, preferably selected from one or more of oxides, hydroxides, oxide hydroxides, phosphates, and silicates of a metal and/or semi-metal, preferably the metal or semi-metal being one or more selected from silicon, aluminum, zirconium, and even titanium.
The titanium dioxide, which is contained in the titanium dioxide pigment a4) or of which the titanium dioxide pigments a4) consists, is preferably selected from the rutile type and anatase type, most preferred it is from the rutile type. To obtain inorganic surface modifications, the core titanium dioxide particles produced, e.g., in the sulfate processes (rutile and anatase) or chloride processes (only rutile), are preferably subjected to inorganic surface treatments. Preferably, the modification is accomplished by precipitating dissolved inorganic precursors onto the surface of the titanium dioxide core particles. Such precursors are, e.g., selected from NaAIC^, Al2(SO4)3, ZrOSO4 and TiOSC Metal halides are normally less appreciated as surface treatment chemicals due to their corrosiveness. By mixing basic and acidic precursor solutions, it is also possible to simultaneously precipitate two or more different inorganic substances onto the surface of the titanium dioxide particles, such as Al2(SO4)3 and Na2SiC>3, to form, for example, aluminum silicate. Such inorganic treatments typically increase weathering resistance and/or photostability.
A further treatment with organic substances is also possible. Such organic substances are preferably selected from organosilanes, fatty acids, polyalkyleneoxides and alkyl phosphates. Treatment with organic substances is typically accomplished to increase the dispersibility of the titanium pigments in the coating composition.
Preferably, constituent a4) is selected from titanium dioxide pigments, which are uncoated or coated with one or more oxides.
Preferably, the amount of titanium dioxide in the titanium dioxide pigment used as a4) is at least 85 wt.-%, more preferred at least 88 wt.-%, even more preferred at least 90 wt.-% and most preferred at least 92 wt.-%, up to 100 wt.-%, based on the total weight of the titanium dioxide pigment, the difference to 100 wt.-% being organic and/or inorganic substances, preferably present on the surface of titanium dioxide core particles. The organic substances preferably being selected from the above group of organic substances and the inorganic substances preferably being selected from one or more of oxides, hydroxides, oxide hydroxides, phosphates, and silicates of a metal or semi-metal, the metal or semi-metal preferably being selected from silicon, aluminum, zirconium, and titanium. Most preferred the inorganic substances are selected from the oxides, hydroxides and/or oxide hydroxides of silicon, aluminum, zirconium, and/or titanium.
The combined amounts of organic substances are preferably in the range from 0 to 3 wt.-%, more preferred 0 to 2 wt.-% and most preferred 0 to 1 wt.-%, based on the total weight of the titanium dioxide particles. The combined amounts of inorganic substances are preferably in the range of 0 to 12 wt.-%, more preferred 1 to 10 wt.-%, even more preferred 1 .5 to 9 wt.-%, most preferred 2 to 8 wt.-%, based on the total weight of the titanium dioxide particles.
Preferably, the at least one type of titanium dioxide pigment, which is present as constituent a4), is contained in the coating composition in an amount in a range of from 0.50 wt.-% to 5.00 wt.-%, more preferably of from 0.55 to 4.50 wt.-%, still more preferably of from 0.60 to 4.00 wt.-%, even more preferably of from 0.65 to 3.50 wt.-%, yet more preferably of from 0.70 to 3.00 wt.-%, in each case based on the total weight of the coating composition. Preferably, the at least one type of titanium dioxide pigment, which is present as constituent a4), has a median particle size Dv50 in a range of from 300 to 1150 nm including a range of from 325 to 1190 nm, more preferably of from 325 to 1100 nm, even more preferably of from 350 to 1050 nm.
Constituent a5)
As constituent a5) at least one type of non-black coloring pigment in an amount of at least 0.015 wt.-%, based on the total weight of the coating composition, is present. Preferably, constituent a5) is used for tinting purposes.
Preferably, the at least one non-black coloring organic pigment has a volume average particle size (Dv50) in the range of from 10 nm to <950 nm, preferably of from 25 nm to 900 nm, more preferably of from 30 nm to 850 nm, in particular of from 40 nm to <800 nm. Volume average particle size (Dv50) is determined by DLS according to the method described in the ‘methods' section hereinafter.
Preferably, the at least one type of non-black coloring pigment, which is present as constituent a5), is contained therein in an amount of at least 0.020 wt.-%, more preferably of at least 0.050 wt.-%, still more preferably of at least 0.075 wt.-%, even more preferably of at least 0.100 wt.-%, yet more preferably of at least 0.125 wt.-%, in each case based on the total weight of the coating composition.
Preferably, the at least one type of non-black coloring pigment, which is present as constituent a5), is contained therein in an amount of 0.015 to 20.0 wt.-%, more preferably of from 0.020 to 15.0 wt.-%, still more preferably of from 0.050 to 10.0 wt.-%, even more preferably of from 0.050 to 7.5 wt.-%, still more preferably of from 0.075 to 5.0 wt.-%, most preferably of from 0.100 to 4.5 wt.-%.
Preferably, at least two types of non-black coloring pigments are present in the coating composition as 5), which are different from one another.
Preferably, the at least one type of non-black coloring pigment is selected from organic and inorganic pigments, and mixtures thereof, more preferably from organic pigments.
Preferably, the at least one type of non-black coloring pigment, which is present as constituent a5), is selected from colored LiDAR transparent types of pigments. The term "LiDAR transparent” in the sense of the present invention in this context preferably is synonymously used with the term "NIR transparent”. Colored LiDAR transparent types of pigments, which are suitable for use as non-black coloring pigment constituent a5), are preferably organic pigments. Inorganic pigments for use as non-black coloring pigments being present as constituent a5) are preferably selected from LiDAR transparent pigments, LiDAR reflective pigments, and mixtures thereof. The term "LiDAR reflective” in the sense of the present invention in this context preferably is synonymously used with the term "NIR reflective”. Most preferably, however, at least one preferably organic LIDAR transparent is present as at least one type of non-black coloring pigment constituent a5).
Preferably, the at least one type of non-black coloring pigment, which is present as constituent a5), is selected from green, blue, turquoise, yellow, orange, red, violet, and brown pigments, and mixtures thereof, more preferably selected from green, blue, turquoise, yellow, orange, red, and violet, pigments, and mixtures thereof.
Preferably, the at least one type of non-black coloring pigment is selected from organic pigments such as perylenes, in particular as red pigments, quinacridones, azo pigments, diketopyrrolopyrroles (DPP), dioxazines, in particular as violet pigments, isoindolines, isoindolidones, and phthalocyanines and/or indanthrenes, in particular as blue and/or green and/or turquoise pigments, and mixtures thereof.
Constituent a6)
As constituent a6) water and/or one or more organic solvents is present. Constituent a6) is present in the coating composition in an amount, which is the difference between the weight of the total weight of the composition and its solids content.
When the inventive coating composition mainly comprises water as a volatile component, it is named an aqueous or waterborne composition. In this case it is preferably a coating composition comprising organic solvents in minor proportions.
All conventional organic solvents known to those skilled in the art can be used as organic solvents for the preparation of the coating composition of the invention. The term "organic solvent" is known to those skilled in the art, in particular from Council Directive 1999/13 / EC of 11 March 1999. Preferably, the one or more organic solvents are selected from the group consisting of monohydric or polyhydric alcohols, for example, methanol, ethanol, 1- propanol, 2-propanol, 1 -butanol, ethylene glycol, ethyl glycol, propyl glycol, butyl glycol, butyl diglycol, 1 ,2- propanediol and/or 1 ,3-propanediol; ethers, for example diethylene glycol dimethyl ether; aliphatic hydrocarbons, aromatic hydrocarbons, for example toluene and/or xylenes; ketones, for example acetone, N-methylpyrrolidone, N-ethylpyrrolidone, methyl isobutyl ketone, isophorone, cyclohexanone, methyl ethyl ketone; esters, for example methoxypropyl acetate, ethyl acetate and/or butyl acetate; amides, for example dimethylformamide and mixtures thereof.
Optional constituent a7)
Optionally, the coating composition further comprises at least one further type of pigment as constituent a7), which is different from each of pigment constituents a3), a4) and a5), wherein said at least one further type of pigment constituent a7) is selected from carbon black pigments. Preferably, said at least one further type of pigment being present as constituent a7) is contained in the coating composition in an amount of at most 0.50 or 0.30 or 0.10 wt.-%, more preferably of at most 0.09 wt.-%, even more preferably of at most 0.07 wt.-%, still more preferably of at most 0.05 wt.-%, most preferably of at most 0.03 wt.-%, in each case based on the total weight of the coating composition. Higher amounts are not preferred, since carbon blacks are LiDAR absorbing pigments, which lead to a decrease of LiDAR reflectance in the desired incident angle range.
Optional constituent a8)
Optionally, the coating composition further comprises at least one further type of pigment as constituent a8), which is different from each of pigment constituents a3), a4) and a5) and optionally present a7), wherein said at least one further type of pigment constituent a8) is selected from black LiDAR transparent pigments, black LiDAR reflective pigments, and mixtures thereof, more preferably from black LiDAR transparent pigments, even more preferably from organic black LiDAR transparent pigments, still more preferably from perylene and azomethine pigments and mixtures thereof. Constituent a8) may be used to partially or completely replace carbon blacks in the coating composition.
Suitable black coloring pigments, which preferably are LiDAR transparent pigments, are e.g., azomethine and/or perylene based pigments, as being available under the tradenames Spectrasense® Black L0086, formerly known as Paliogen® Black L0086, Spectrasense® Black K0087, formerly known as Lumogen® Black K0087, and Spectrasense® Black EH8082, while suitable black coloring pigments, which preferably are, LiDAR reflective pigments may be of a mixed metal oxide type and e.g., being available under the tradename Sicopal® Black L0095.
Most preferred are black pigments nos. 31 and 32 (P.B. 31 and P.B. 32), in particular P.B. 32 for use as constituent a8).
Preferably, said at least one further type of pigment being present as constituent a8) is contained in the coating composition in an amount of 0.010 to 4.0 wt.-%, more preferably of 0.020 to 3.0 or 2.5 wt.-%, even more preferred of 0.025 to 1 .5 wt.-% such as 0.030 to 1 .0 wt.-%, in each case based on the total weight of the coating composition.
Optional constituent a9)
Preferably, the coating composition further contains one or more further LiDAR transparent pigments, and/or one or more further LiDAR reflecting pigments, the latter one preferably having a masstone color with full hiding according to CIELAB system at 45° with a lightness value of L * >17 and/or being LiDAR reflecting platelet-shaped mica pigments. Pigment constituent a9) is different from each of pigment constituents a3), a4) and a5) and optionally present a7) and/or a8). LiDAR reflecting and/or LiDAR transparent further pigments to be used as constituent a9) can be contained as in amounts of preferably 0.01 to 4.0 wt.-%, more preferably 0.020 to 2.5 wt.-%, even more preferred in the range from 0.025 to 1 .5 wt.-% such as 0.030 to 1 wt.-% based on the total weight of the coating composition of the invention.
If further LiDAR reflecting pigments are present as a9), besides a4) and optionally present a8), it is preferred that these pigments are platelet-shaped pigments and/or pigments having a masstone color with full hiding according to Cl ELAB system at 45° with a lightness value of L * >17 or preferably L* >20.
As mica pigments, natural mica pigments as well as synthetic mica pigments can be used as constituent a9) as long as they are LiDAR reflecting. The term "synthetic mica” as used herein means "fluorinated mica” or "fluorine mica”, i.e. , a mica, wherein OH groups are replaced by F groups in the respective mica formula.
Synthetic fluorine containing micas can be synthesized as, e.g., described in US 2014/0251184 A1 or using the Bridgman-Stockbarger method making use of platinum crucibles with seeds. Particularly fluorphlogopite is a widely used pigment, having the formula KMg3AISi30ioF2. This fluorinated mica being the most important one in the present invention and being often used in cosmetic preparations. Amongst the fluorinated micas, particularly preferred fluorphlogopite is used, which is preferably covered or coated with titanium dioxide, iron oxide and/or treated with silanes. How to coat synthetic micas with e.g., titanium dioxide is, e.g., disclosed in EP 3 719 081 A1 , but also belongs to the state of the art since most mica products on the market are coated with metal oxides of different composition.
If contained, synthetic and natural mica pigments preferably contain titanium dioxide as a coating. However, small amounts of other oxides in the coating, such as iron oxide and the like are also suitable. Furthermore, some preferred grades may contain silanes as surface-modifiers in amounts of preferably 0 to 3 wt.-% based on the total weight of the pigment. Most preferred as mica pigments are synthetic or natural mica pigments, which are coated and/or surface-treated with one or more titanium oxide minerals. The titanium minerals are preferably selected from the group comprising titanium dioxides such as rutile, anatase and brookite; and iron titanium oxide minerals such as ilmenite. In the present invention it is preferred to use titanium oxide minerals with no or just low contents of iron, preferably not more than 10 wt.-%, even more preferred not more than 8 wt.-% and most preferred not more than 5 wt.-% of iron oxide based on the total pigment weight.
If synthetic or natural mica pigments are used, which comprise titanium oxide minerals, the weight of the mica content based on the total weight of the synthetic or natural mica pigment is preferably in the range from 55 to 90 wt.%, more preferred in the range from 60 to 85 wt.-% and most preferred 65 to 80 wt.-%, while the amount of titanium dioxide is preferably in the range from 10 to 45 wt.-%, more preferred 15 to 40 wt.-% and most preferred from 20 to 35 wt.-%. The term "synthetic or natural mica pigment” encompasses such coated and/or surface-treated pigments and the total weight of such coated and/or surface-treated mica pigments is understood to be the weight of the "synthetic or natural mica pigment”. Thus, the weight includes the coating material.
Commercially available platelet-shaped LIDAR reflecting mica pigments are e.g., available from Merck KGaA (Darmstadt, Germany) under the tradenames Iriotec® 9870, Iriotec® 9875 and Iriotec® 9880; Iriodin® 9612 SW Silver Grey Fine Satin and Iriodin® 9602 SW Silver Grey and Iriodin® 9225 SQB Rutil Perlblau; or from SUN Chemical (DIG) under the tradenames Mearlin CFS Bright Silver 1303Z and Mearlin CFS Fine Pearl 1303V and Mearlin Ext. CFS Supergold 2303Z.
Preferably, the coating composition does not contain any pigments besides constituents a3), a4), a5), optionally present a7), optionally present a8) and optionally present a9).
Further optional constituents
The coating composition of the present invention may contain one or more commonly used additives depending on the desired application. For example, the coating composition may comprise at least one additive selected from the group consisting of reactive diluents, such as polypropylene diols, light stabilizers, antioxidants, deaerators, emulsifiers, slip additives, polymerization inhibitors, plasticizers, initiators for free-radical polymerizations, adhesion promoters, flow control agents, film-forming auxiliaries, sag control agents (SCAs), flame retardants, corrosion inhibitors, siccatives, stabilizing additves, and/or matting agents. They can be used in the known and customary proportions. Preferably, their content, based on the total weight of the coating composition according to the invention is 0.01 to 25 wt.-%, more preferably 0.05 to 20 wt.-%, particularly preferably 0.1 to 15 % by weight, most preferably from 0.1 to 10 % by weight, especially from 0.1 to 7 % by weight and most preferably from 0.1 to 5 % by weight.
Amongst the additives, the coating composition according to the invention may optionally contain at least one thickener or rheology agent. Examples of such thickeners are inorganic thickeners, for example metal silicates such as sheet silicates, and organic thickeners, for example poly (meth)acrylic acid thickeners and/or (meth)acrylic acid (meth)acrylate copolymer thickeners, polyurethane thickeners, and polymeric waxes. The metal silicate is preferably selected from the group of smectites. The smectites are particularly preferably selected from the group of montmorillonites and hectorites. In particular, the montmorillonites and hectorites are selected from the group consisting of aluminum-magnesium silicates and sodium-magnesium and sodium-magnesium fluorine-lithium phyllosilicates. These inorganic phyllosilicates are marketed, for example, under the trademark Laponite® Thickeners based on poly(meth) acrylic acid and (meth) acrylic acid (meth) acrylate copolymer thickeners are optionally crosslinked and or neutralized with a suitable base. Examples of such thickening agents are "Alkali Swellable Emulsions" (ASE), and hydrophobically modified variants thereof, the "Hydrophobically Modified Alkali Swellable Emulsions" (HASE). Preferably, these thickeners are anionic. Corresponding products such as Rheovis® AS 1130 are commercially available. Polyurethane based thickeners (e.g., polyurethane associative thickeners) are optionally crosslinked and/or neutralized with a suitable base. Corresponding products such as Rheovis® PU 1250 are commercially available. Examples of suitable polymeric waxes are optionally modified polymeric waxes based on ethylene-vinyl acetate copolymers. A corresponding product is commercially available, for example, under the name Aquatix® 8421 .
It at least one thickener is present in the coating composition according to the invention, it is preferably present in an amount of at most 10 % by weight, more preferably at most 8 % by weight, most preferably at most 4 % by weight, especially at most 2 % by weight. %, most preferably not more than 1 % by weight, based in each case on the total weight of the coating composition. The minimum amount of thickener is preferably in each case 0.1 % by weight, based on the total weight of the coating composition.
The preparation of the coating composition can be carried out using customary and known preparation and mixing methods and mixing units or using conventional dissolvers and/or stirrers.
Method of coating
A further subject-matter of the present invention is a method of coating of an optionally pre-coated substrate comprising at least a step A) and optionally also a step B).
All preferred embodiments described hereinbefore in connection with the inventive coating composition are also preferred embodiments of the inventive method of coating.
Substrate
Suitability as metallic substrates used in accordance with the invention are all substrates used customarily and known to the skilled person. The substrates used in accordance with the invention are preferably metallic substrates, more preferably selected from the group consisting of steel, preferably steel selected from the group consisting of bare steel, cold rolled steel (CRS), hot rolled steel, galvanized steel such as hot dip galvanized steel (HDG), alloy galvanized steel (such as, for example, Galvalume, Galvannealed or Galfan) and aluminized steel, aluminum, alloys thereof and magnesium, and also Zn/Mg alloys and Zn/Ni alloys. Particularly suitable substrates are parts of vehicle bodies or complete bodies of automobiles for production. Metal substrates are preferably pretreated and/or precoated, most preferably bearing a primer and/(or) an electrodeposition coating as pre-coating layers and/(or) a conversion coating layer as pre-treatment of the metal surface. Further, the substrate used can be glass or a textile substrate, in particular glass. If the substrate is a plastic (polymeric) substrate, it may also be a pre-coated substrate, which, e.g., bears a primer coating, but does not have to. If plastic (polymeric) substrates are used, preferably, thermoplastic polymers are used as such substrates. Suitable polymers are poly(meth)acrylates including polymethyl(meth)acrylates, polybutyl (meth)acrylates, polyethylene terephthalates, polybutylene terephthalates, polyvinylidene fluorides, polyvinyl chlorides, polyesters, including polycarbonates and polyvinyl acetate, polyamides, polyolefins such as polyethylene, polypropylene, polystyrene, and also polybutadiene, polyacrylonitrile, polyacetal, polyacrylonitrile-ethylene-propylene-diene- styrene copolymers (A-EPDM), ASA (acrylonitrile-styrene-acrylic ester copolymers) and ABS (acrylonitrile- butadiene-styrene copolymers), polyetherimides, phenolic resins, urea resins, melamine resins, alkyd resins, epoxy resins, polyurethanes, including TPU, polyetherketones, polyphenylene sulfides, polyethers, polyvinyl alcohols, and mixtures thereof. Polycarbonates and poly(meth)acrylates are especially preferred. The substrate can also be a composite substrate such as a fiber reinforced substrate containing e.g., glass fibers, carbon fibers or polymeric fibers such as polyamide fibers. The substrate can also consist of multiple polymeric layers.
The substrate can have any shape and thickness, including the possibility that the substrate is a foil, sheet or film.
Step A)
In step A) the coating composition according to the present invention as defined hereinbefore and hereinafter is applied, preferably as basecoat composition, at least in portion onto at least one optionally pre-coated surface of at least one substrate to form a coating film at least in portion on said surface.
Preferably, the substrate is a pre-coated substrate, which is at least already coated with a primer layer, more preferably with a light-grey colored or white or dark such as black primer layer, even more preferably with a lightgrey colored or white primer layer. If the substrate is pre-coated with a primer coating layer, the primer coating is preferably light-colored, such as light-grey colored or white. Preferably the primer coating compositions and thus the primer coating or primer coating layer contains as main pigment titanium dioxide. Generally, the primer coating compositions and thus primer coating layers do not contain metal effect pigments. The term "main” pigment means that no other pigment in the primer coating compositions is contained in a higher amount than the main pigment.
Step B)
In optional step B) the coating film obtained after step A) is subjected to curing or drying to give a cured or dried coating layer.
Curing is preferably selected from chemical curing such as chemical crosslinking and/or radiation curing, whereas drying is preferably selected from physically drying (non-chemical curing), in each case at room temperature or at an elevated temperature. When the inventive coating composition is a - preferably aqueous - coating composition, step A) or steps A) and B) is/are preferably carried out onto at least one surface of a pre-coated substrate. If the substrate is a metal substrate, said metal substrate then preferably bears a primer and/(or) an electrodeposition coating as pre-coating layers and/(or) a conversion coating layer as pre-treatment layer underneath.
Independently of the substrate used, after having performed step A) or steps A) and B) preferably a clearcoat composition is applied directly onto the basecoat applied in a further step C) to form a clearcoat layer. The clearcoat can be cured separately or simultaneously with the basecoat layer or simultaneously with the primer layer and basecoat layer.
Coated substrate
A further subject-matter of the present invention is a coated substrate being obtainable by the method of coating of an optionally pre-coated substrate according to the present invention as defined hereinbefore and hereinafter.
All preferred embodiments described hereinbefore in connection with the inventive coating composition and the inventive method of coating are also preferred embodiments of the inventive coated substrate.
The coated substrate is preferably able to reflect near-infrared (NIR) light having a wavelength from 700 to 1700 nm.
The coated substrates can be used to produce, e.g., automotive bodies and parts thereof.
Multilayer coating system
A further subject-matter of the present invention is a multilayer coating system being present on an optionally precoated substrate and comprising at least two coatings layers L2 and L3 and optionally at least one of layers L1 and L2a, each being different from one another. Preferably, at least the second and the third coating layers L2 and L3 are positioned adjacently to each other, at least in case no optional layer L2a is further present. More preferably, also the first and the second coating layers L1 , if present, and L2 are positioned adjacently to each other. Likewise, preferably layers L2 and L2a, if present, are also positioned adjacently to each other.
Preferably, either layer L1 or layer L2a is present and the multilayer coating system hence comprises at least three coating layers, namely L2, L3, and one of L1 and L2a. All preferred embodiments described hereinbefore in connection with the inventive coating composition, the inventive method of coating, and the inventive coated substrate are also preferred embodiments of the inventive multilayer coating system.
Optional layer L1
The optionally present first coating layer L1 is applied over at least a portion of an optionally pre-coated substrate, said layer L1 being preferably obtainable from a first coating composition, which preferably is a primer coating composition. Preferably, the first coating layer L1 , if present, is a primer coating layer such as a light-grey colored or white primer layer. Preferably, layer L1 has a dry layer thickness in a range of from 25 to 40 pm, more preferably of from 30 to 35 pm.
The term "primer” or "primer coating composition” is known to a person skilled in the art. A primer typically is applied after the substrate has been provided with a cured electrodeposition coating layer. The cured electrodeposition coating film is present underneath and preferably adjacent to the cured primer coating film. Thus, a primer coating composition can be applied to an optionally pre-coated substrate and forming a primer coating film on the optionally pre-coated substrate. Then, an optional curing step of this primer coating film is possible before any further coating compositions are applied. The primer coating composition can be aqueous (waterborne) or organic solvent(s) based (solventborne, non-aqueous). The primer coating composition is free or essentially free of any metal effect pigments, in particular free or essentially free of any aluminum pigments.
Layer L2
The second coating layer L2 is applied over the first coating layer L1 , if present, or over at least a portion of the optionally pre-coated substrate, said layer L2 being obtainable from the coating composition according to the present invention as defined hereinbefore and hereinafter as a second coating composition or from the coating composition applied in step A) according to the method according to the present invention as defined hereinbefore and hereinafter. Preferably, the second coating layer L2 is a basecoat coating layer. Preferably, layer L2 has a dry layer thickness in a range of from 10 to 20 pm, more preferably of from 12 to 18 pm.
Optionally present Layer 2a
Optionally, a further layer L2a is present. The further layer L2a is preferably applied over the second coating layer L2. Preferably, further layer L2a is obtainable form a basecoat coating composition, which is, however, different from the inventive coating composition, and which preferably comprises at least one film-forming polymer being identical to or different from constituent a1 ). The basecoat coating composition, which is different from the inventive coating composition, and which is used for obtaining optionally present layer L2a, is preferably a transparent basecoat coating composition, which more preferably does not comprise any carbon black pigments and/or any aluminum effect pigments. Preferably, the further coating layer L2a is also a basecoat coating layer. Preferably, optionally present layer L2a has a dry layer thickness in a range of from 5 to 20 m, more preferably of from 7 to 15 pm.
Layer L3
The third coating layer L3 is applied over the second coating layer L2 or, if present, over the coating layer L2a, said layer L3 being obtainable from a clearcoat composition as a third coating composition. Hence, third coating layer L3 is a clearcoat coating layer such as a matt clearcoat layer.
Preferably, the third coating layer L3 is formed from solventborne clearcoat composition. Preferably, the third coating layer L3 is the outermost coating layer of the multilayer coating system.
Preferably, the multilayer coating system has a LiDAR reflectivity, measured at an angle of incidence of 60°, of at least 5%.
The multilayer coating system is preferably able to reflect near-infrared (NIR) light having a wavelength from 700 to 1700 nm.
The inventive coating composition (used for preparing L2), as well as the primer composition (used for preparing L1), and the further coating composition (used for preparing layer L2a) and/or clearcoat composition (used for preparing L3), can be coated onto a substrate by numerous techniques well-known in the art, including spray coating, drop coating, dip coating, roll coating, curtain coating, and other techniques. Preferably, the inventive coating compositions are applied by spray coating, more preferred by pneumatic or electrostatic spray coating. It can be applied wet-on-wet, but does not have to.
Preferably, the multilayer coating system is obtainable by a method, according to which at least the basecoat composition, which is used for preparing the second coating layer L2, and the coating composition used for preparing the third coating layer L3, which preferably is a clearcoat composition, are jointly cured to obtain the second and third coating layers L2 and L3 of the multilayer coating system. Preferably, said basecoat composition is applied onto the already cured first coating layer L1 , if present. Alternatively, the multilayer coating system may also be obtainable by a 3C1 B-method, wherein all coating compositions used to form coating layers L1 , if present, L2 and L3 are applied wet-on-wet-on-wet.
Alternatively and also preferably, the multilayer coating system is obtainable by a method, according to which at least the basecoat composition, which is used for preparing the second coating layer L2, and the coating composition used for preparing the third coating layer L3, which preferably is a clearcoat composition, are jointly cured to obtain the second and third coating layers L2 and L3 of the multilayer coating system. Preferably, said basecoat composition is applied or over at least a portion of the optionally pre-coated substrate. A further coating composition, preferably also being a basecoat composition, but which is different from the coating composition according to the present invention, is applied over the second coating layer L2 as layer L2, preferably prior to curing layer L2. The resulting multilayer coating system is hence be obtainable by a 3C1 B-method, wherein all coating compositions used to form coating layers L2, L2a and L3 are applied wet-on-wet-on-wet.
Method of preparing a multilayer coating system
A further subject-matter of the present invention is a method of preparing a multilayer coating system onto an optionally pre-coated substrate, preferably of the multilayer coating system according to the present invention as defined hereinbefore and hereinafter, comprising at least steps 2), 3), optionally 1) and/or optionally 2a) and/or optionally 4).
All preferred embodiments described hereinbefore in connection with the inventive coating composition, the inventive method of coating, the inventive coated substrate, and the inventive multilayer coating system are also preferred embodiments of the inventive method of preparing the multilayer coating system.
Optional step 1)
In optional step 1) a first coating composition is applied to an optionally pre-coated substrate and a first coating film is formed on the optionally pre-coated substrate, wherein the first coating composition preferably is a primer coating composition.
Step 2)
In step 2) a second coating composition is applied to the first coating film present on the substrate obtained after step 1), if present, or over at least a portion of the optionally pre-coated substrate, preferably prior or to or after curing the first coating film if present, and a second coating film is formed adjacent to the first coating film if present or to at least part of the surface of the optionally pre-coated substrate as such, wherein the second coating composition is a coating composition according to the present invention as defined hereinbefore and hereinafter.
Optional step 2a)
In optional step 2a) a further coating composition is applied to the second coating film present on the substrate obtained after step 2), preferably prior or to or after curing the second coating film, and a further coating film is formed adjacent to the second coating film, wherein the further coating composition preferably is a basecoat composition, which is different from the coating composition according to the present invention as defined hereinbefore and hereinafter. Step 3)
In step 3) a third coating composition is applied to the second coating film present on the substrate obtained after step 2) or to the further coating film obtained after step 2a), preferably prior to curing the second coating film and, if present, the further coating film, and a third coating film is formed adjacent to the second coating film or to the further coating film.
Step 4)
In optional step 4) at least the second, also the optionally present further, and third coating films and optionally also the first coating film are jointly cured, the cured third coating film being the outermost layer of the formed multilayer coating system, in order to obtain a multilayer coating system comprising cured first, if present, second, further, if present, and third coating layers.
Coated substrate (coated with a multilayer coating system)
A further subject-matter of the present invention is a coated substrate being obtainable by the method of preparing a multilayer coating system onto an optionally pre-coated substrate according to the present invention as defined hereinbefore and hereinafter.
All preferred embodiments described hereinbefore in connection with the inventive coating composition, the inventive method of coating, the inventive coated substrate, the inventive multilayer coating system, and the inventive method of preparing the multilayer coating system are also preferred embodiments of the inventive coated substrate coated with said multilayer coating system.
The coated substrate is preferably able to reflect near-infrared (NIR) light having a wavelength from 700 to 1700 nm.
The coated substrates can be used to produce, e.g., automotive bodies and parts thereof.
Method for improving the LIDAR reflectivity and/or LIDAR detectability of objects
A further subject-matter of the present invention is a method of improving the LiDAR reflectivity and/or LiDAR detectability of objects, the method comprising the steps as defined in connection with the method of coating of an optionally pre-coated substrate according to the present invention as defined hereinbefore and hereinafter or with the method of preparing a multilayer coating system onto an optionally pre-coated substrate according to the present invention as defined hereinbefore and hereinafter, wherein the substrate is the object or becomes part of the object, which is to be improved in view of LiDAR reflectivity and/or LiDAR detectability. All preferred embodiments described hereinbefore in connection with the inventive coating composition, the inventive method of coating, the inventive coated substrate, the inventive multilayer coating system, the inventive method of preparing the multilayer coating system, and the inventive coated substrate coated with said multilayer coating system are also preferred embodiments of the inventive method for improving the LiDAR reflectivity and/or LiDAR detectability of objects.
Use in LiDAR visibility applications concerning vehicles and parts thereof
A further subject-matter of the present invention is a use of the coated substrate according to the present invention as defined hereinbefore and hereinafter and/or of the multilayer coating system according to the present invention as defined hereinbefore and hereinafter and/or of an object produced from said substrate and/or from said multilayer coating system in LiDAR visibility applications, in particular concerning vehicles and parts thereof.
All preferred embodiments described hereinbefore in connection with the inventive coating composition, the inventive method of coating, the inventive coated substrate, the inventive multilayer coating system, the inventive method of preparing the multilayer coating system, the inventive coated substrate coated with said multilayer coating system, and the inventive method for improving the LiDAR reflectivity and/or LiDAR detectability of objects are also preferred embodiments of the aforementioned inventive use.
METHODS
1. Solids Content
The solids content (non-volatile fraction) was determined by drying approximately 1 g of the respective sample at a temperature of 125 °C for 60 min according to DIN EN ISO 3251 :2018-07, whereby the solid content resembles the residual amount of the respective sample in percent by weight.
2. Volume-based DV10, Dv50 and Dv90 values
The volume-based DV10, Dv50 and Dv90 values for pigments were determined by dynamic light scattering (DLS) (using of a Malvern Zetasizer from Malvern, S90 unit, Nanoseries Model ZEN 1690 mfg 5/2017). To carry out the measurements, the pigments and pigment pastes were diluted with appropriate solvent(s) (deionized water for aqueous dispersion and organic solvent(s) for solvent-based dispersion) not to exceed a photon count rate of approx. 300 to 500 counts when the unit was placed on an attenuator setting of 7. The operation temperature was held a 25 ± 1 °C and the sample size is approx. 10 to 15 mL (square glass cuvette).
3. Platelet thickness
The platelet-thickness was determined as follows: First, the flake pigment was dispersed in appropriate solvent and incorporated in a basecoat composition. Then, a basecoat composition containing the platelet-shaped pigment was sprayed on a substrate and cured. The thus obtained film was peeled off from the edge of the sample and small pieces of films were cut by microtome using a diamond knife and thin sections were transferred onto TEM grids. Thin sections were examined on STEM or TEM to determine the thickness of the respective flake pigment.
4. LIDAR reflectivity
The angle-dependent LIDAR reflectivity of the samples was measured with a Velodyne VLP-16 LIDAR sensor firing at 905 nm. The sensor was mounted at about 1 m from the samples and moved along a circular path around the sample center, so that the angle of incidence of the LIDAR radiation on the sheet was from 0° to 60°.
5. Sparkling Area
The sparkling effects were determined using a Byk-mac I device from Byk-Gardner GmbH (82538 Geretsried, Germany). This device allowed to measure sparkle. Accordingly, the sparkling behavior was characterized for the illumination angle of 15° by determination of the sparkling area (S_a) corresponding to the number of light reflections within the measurement given.
6. Flop Index
The flop index was calculated according the following formula: Flop wherein L* values was measured using the BYK-mac I instrument from Byk Gardner.
7. Hiding power
A checkerboard-like contrast sticker was brought lengthwise onto a rectangular 200 mm x 500 mm coil panel. One side was masked with three masking tapes, e.g. Tesa Krepp sticker: The first and the second sticker were brought directly onto the coil panel before the application. The second one was released after basecoat application to allow for clearcoat application directly on the coil panel. The first one was released after both basecoat and clearcoat application to receive an unpainted coil part. The third sticker was applied after basecoat application and released after clearcoat application to receive basecoat without clearcoat. This was performed to allow for later magnetic- inductive film thickness measurement. The panel was sprayed in electrostatic application in a wedge so that the black and white monitor was no longer be visible at the highest layer thickness. The basecoat was then flashed off 10 min at 80 °C and the full build up was dried for 20 min at 140 °C in the oven. It had to be assured that no dirt was present in the paint film. From the higher film side onwards while covering the thinner side with a paper, the film was regarded when the monitor started to be visible. The thickness, where the contrast sticker was visible for the first time under a lamp, was marked and measured magnetic-inductively.
8. Color change and chroma
The color change was determined using a Byk-mac I device from Byk-Gardner GmbH (82538 Geretsried, Germany). This device allowed to measure lightness L*, hue H*, red/green axis a*, yellow/blue axis b*, and chroma C* at a fixed illumination angle at 45° measured relative to the surface normal of the coating and at five different viewing angles (15° 125° 145° 1 75° 1 110°), each measured relative to the specular angle. Comparing it with a set standard (target), the differences in lightness (dL*; dl_*= L*1 - L*0, where L*0 = lightness of the standard and L*1 = lightness of the sample), hue (dH*), red/green deviation (da*; da*= a*1 - a*0, where a*0 = red/green axis values of the standard and a*1 = red/green axis values of the sample), yellow/blue deviation (db*; db*= b*1 - b*0, where b*0 = blue/yelllow axis values of the standard and b*1 = blue/yellow axis values of the sample), and chroma (dC*; dC*= C*1 - C*0, where C*0 = chroma of the standard and C*1 = chroma of the sample) were calculated. The color difference (color change) between the two colors, i.e., between the sample color and the target color, is specified dE* = - /dL *2 +do *2 +id& *2 as dE* ( ). EXAMPLES
The following examples further illustrate the invention but are not to be construed as limiting its scope. 'Pbw' means parts by weight. If not defined otherwise, ‘parts' means ‘parts by weight'.
1. Primer coating compositions
Two primer coating compositions have been prepared, one "white primer” (primer P1) and one "grey primer” (primer P2). The formulations are disclosed in Table 1.
2. Basecoat coating compositions
A number of basecoat coating compositions have been prepared. The formulations are disclosed in Tables 2a, 2b, 2c and 2d.
In Table 2a compositions 01 , 02, 03 and 0-0 are disclosed. Each of the compositions had an overall orange color. Composition 0-0 is a comparative composition. Further, in Table 2a compositions G1 , G2 and C-G are disclosed. Each of the compositions had an overall grey color. Composition C-G is a comparative composition. In Table 2b compositions GR1 and GR2 are disclosed. Each of the compositions had an overall green color. In Table 2c compositions B1 , B2 and C-B are disclosed. Each of the compositions had an overall blue color. Composition C-B is a comparative composition. Further, in Table 2c compositions G01 , G02, G03 and C-GO are disclosed. Each of the compositions had an overall golden color. Composition C-GO is a comparative composition. In Table 2d compositions SR1 , SR2, SR3, 01 -SR, C2-SR and C3-SR are disclosed. Each of the compositions had an overall blue/turquoise color. Compositions 01 -SR, C2-SR and C3-SR are comparative compositions.
21131 WO01 / L024857PCT 32 July 22, 2025 ASF Coatings GmbH able 1 - Primer coating compositions
21131 WO01 / L024857PCT 33 July 22, 2025 ASF Coatings GmbH
21131 WO01 / L024857PCT 34 July 22, 2025 ASF Coatings GmbH able 2a - Basecoat coating compositions
21131 WO01 / L024857PCT 35 July 22, 2025ASF Coatings GmbH l effect pigment 1 has the following particle size characteristics: Dv10 = 9 m, Dv50 = 15 pm, Dv90 = 24 pm.l effect pigment 2 has the following particle size characteristics: Dv10 = 12 pm, Dv50 = 21 pm, Dv90 = 32 pm.l-oxide effect pigment 1 has the following particle size characteristics: Dv10 = 9 pm, Dv50 = 18 pm, Dv90 = 31 pm. ica effect pigment 1 has the following particle size characteristics: Dv10 = 11 pm, Dv50 = 19 pm, Dv90 = 35 pm. ica effect pigment 2 has the following particle size characteristics: Dv10 = 11 pm, Dv50 = 22 pm, Dv90 = 40 pm.
21131 WO01 / L024857PCT 36 July 22, 2025 ASF Coatings GmbH able 2b - Basecoat coating compositions
21131 WO01 / L024857PCT 37 July 22, 2025ASF Coatings GmbH l effect pigment 3 has the following particle size characteristics: DV10 = 9 m, Dv50 = 20 pm, Dv90 = 32 pm.l effect pigment 4 has the following particle size characteristics: Dv10 = 14 pm, Dv50 = 24 pm, Dv90 = 36 pm.ica effect pigment 3 has the following particle size characteristics: Dv10 = 11 pm, Dv50 = 18 pm, Dv90 = 33 pm.
21131 WO01 / L024857PCT 38 July 22, 2025 ASF Coatings GmbH able 2c - Basecoat coating compositions
21131 WO01 / L024857PCT 39 July 22, 2025ASF Coatings GmbH l effect pigment 5 has the following particle size characteristics: Dv10 = 7 m, Dv50 = 17 pm, Dv90 = 29 pm.
21131 WO01 / L024857PCT 40 July 22, 2025 ASF Coatings GmbH able 2d - Basecoat coating compositions
21131 WO01 / L024857PCT 41 July 22, 2025ASF Coatings GmbH l effect pigment 6 has the following particle size characteristics: Dv10 = 10 pm, Dv50 = 18 pm, Dv90 = 28 pm.
3. Clearcoat coating composition
A clearcoat coating composition CC has been prepared. The formulation is disclosed in Table 3.
Table 3 - Clearcoat coating composition CC
4. Preparation of multilayer coating systems
A cold-rolled steel (CRS) panel bearing a zinc phosphate layer and precoated with a cathodic electrodeposition coating composition (CathoGuard® 800) was spray-coated by ESTA with the white (P1) or grey (P2) primer coating composition, composed as specified in Table 1. The thus obtained primer layer was cured for 20 minutes at 160 °C. It had a dry layer thickness of about 30 to 35 pm.
Onto the primer layer one of the basecoat coating compositions, composed as described in Tables 2a to 2d, was applied by spray-coating. After a flash-off for 10 min at 80 °C the thus obtained basecoat layers had a dry layer thickness of about 15 to 18 pm.
Onto the basecoat layers, the clearcoat composition CC (composed as described in Table 3) was applied by spraycoating ESTA. The thus obtained clearcoat layer was cured for 20 minutes together with the basecoat layer underneath at 140 °C. The clearcoat layer had a dry layer thickness of about 40 pm. 5. Investigation of properties of the multilayer coating systems
5.1 Some properties of the obtained multilayer coating systems have been investigated by the aforementioned methods described in the ‘methods' section. Hereinafter, "nd” means "not determined”. "LiDAR” means "LiDAR reflectivity measured at different incident angles”.
5.2 Some multilayer coating systems obtained by having made use of one of basecoat compositions 01, 02, 03 and 0-0 have been investigated with respect to their LiDAR reflectivity, flop, sparkling, chroma (dC at an angle of 15 °), color change (md_E’), and hiding power. The results are summarized in Table 5a hereinafter.
As it is evident from Table 5a a multilayer coating system comprising a basecoat layer obtained from one of basecoat compositions 01, 02, and 03 containing an inventively used TO2 pigment shows an excellent LiDAR reflectance, in particular at high incidence angles such as >5% at an angle of 60 °, which is not the case for a multilayer coating system comprising a basecoat layer obtained from basecoat compositions 0-0 not containing any TO2 pigment.
Table 5a
5.3 Some multilayer coating systems obtained by having made use of one of basecoat compositions G1 , G2, and C-G have been investigated with respect to their LiDAR reflectivity, flop, sparkling, chroma, color change, and hiding power. The results are summarized in Table 5b hereinafter. As it is evident from Table 5b a multilayer coating system comprising a basecoat layer obtained from one of basecoat compositions G1 , and G2 containing an inventively used TiO2 pigment shows an excellent LiDAR reflectance, in particular at high incidence angles such as >5% at an angle of 60 °, which is not the case for a multilayer coating system comprising a basecoat layer obtained from basecoat compositions C-G not containing any TO2 pigment. Table 5b
5.4 Some multilayer coating systems obtained by having made use of one of basecoat compositions GR1, and GR2 have been investigated with respect to their LiDAR reflectivity, flop, sparkling, chroma, color change, and hiding power. The results are summarized in Table 5c hereinafter.
Table 5c
As it is evident from Table 5c a multilayer coating system comprising a basecoat layer obtained from one of basecoat compositions GR1 and GR2 containing an inventively used TiO2 pigment shows an excellent LiDAR reflectance, in particular at high incidence angles such as >5% at an angle of 60 °.
5.5 Some multilayer coating systems obtained by having made use of one of basecoat compositions B1 , B2, and C-B have been investigated with respect to their LiDAR reflectivity, flop, sparkling, chroma, color change, and hiding power. The results are summarized in Table 5d hereinafter. Table 5d
As it is evident from Table 5d a multilayer coating system comprising a basecoat layer obtained from one of basecoat compositions B1 , and B2 containing an inventively used TiC>2 pigment shows an excellent LiDAR reflectance, in particular at high incidence angles such as >5% at an angle of 60 °, which is not the case for a multilayer coating system comprising a basecoat layer obtained from basecoat compositions C-B containing a comparatively used TiC>2 pigment with a low Dv50 of only 40 nm.
5.6 Some multilayer coating systems obtained by having made use of one of basecoat compositions GO1 , GO2, GO3 and C-GO have been investigated with respect to their LiDAR reflectivity, flop, sparkling, chroma, color change, and hiding power. The results are summarized in Table 5e hereinafter. Table 5e
As it is evident from Table 5e a multilayer coating system comprising a basecoat layer obtained from one of basecoat compositions GO1 , GO2 and GO3 containing an inventively used TiO2 pigment shows an excellent LiDAR reflectance, in particular at high incidence angles such as >5% at an angle of 60 °, which is not the case for a multilayer coating system comprising a basecoat layer obtained from basecoat compositions C-GO not containing any TO2 pigment.
5.7 Some multilayer coating systems obtained by having made use of one of basecoat compositions SR1 , SR2, SR3, C1-SR, C2-SR and C3-SR have been investigated with respect to their LiDAR reflectivity, flop, sparkling, chroma, color change, and hiding power. The results are summarized in Table 5f hereinafter. Table 5f
As it is evident from Table 5f a multilayer coating system comprising a basecoat layer obtained from one of comparative basecoat compositions C1-SR and C2-SR containing a TiO2 pigment having a Dv50 of only 250 nm shows a similar LiDAR reflectance as a multilayer coating system comprising a basecoat layer obtained from one of basecoat compositions SR1 , SR2 and SR3 containing an inventively used TiC>2 pigment with a higher Dv50 value. However, the multilayer coating systems comprising a basecoat layer obtained from one of comparative basecoat compositions C1-SR and C2-SR have a significantly inferior coloristic appearance: for example, in case of SR3 a color change of an md_E' of 7.03 is observed, whereas in case of C2-SR a much higher md_E' of 13.59 was observed. Also the loss in chroma dC at 15° is significant (in case of SR3 -2,91 and in case of C2-SR at -9,73).

Claims

1. A coating composition comprising at least constituents a1), a3), a4), a5), and a6), and optionally further constituent a2), which are different from one another, namely as constituent a1) at least one film-forming polymer, as optional constituent a2) at least one crosslinking agent, if constituent a1) needs to be crosslinked externally, as constituent a3) at least two types of metal effect pigments, as constituent a4) at least one type of titanium dioxide pigment having a median particle size Dv50 in a range of from 325 to 1190 nm, as constituent a5) at least one type of non-black coloring pigment in an amount of at least 0.015 wt.-%, based on the total weight of the coating composition, and as constituent a6) water and/or one or more organic solvents.
2. The coating composition according to claim 1 , characterized in that the at least one type of titanium dioxide pigment, which is present as constituent a4), is contained therein in an amount in a range of from 0.50 wt.-% to 5.00 wt.-%, preferably of from 0.55 to 4.50 wt.-%, more preferably of from 0.60 to 4.00 wt.-%, even more preferably of from 0.65 to 3.50 wt.-%, still more preferably of from 0.70 to 3.00 wt.-%, in each case based on the total weight of the coating composition.
3. The coating composition according to claim 1 or 2, characterized in that the at least one type of titanium dioxide pigment, which is present as constituent a4), has a median particle size Dv50 in a range of from 325 to 1150 nm, preferably of from 325 to 1100 nm, more preferably of from 350 to 1050 nm.
4. The coating composition according to one or more of the preceding claims, characterized in that the at least two types of metal effect pigments, which are present as constituent a3), are contained therein in an amount in a range of from 0.10 wt.-% to 10.00 wt.-%, preferably of from 0.20 to 8.50 wt.-%, more preferably of from 0.30 to 8.00 wt.-%, even more preferably of from 0.50 to 7.50 wt.-%, still more preferably of from 0.75 to 5.00 wt.-%, most preferably of from 1 .00 to 4.50 wt.-%, in each case based on the total weight of the coating composition.
5. The coating composition according to one or more of the preceding claims, characterized in that the at least two types of metal effect pigments, which are present as constituent a3), are selected from aluminum effect pigments, preferably from cornflake-shaped aluminum pigments and silver doll ar-shaped aluminum pigments.
6. The coating composition according to one or more of the preceding claims, characterized in that the at least two types of metal effect pigments, which are present as constituent a3), (I) have a platelet-thickness in the range from 80 nm to 1000 nm, preferably of from 200 to 900 nm, more preferably of from 300 to 800 nm, and/or (II) have a Dv90 value of less than 60 m, preferably of less than 50 pm, and/or (ill) have a Dv50 value of less than 40 pm, preferably of less than 30 pm, and/or (iv) have a Dv10 value of less than 25 pm, preferably of ess than 20 pm.
7. The coating composition according to one or more of the preceding claims, characterized in that at least two types of metal effect pigments are present as constituent a3), wherein the difference between the particle size distribution span of the metal effect pigment with the largest particle size distribution span and the metal effect pigment with the smallest particle size distribution span is in a range from 0.2 to 1 .0, preferably in a range of 0.3 to 0.9, more preferably in a range of 0.4 to 0.8, the particle size distribution span of each metal effect pigment being from the volume-based Dv90, Dv50 and Dv10 values according to the following formula [(Dv90-Dv10)/(Dv50)].
8. The coating composition according to one or more of the preceding claims, characterized in that the at least one type of non-black coloring pigment, which is present as constituent a5), and which preferably is selected from colored LIDAR transparent pigments, is contained therein in an amount of at least 0.020 wt.-%, preferably of at least 0.050 wt.-%, more preferably of at least 0.075 wt.-%, even more preferably of at least 0.100 wt.-%, still more preferably of at least 0.125 wt.-%, in each case based on the total weight of the coating composition.
9. The coating composition according to one or more of the preceding claims, characterized in that the at least one type of non-black coloring pigment, which is present as constituent a5), is selected from green, blue, turquoise, yellow, orange, red, violet, and brown pigments, and mixtures thereof.
10. The coating composition according to one or more of the preceding claims, characterized in that it comprises at least one further type of pigment as constituent a7), which is different from each of pigment constituents a3), a4) and a5), wherein said at least one further type of pigment constituent a7) is selected from carbon black pigments, wherein said at least one further type of pigment being present as constituent a7) is preferably contained in the coating composition in an amount of at most 0.10 wt.-%, more preferably of at most 0.09 wt.-%, even more preferably of at most 0.07 wt.-%, still more preferably of at most 0.05 wt.-%, most preferably of at most 0.03 wt.-%, in each case based on the total weight of the coating composition, and/or in that it comprises at least one further type of pigment as constituent a8), which is different from each of pigment constituents a3), a4) and a5) and optionally present a7), wherein said at least one further type of pigment constituent a8) is selected from black LiDAR transparent pigments, black LiDAR reflective pigments, and mixtures thereof, preferably from black LiDAR transparent pigments, more preferably from organic black LiDAR transparent pigments, even more preferably from perylene and azomethine pigments and mixtures thereof black LiDAR transparent pigments, wherein said at least one further type of pigment being present as constituent a8) is preferably contained in the coating composition in an amount of 0.010 to 4.0 wt.-%, more preferably of 0.020 to 3.0 or 2.5 wt.-%, even more preferred of 0.025 to 1.5 wt.-% such as 0.030 to 1.0 wt.-%„ in each case based on the total weight of the coating composition.
11. A method of coating of an optionally pre-coated substrate comprising at least a step A) and optionally also a step B), namely
A) applying the coating composition according to one or more of claims 1 to 10, preferably as basecoat composition, at least in portion onto at least one optionally pre-coated surface of at least one substrate to form a coating film at least in portion on said surface, and
B) optionally curing or drying the coating film obtained after step A) to give a cured or dried coating layer.
12. A multilayer coating system being present on an optionally pre-coated substrate and comprising at least two coatings layers L2 and L3 and optionally at least one of layers L1 and L2a each being different from one another, namely optionally a first coating layer L1 applied over at least a portion of an optionally pre-coated substrate, said layer L1 being preferably obtainable from a first coating composition, which preferably is a primer coating composition, a second coating layer L2 applied over the first coating layer L1 , if present, or over at least a portion of the optionally pre-coated substrate, said layer L2 being obtainable from the coating composition according to one or more of claims 1 to 10 as a second coating composition or from the coating composition applied in step A) according to the method of claim 11 , optionally a further coating layer L2a applied over the second coating layer L2, said optional layer L2a being obtainable from a basecoat composition, which is different from the coating composition according to one or more of claims 1 to 10, and a third coating layer L3 applied over the second coating layer L2 or, if present, over the coating layer L2a, said layer L3 being obtainable from a clearcoat composition as a third coating composition, wherein the multilayer coating system preferably has a LIDAR reflectivity, measured at an angle of incidence of 60°, of at least 5%.
13. A method of preparing a multilayer coating system onto an optionally pre-coated substrate, preferably of the multilayer coating system according to claim 12, comprising at least steps 2) and 3), and optionally 1) and/or optionally 2a) and/or optionally 4), namely
1) optionally applying a first coating composition to an optionally pre-coated substrate and forming a first coating film on the optionally pre-coated substrate, wherein the first coating composition preferably is a primer coating composition,
2) applying a second coating composition to the first coating film, if present on the substrate obtained after step 1), or to the optionally pre-coated substrate, preferably prior to or after curing the first coating film if present, and forming a second coating film adjacent to the first coating film, if present, or to at least part of the surface of the optionally pre-coated substrate as such, wherein the second coating composition is a coating composition according to one or more of claims 1 to 10,
2a) optionally applying a further coating composition to the second coating film present on the substrate obtained after step 2), preferably prior or to or after curing the second coating film, and forming a further coating film adjacent to the second coating film, wherein the further coating composition is a basecoat composition, and wherein it is different from the coating composition according to one or more of claims 1 to 10,
3) applying a third coating composition to the second coating film present on the substrate obtained after step 2) or, if present, to the further coating film obtained after step 2a), preferably prior to curing the second coating and, if present, the further coating film, and forming a third coating film adjacent to the second coating film or if the present to the further coating film, and
4) optionally jointly curing at least the second and third coating films, optionally the further coating film, and optionally also the first coating film, if present, the cured third coating film being the outermost layer of the formed multilayer coating system, to obtain a multilayer coating system comprising cured optionally first, second, optionally further, and third coating layers.
14. A coated substrate being obtainable by the method according to claim 11 or claim 13.
15. A method of improving the LiDAR reflectivity and/or LiDAR detectability of objects, the method comprising the steps as defined in claim 11 or 13, wherein the substrate is the object or becomes part of the object, which is to be improved in view of LiDAR reflectivity and/or LiDAR detectability.
16. A use of the coated substrate according to claim 14 and/or of the multilayer coating system according to claim 12 and/or of an object produced from said substrate and/or from said multilayer coating system in LiDAR visibility applications, in particular concerning vehicles and parts thereof.
PCT/EP2025/070978 2024-07-23 2025-07-22 Lidar reflective colored coatings Pending WO2026022140A1 (en)

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EP24190282 2024-07-23

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