Multilayer coating system obtained from block copolymer containing a base coat composition

Abstract

The present invention relates to a multi-layer coating system present on a substrate and comprising at least three coating layers L1, L2 and L3 which are different from one another, namely a first pigmented coating layer L1 applied on at least a part of the substrate, a second coating layer L2 applied on the first pigmented coating layer L1 and a third coating layer L3 applied on the second coating layer L2, in which the second coating layer L2 is formed from a coating composition comprising at least one block copolymer containing a main chain and at least two blocks B1 and B2 and side chains S1 and S2 comprising different polymer moieties M1 and M2, a method for producing said multi-layer coating system, coated substrates obtainable therefrom and the use of the coating composition comprising a block copolymer for improving, in particular increasing, the chromaticity of the multi-layer coating system of the present invention.

Description

[Technical Field]

[0001] The present invention relates to a multilayer coating system comprising at least three distinct coating layers L1, L2, and L3 present on a substrate, namely a first pigment coating layer L1 applied on at least a portion of the substrate, a second coating layer L2 applied on the first pigment coating layer L1, and a third coating layer L3 applied on the second coating layer L2, wherein the second coating layer L2 is formed from a coating composition comprising at least one block copolymer containing a main chain and at least two blocks B1 and B2, and side chains S1 and S2 comprising different polymer portions M1 and M2; a method for producing the multilayer coating system; a coated substrate that can be obtained therefrom; and the use of a coating composition comprising a block copolymer to improve, in particular to increase, the chromaticity of the multilayer coating system of the present invention. [Background technology]

[0002] In a typical automotive coating method, a multilayer coating system is generally applied to the surface of a suitable substrate, such as a metal substrate, in the form of a multilayer coating system. For example, an electrodeposited coating (e-coat) as the outermost layer, optionally a primer, one or two base coats, and a topcoat, especially a clear coat, are applied in this order. At least an e-coat layer is generally applied to the substrate surface and then cured before any further coatings are applied on top. Following application and curing, at least an electrodeposited coating film and also optionally a primer are applied, followed by at least one (first) basecoat formulation, usually pigmented. Often, a second basecoat is applied on top of the first basecoat film as a further intermediate coating film. Then, a topcoat, such as a clear coat, is usually applied, and at least the basecoats and topcoats are typically applied using wet-on-wet application techniques. The coated substrate is then passed through an oven in a 2C1B or 3C1B method, depending on the number of basecoats, at a temperature that allows at least the basecoats and the topcoats, such as a clear coat, to cure simultaneously. In some cases, if present, the primer coat is also cured at this stage together with the base coat and top coat, especially the clear coat, for example in the 4C1B method.

[0003] There are a great many required conditions that must be met and / or met by multilayer coatings used in the automotive industry, which are due to regulations but also to quality standards set by the automotive industry as such. Therefore, multilayer coatings must exhibit or demonstrate several desirable properties to at least a sufficient degree in order to meet these requirements. For example, avoidance of optical defects is desirable. In addition, and especially, it is desirable that excellent color properties of the multilayer coating be achieved.

[0004] A multilayer coating comprising at least two coating layers is disclosed, for example, in WO2020 / 160299A1. The first layer is a photoquantum crystal film containing a dye and a block copolymer. A second layer, present on the first layer, is used as a topcoat and is an optical adhesive or a UV-curable resin. The block copolymer is always present in the first layer together with at least one dye. WO2020 / 160299A1 aims to provide a multilayer coating having good transparency in the visible spectrum. A coating composition used to produce a dyed photoquantum crystal film as such is further disclosed in WO2020 / 180427A1, but multilayer coatings are not disclosed there, much less multilayer coatings produced via wet-on-wet technology.

[0005] Since multilayer coatings known in the latest technology do not always exhibit sufficiently good color properties, for example, in terms of brightness, but especially in terms of chromaticity, there is a need to provide cured coatings and coating systems that exhibit improved color properties and color values, particularly in terms of chromaticity and the achievement of excellent saturation values, compared to coatings and coating systems known in the prior art. At the same time, these cured coatings and coating systems should be manufactured in an economically advantageous manner, especially in terms of the shortest possible processing time, including the shortest possible curing time, if they are to be used in automotive OEM production. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] WO2020 / 160299A1 [Patent Document 2] WO2020 / 180427A1 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] Thus, the object underlying the present invention is to exhibit improved color properties and color values compared to coatings and coating systems known in the prior art, particularly with respect to their chromaticity and the achievement of excellent color saturation values, and at the same time to be manufactured in an economically advantageous manner, particularly in terms of a processing time as short as possible, including a curing time as short as possible, especially when these multilayer coating systems are used in automotive OEM production.

Means for Solving the Problems

[0008] This object has been solved by the subject matter of the patent application scope of the present application and by those preferred embodiments thereof disclosed herein, i.e., by the subject matter described herein.

[0009] The first subject matter of the present invention is present on an optionally pre-coated substrate and comprises at least three coating layers L1, L2 and L3 which are different from each other, i.e., a first pigmented coating layer L1 applied on at least a part of the optionally pre-coated substrate, a second coating layer L2 applied on the first pigmented coating layer L1, and a third coating layer L3 applied on the second coating layer L2 in a multilayer coating system, characterized in that the second coating layer L2 is formed from a coating composition comprising a main chain and at least one block copolymer containing at least two blocks B1 and B2 which are different from each other. Block B1 includes at least one type of side chain S1 bonded to the main chain, block B2 includes at least one type of side chain S2 different from side chain S1 and bonded to the main chain, each of side chains S1 includes at least one polymer part M1 selected from the group consisting of parts of polyester, polyether and poly(meth)acrylate, each of side chains S2 is different from polymer part M1 and includes at least one polymer part M2 selected from the group consisting of parts of polyester, poly(meth)acrylate, polyether, polysiloxane and polystyrene. It is a multilayer coating system.

[0010] A further subject of the present invention is a method for manufacturing the multilayer coating system of the present invention, comprising at least steps (1), (2), (3) and (4), namely (1) applying a pigmented base coat composition to at least a part of an optionally pre-coated substrate to form a first coating film on at least a part of the optionally pre-coated substrate; (2) applying a second base coat composition containing at least one block copolymer, different from the base coat composition applied in step (1), to the first coating film present on the substrate obtained after step (1), preferably forming a second coating film adjacent to the first coating film; (3) applying a coating composition different from the compositions applied in steps (1) and (2) to the second coating film present on the substrate obtained after step (2), preferably forming a third coating film adjacent to the second coating film, wherein the coating composition is preferably a clear coat composition. (4) A step of curing together the at least second and third coating films applied in steps (2) and (3), and optionally the first coating film applied in step (1) if the first coating film was not cured before step (2), to obtain a multilayer coating system comprising at least first, second, and third coating layers L1, L2, and L3. This method includes [something].

[0011] A further subject of the present invention is a coated substrate that can be obtained by the method of the present invention.

[0012] A further subject of the present invention is to improve, and more preferably to improve, the chromaticity of, the multilayer coating system of the present invention, a coating composition comprising at least one block copolymer used in the present invention, particularly its C* 平均 A method for increasing the saturation value, wherein C* 平均 The saturation value is, in particular when the coating composition is used as a second base coat composition in step (2) of the method of the present invention, the sum of the C* values ​​(saturation values ​​according to the L*C*h color model) measured at angles of 15°, 45° and 110° divided by 3, and more preferably, to improve the C* 平均 A saturation value of at least 40, preferably at least 42, more preferably at least 45, even more preferably at least 50, even more preferably at least 55, and especially at least 60 C* 平均 This is a method used to increase the value.

[0013] The block copolymer used in the present invention will also be referred to as copolymer BBCP hereafter.

[0014] It has been found, particularly surprisingly, that the multilayer coating systems of the present invention exhibit improved color properties and color values, especially when compared to coatings and coating systems known in the prior art. This is especially true for the chromaticity and excellent saturation values ​​of these multilayer coating systems. In this regard, the chromaticity of multilayer coating systems can be improved, particularly, for example, their C* 平均 It was found that the saturation value can increase, and the aforementioned C* 平均 The saturation value is calculated by dividing the sum of the C* values ​​(saturation values ​​according to the L*C*h color model) measured at angles of 15°, 45°, and 110° by 3. 平均 C* has a saturation value of at least 40, preferably at least 42, more preferably at least 45, even more preferably at least 50, even more preferably at least 55, and especially at least 60. 平均 It was found that the value could rise.

[0015] Furthermore, it was found to be particularly surprising that multilayer coating systems, especially when these coatings and coating systems are used in automotive OEM production, can be produced in an economically advantageous manner in terms of short processing time and short curing time.

[0016] It has been found, in particular surprise, that the aforementioned advantageous effects are a result of the incorporation of the block copolymer BBCP into the coating composition and the use of the coating composition as a midcoat composition (second basecoat composition) when manufacturing the multilayer coating system of the present invention. It has been found, even more surprisingly, that these effects can be observed in an advantageous manner when a particular wet-on-wet coating is used to manufacture the multilayer coating system, and the applied coating composition containing at least one block copolymer BBCP used to manufacture the second coating layer L2 and the applied coating composition used to manufacture the third coating layer L3 are cured together, i.e., simultaneously, to obtain the second and third coating layers L2 and L3 of the multilayer coating system.

[0017] In particular, it was surprisingly found that the presence of a third coating layer L3 on top of coating layer L2 halts the desired color shift observed during curing; when coating layer L3 is not present on top of coating layer L2, i.e., when the coating composition used to produce coating layer L2 actually represents the topcoat as the outermost coat, a significant decrease in saturation is found to occur, which is undesirable. It was surprisingly found that applying the third coating layer L3 on top of coating layer L2, especially in a wet-on-wet application, where the coating composition used to produce the third layer L3 is applied before the coating composition containing at least one block copolymer BBCP used to produce coating layer L2 is cured, and the two resulting films are then cured together, which unexpectedly prevents this decrease in saturation. These results were observed for a variety of chemically different third coating layers L3, which is even more surprising. [Modes for carrying out the invention]

[0018] For example, in the method of the present invention, or in relation to the coating composition used to manufacture the multilayer coating system of the present invention, the term “contains” in the sense of the present invention preferably means “consisting of.” For example, in the case of a second base coat composition, in addition to all the essential components present therein, one or more further components, optionally specified and included therein, may also be included therein. All components may, in each case, be present in their preferred embodiments as specified below.

[0019] The proportion and wt.-% (mass%) of any of the components present in each coating composition, as described later in this specification, are in a total of 100 wt.% of the total mass of each composition.

[0020] Each of the coating compositions used in steps (1), (2), and (3) of the method of the present invention, and / or used to produce coating layers L1, L2, and L3, may contain, in addition to the components outlined in more detail later herein, one or more commonly used additives, depending on the desired application. For example, each of the coating compositions may independently contain at least one additive selected from the group consisting of reactive diluents, catalysts, light stabilizers, antioxidants, degassing agents, emulsifiers, lubrication additives, polymerization inhibitors, plasticizers, free radical polymerization initiators, adhesion promoters, flow regulators, film-forming aids, sagging modifiers (SCAs), flame retardants, corrosion inhibitors, drying agents, thickeners, biocides, and / or matting agents. They may be used in known and customary proportions. Preferably, their content relative to the total mass of each coating composition is 0.01 to 20.0 wt.-%, more preferably 0.05 to 15.0 wt.-%, particularly preferably 0.1 to 10.0 mass%, most preferably 0.1 to 7.5 mass%, particularly 0.1 to 5.0 mass%, and most preferably 0.1 to 2.5 mass%.

[0021] In the method of the present invention, in particular in each of steps (1) to (3), and / or each of the coating compositions used to produce the multilayer coating system, can be aqueous (water-based) or organic solvent-based (solvent-based, non-aqueous).

[0022] For the purposes of the present invention, the terms “solvent-based” or “non-aqueous” are preferably understood to mean that, when each coating composition is solvent-based, the organic solvent is present in each coating composition as a solvent and / or diluent, as a main component of all solvents and / or diluents present in the second base coat composition applied in step (2) of the method of the present invention. Preferably, the organic solvent is present in an amount of at least 35 wt.-% of the total mass of the coating composition. Solvent-based coating compositions preferably contain at least 40 wt.-%, more preferably at least 45 wt.-% and very preferably at least 50 wt.-% of the organic solvent fraction in each case, based on the total mass of the coating composition. All conventional organic solvents known to those skilled in the art can be used as organic solvents. The term “organic solvent” is known to those skilled in the art, in particular from Council Directive 1999 / 13 / EC of March 11, 1999. Examples of such organic solvents include heterocyclic, aliphatic, or aromatic hydrocarbons, monoalcohols, or polyhydric alcohols, particularly methanol and / or ethanol, ethers, esters, ketones, and amides, such as N-methylpyrrolidone, N-ethylpyrrolidone, dimethylformamide, toluene, xylene, butanol, ethyl glycol and butyl glycol and their acetates, butyl diglycol, diethylene glycol dimethyl ether, cyclohexanone, methyl ethyl ketone, methyl isobutyl ketone, acetone, isophorone, or mixtures thereof. The solvent-based coating composition is preferably water-free or essentially water-free. In this context, the term "essentially" preferably means that water is not intentionally added when manufacturing the coating composition.

[0023] The terms "aqueous" or "water-based" are preferably, for the purposes of the present invention, understood to mean that water is present as the main constituent of all solvents and / or diluents present in an aqueous coating composition, such as the first base coat composition applied in step (1) of the process of the present invention. Preferably, water is present in an amount of at least 35 wt.-% relative to the total mass of the coating composition. The aqueous coating composition preferably contains a water fraction of at least 40 wt.-%, more preferably at least 45 wt.-%, very preferably at least 50 wt.-%, in each case relative to the total mass of the coating composition. The fraction of organic solvents is preferably <20 wt.-%, more preferably in the range from 0 to <20 wt.-%, very preferably in the range from 0.5 to 20 wt.-%, or ~17.5 wt.-%, or ~15 wt.-%, or ~10 wt.-% in each case relative to the total mass of the coating composition.

[0024] The multilayer coating system of the present invention The multilayer coating system of the present invention is present on an optionally pre-coated substrate and comprises at least three coating layers L1, L2 and L3 which are different from one another.

[0025] Preferably, at least the second and third coating layers L2 and L3 are positioned adjacent to one another. More preferably, also the first and second coating layers L1 and L2 are positioned adjacent to one another.

[0026] Preferably, the multilayer coating system preferably has, after curing, at least 40, more preferably at least 42, even more preferably at least 45, still more preferably at least 50, still more preferably at least 55, especially at least 60 C* 平均 value, this C* 平均 value being the sum of the C* values (chroma values according to the L*C*h color model) measured at angles of 15°, 45° and 110° divided by 3. The method for measuring the chroma value is described later herein in the "Method" section.

[0027] Preferably, the multilayer coating system can be obtained by curing together at least an applied coating composition containing at least one block copolymer BBCP used to produce a second coating layer L2 and an applied coating composition used to produce a third coating layer L3 to obtain the second and third coating layers L2 and L3 of the multilayer coating system.

[0028] Curing is preferably selected from chemical curing, e.g., chemical crosslinking, irradiation curing and / or physical drying (non-chemical curing), at room temperature or with increased temperature in each case, and more preferably selected from chemical curing, e.g., chemical crosslinking and / or physical drying (non-chemical curing), at room temperature or with increased temperature in each case, and preferably the minimum curing temperature applied for curing is 80°C.

[0029] substrate The multilayer coating system of the present invention is particularly suitable as a coating for the body or parts of an automobile, including not only metal substrates but also plastic substrates such as polymer substrates. As a result, the preferred substrate is the body or parts of an automobile.

[0030] Suitable metal substrates for use in accordance with the present invention are all commonly used and known to those skilled in the art. Substrates used in accordance with the present invention are preferably metal substrates, more preferably metal substrates selected from the group consisting of steel, preferably untreated steel, cold-rolled steel (CRS), hot-rolled steel, galvanized steel, such as hot-dip galvanized steel (HDG), alloyed galvanized steel (e.g., galvalume, alloyed hot-dip galvanized, or galfan, etc.), and aluminum-plated steel, aluminum and magnesium, as well as steels selected from the group consisting of Zn / Mg alloys and Zn / Ni alloys. Particularly suitable substrates are production, automotive, body parts, or complete body parts.

[0031] Preferably, thermoplastic polymers are used as plastic substrates. Suitable polymers include poly(meth)acrylates, including polymethyl(meth)acrylate, polybutyl(meth)acrylate, polyethylene terephthalate, polybutylene terephthalate, polyvinylidene fluoride, polyvinyl chloride, polyesters, including polycarbonate and polyvinyl acetate, polyamides, polyolefins, such as polyethylene, polypropylene, polystyrene, and also polybutadiene, polyacrylonitrile, polyacetal, polyacrylonitrile-ethylene-propylene-diene-styrene copolymer (A-EPDM), ASA (acrylonitrile-styrene-acrylic ester copolymer) and ABS (acrylonitrile-butadiene-styrene copolymer), polyetherimide, phenolic resins, urea resins, melamine resins, alkyd resins, epoxy resins, polyurethanes, including TPU, polyetherketone, polyphenylene sulfide, polyether, polyvinyl alcohol, and mixtures thereof. Polycarbonate and poly(meth)acrylate are particularly preferred.

[0032] The substrates used in accordance with the present invention are preferably metal substrates pre-treated with at least one metal phosphate such as zinc phosphate, and / or metal substrates pre-treated with at least one oxalate. This type of pre-treatment by phosphate treatment, which is usually performed after the substrate has been cleaned and before the substrate is electrodeposited, is a pre-treatment process that is particularly common in the automotive industry.

[0033] As outlined above, the substrate used may be a pre-coated substrate, i.e., a substrate having at least one cured coating film. The substrate may be pre-coated with a cured electrodeposited coating layer. The substrate may, for example, be provided with at least one cured or uncured primer coating film as an additional pre-coat, either in addition or alternatively. The term “primer” is known to those skilled in the art. The primer is typically applied to the substrate after the cured electrodeposited coating layer has been provided. If a cured primer coating film is present, the cured electrodeposited coating film is located underneath and preferably adjacent to the cured primer coating film. Curing the primer may be carried out at a temperature in the range of 40 to 140°C, and may particularly include a “low firing” step at a temperature in the range of 80 to 100°C. As outlined above, a substrate having an uncured primer coating film, in particular a substrate such as a metal substrate having a cured electrodeposited coating film on which the uncured primer coating film is located, may be used. Therefore, the primer composition can be optionally applied to a pre-coated substrate to optionally form a primer coating film on the pre-coated substrate. Subsequently, an optional curing step of the primer coating film is possible. Then, the coating composition used to form the first coating layer L1 can be optionally, and preferably, applied after a flashing-off period, for example 1 to 20 minutes, before or after the curing of the primer coating film, at a temperature not exceeding 40°C, for example, in the range of 18 to 30°C.

[0034] Coating layer L1, and coating composition used to form the layer The first coating layer L1 is dyed and applied to at least a portion of an optionally pre-coated substrate. Therefore, the first coating layer L1 is present on at least a portion of the surface of the optionally pre-coated substrate.

[0035] Preferably, the first pigmented coating layer L1 is capable of absorbing at least wavelengths that are not reflected by the second layer L2.

[0036] The first coating layer L1 is preferably formed from a pigmented coating composition. This coating composition is also referred herein to as the first base coat composition or the first pigmented base coat composition, and is the composition used in step (1) of the method of the present invention.

[0037] The first base coat composition is preferably an aqueous, i.e., water-based coating composition or a solvent-based base coat composition. In particular, it is a solvent-based base coat composition. The first base coat composition may be a 1K-(one component) composition or a 2K-(two component) composition. Preferably, it is a 1K-composition.

[0038] The term "base coat" is well known in the art and is defined, for example, in Roempp Lexikon, *paints and printing inks*, Georg Thieme Verlag, 1998, 10th edition, page 57. Therefore, base coats are used, particularly in automotive painting and general industrial paint coloring, to provide coloring and / or optical effects by using a base coat as an intermediate coating composition.

[0039] Preferably, the first base coat composition comprises at least one white, black, and / or colored pigment, more preferably at least one black pigment, and specifically at least one inorganic and / or organic black pigment.

[0040] The term “pigment” is known to those skilled in the art, for example, from DIN 55943 (dated October 2001). In the sense of the present invention, “pigment” preferably refers to a component in powder or flake form, which is substantially, preferably completely, insoluble in the medium surrounding them, for example, one of the coating compositions used in the present invention. The pigment is preferably a colorant and / or substance that can be used as a pigment because of its magnetic, electrical and / or electromagnetic properties. The pigment is preferably different from the “filler” in its refractive index, the refractive index for the pigment is ≥1.7. The term “filler” is known to those skilled in the art, for example, from DIN 55943 (dated October 2001). The pigment may be inorganic or organic. Black pigments, especially organic and / or inorganic black pigments, are preferred.

[0041] If at least one organic black pigment is present in the first base coat composition, it is preferably at least one IR-permeable organic black pigment, particularly at least one perylene and / or azomethine pigment. Most preferably, the organic black pigments are black pigments 31 and 32 (PB31 and PB32). If at least one inorganic black pigment is present in the first base coat composition, it is preferably at least one carbon black pigment.

[0042] An aqueous or non-aqueous pigment paste containing at least one pigment is preferably used to produce the first base coat composition, depending on whether the first base coat composition is solvent-based or aqueous.

[0043] Preferably, at least one dye present in the first base coat composition is contained in an amount of 5 to 30 wt.-%, more preferably 6.0 to 25.0 wt.-%, even more preferably 7.5 to 20 wt.-%, and particularly 8.0 to 16 wt.-%, relative to the total solid content of the first base coat composition in each case.

[0044] Preferably, the total solid content of the first base coat composition is in the range of 10 to 65 wt.-%, more preferably 15 to 60 wt.-%, even more preferably 20 to 50 wt.-%, and particularly 25 to 45 wt.-%, based on the total mass of the first base coat composition in each case. A method for measuring the solid content (non-volatile content) is described later in this specification in the "Methods" section.

[0045] The first base coat composition preferably comprises, in addition to at least one dye, at least one binder, and more preferably at least one polymer (a1) as a binder.

[0046] For the purposes of this invention, the term “binder” is understood to mean a non-volatile component of the coating composition that influences film formation, in accordance with DIN EN ISO 4618 (German version, dated March 2007). The term includes crosslinking agents and additives when they refer to non-volatile components. Dyes and / or fillers contained therein are therefore not included in the term “binder.” Preferably, at least one polymer (a1) is the primary binder of the coating composition. As a primary binder in this invention, the binder component preferably refers to one that is present in a higher proportion of the total mass of the coating composition than other binder components present in the coating composition.

[0047] The term "polymer" is known to those skilled in the art and, for the purposes of this invention, includes polyadditives and polymers, as well as polycondensates. The term "polymer" includes both homopolymers and copolymers.

[0048] Preferably, the first base coat composition does not contain copolymer BBCP present in the coating composition used to form the coating layer L2. Therefore, preferably, the first base coat composition does not contain any polymers that are copolymer BBCP.

[0049] At least one polymer used as component (a1) may be self-crosslinkable or non-self-crosslinkable. Suitable polymers that can be used are known from, for example, EP0228003A1, DE4438504A1, EP0593454B1, DE19948004A1, EP0787159B1, DE4009858A1, DE4437535A1, WO92 / 15405A1 and WO2005 / 021168A1.

[0050] The at least one polymer used as component (a1) is preferably selected from the group consisting of polyurethane, polyurea, polyester, polyamide, polyether, poly(meth)acrylate, and / or copolymers of the structural units of the polymer, particularly polyurethane-poly(meth)acrylate and / or polyurethane-polyurea. The at least one polymer used as component (a1) is particularly preferably selected from the group consisting of polyurethane, polyester, poly(meth)acrylate, and / or copolymers of the structural units of the polymer. In the context of the present invention, the terms "(meth)acrylic" or "(meth)acrylate" include, in each case, the meanings of "methacrylic" and / or "acrylic," or "methacrylate" and / or "acrylate."

[0051] Preferred polyurethanes are described, for example, in German Patent Application DE19948004A1, pages 4, lines 19 to 11, lines 29 (polyurethane prepolymer B1), European Patent Application EP0228003A1, pages 3, lines 24 to 5, lines 40, European Patent Application EP0634431A1, pages 3, lines 38 to 8, lines 9, and International Patent Application WO92 / 15405, pages 2, lines 35 to 10, lines 32.

[0052] Preferred polyethers are described, for example, in WO2017 / 097642A1 and WO2017 / 121683A1.

[0053] Preferred polyesters are described, for example, in DE4009858A1, rows 6, 53 to 7, 61, and rows 10, 24 to 13, 3, or in WO2014 / 033135A2, pages 2, 24 to 7, 10, and pages 28, 13 to 29, 13. Similarly preferred polyesters are those having a dendritic or star-shaped structure, which are described, for example, in WO2008 / 148555A1.

[0054] Preferred polyurethane-poly(meth)acrylate copolymers (e.g., (meth)acrylated polyurethanes) and their manufacture are described, for example, on pages 3, lines 21 to 20, line 33 of WO91 / 15528A1, and on pages 2, lines 27 to 6, line 22 of DE4437535A1.

[0055] Preferred (meth)acrylic copolymers are OH-functional. Hydroxyl-containing monomers include hydroxyalkyl esters of acrylic or methacrylic acid that can be used to produce copolymers. Non-limiting examples of hydroxyl-functional monomers include hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, hydroxyhexyl (meth)acrylate, propylene glycol mono(meth)acrylate, 2,3-dihydroxypropyl (meth)acrylate, pentaerythritol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, polyethylene glycol mono(meth)acrylate, reaction products of these with epsilon-caprolactone, and other hydroxyalkyl (meth)acrylates having branched or linear alkyl groups of up to about 10 carbon atoms, as well as mixtures thereof. Hydroxyl groups on vinyl polymers, such as (meth)acrylic polymers, can be produced by other means, such as ring-opening of glycidyl groups, e.g., from polymerized glycidyl methacrylate, using organic acids or amines. Hydroxyl functionality can also be introduced through thio-alcohol compounds, including but not limited to 3-mercapto-1-propanol, 3-mercapto-2-butanol, 11-mercapto-1-undecanol, 1-mercapto-2-propanol, 2-mercaptoethanol, 6-mercapto-1-hexanol, 2-mercaptobenzyl alcohol, 3-mercapto-1,2-propanediol, 4-mercapto-1-butanol, and combinations thereof. Any of these methods can be used to produce useful hydroxyl-functionalized (meth)acrylic polymers.Examples of suitable comonomers that may be used include, but are not limited to, α,β-ethylenically unsaturated monocarboxylic acids containing 3 to 5 carbon atoms, such as acrylic acid, methacrylic acid, and crotonic acid, as well as alkyl and cycloalkyl esters, nitriles, and amides of acrylic acid, methacrylic acid, and crotonic acid; α,β-ethylenically unsaturated dicarboxylic acids and anhydrides containing 4 to 6 carbon atoms, monoesters and diesters of these acids; vinyl esters, vinyl ethers, vinyl ketones, and aromatic or heterocyclic aliphatic vinyl compounds. Typical examples of suitable esters of acrylic acid, methacrylic acid, and crotonic acid include these esters from the reaction with saturated aliphatic alcohols containing 1 to 20 carbon atoms, such as methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, tert-butyl, hexyl, 2-ethylhexyl, dodecyl, 3,3,5-trimethylhexyl, stearyl, lauryl, cyclohexyl, alkyl-substituted cyclohexyl, alkanol-substituted cyclohexyl, such as 2-tert-butyl and 4-tert-butylcyclohexyl, 4-cyclohexyl-1-butyl, 2-tert-butylcyclohexyl, 4-tert-butylcyclohexyl, 3,3,5,5-tetramethylcyclohexyl, tetrahydroglobulin Examples include, but are not limited to, furyl, isobornyl acrylate, isobornyl methacrylate, and isobornyl crotonic acid; unsaturated dialkanoates and anhydrides, such as fumaric acid, maleic acid, itaconic acid, and anhydrides, as well as alcohols, such as methanol, ethanol, propanol, isopropanol, butanol, isobutanol, and tert-butanol, and their mono- and diesters, such as maleic anhydride, dimethyl maleate, and monohexyl maleate; vinyl acetate, vinyl propionate, vinyl ethyl ether, and vinyl ethyl ketone; styrene, α-methylstyrene, vinyltoluene, 2-vinylpyrrolidone, and p-tert-butylstyrene. (Meth)acrylic copolymers can be produced using the prior art, for example, by heating monomers in the presence of polymerization initiators and optionally chain transfer agents.

[0056] Suitable poly(meth)acrylates can also be produced by multi-step free-radical emulsion polymerization of olefinic unsaturated monomers in water and / or organic solvents. Examples of seed-core-shell polymers (SCS polymers) obtained by this method are disclosed in WO2016 / 116299A1.

[0057] Preferred polyurethane-polyurea copolymers include polyurethane-polyurea particles, preferably having a Z-average particle size of 40 to 2000 nm; a polyurethane prepolymer containing at least one isocyanate group containing an anionic group and / or a group that can be converted to anionic groups; and polyurethane-polyurea particles in reacted forms containing at least one polyamine containing two primary amino groups and one or two secondary amino groups. Preferably, such copolymers are used in the form of aqueous dispersions. Such polymers can, in principle, be produced, for example, by conventional polyaddition of polyisocyanates with polyols and polyamines.

[0058] The polymer used as component (a1) preferably has a reactive functional group that enables a crosslinking reaction. Any common crosslinkable reactive functional group known to those skilled in the art may be present. Preferably, the polymer used as component (a1) has at least one type of functional reactive group selected from the group consisting of primary amino groups, secondary amino groups, hydroxyl groups, thiol groups, carboxyl groups, and carbamate groups. Preferably, the polymer used as component (a1) has a functional hydroxyl group and / or a carbamate group.

[0059] Preferably, the polymer used as component (a1) is hydroxyl functional and more preferably has an OH number in the range of 15 to 400 mg KOH / g, and more preferably 20 to 250 mg KOH / g.

[0060] The polymer used as component (a1) is particularly preferably a hydroxyl-functional polyurethane-poly(meth)acrylate copolymer, a hydroxyl-functional polyester, and / or a hydroxyl-functional polyurethane-polyurea copolymer.

[0061] In addition, the first base coat composition may contain at least one typical crosslinking agent that is known in itself. The crosslinking agent will be included in the film-forming non-volatile components of the coating composition and is therefore within the general definition of a “binder”. Thus, the crosslinking agent will be included in component (a1).

[0062] All conventional crosslinking agents can be used. These include melamine resins, preferably melamine aldehyde resins, more preferably melamine formaldehyde resins, blocked polyisocyanates, polyisocyanates having free (unblocked) isocyanate groups, crosslinking agents having amino groups such as secondary and / or primary amino groups, crosslinking agents having epoxide groups and / or hydrazide groups, and crosslinking agents having carbodiimide groups, insofar as the functional groups of the particular crosslinking agent are suitable for reacting with the crosslinkable functional groups of the film-forming polymer used as a binder in the crosslinking reaction. For example, crosslinking agents having blocked or free isocyanate groups can be reacted with film-forming polymers having crosslinkable OH groups and / or amino groups at elevated temperatures in the case of a 1K formulation, and at ambient temperature in the case of a 2K formulation.

[0063] If a crosslinking agent is present, it is preferably at least one aminoplast resin and / or at least one blocked or free polyisocyanate, preferably an aminoplast resin. Among the aminoplast resins, melamine resins, such as melamineformaldehyde resin, are particularly preferred. Preferably, the melamineformaldehyde resin, preferably melamineformaldehyde resin, has, in each case, at least one of an imino group, an alkylol group, and an etherified alkylol group as a functional group, which is reactive with the functional groups of polymer P1. An example of an alkylol group is a methylol group.

[0064] Coating layer L2, and coating composition used to form the layer The second coating layer L2 is applied on top of the first pigmented coating layer L1. Therefore, the second coating layer L2 is preferably located on top of the coating layer L1. The second coating layer L2 is formed from a coating composition comprising at least one block copolymer BBCP. This coating composition is also referred herein as the second base coat composition and is the composition used in step (2) of the method of the present invention.

[0065] The second base coat composition may be an aqueous, i.e., water-based coating composition. Alternatively, the second base coat composition may be a solvent-based base coat composition. In particular, it is, in fact, a solvent-based base coat composition. The base coat composition may be a 1K-(one-component) composition or a 2K-(two-component) composition. Preferably, it is a 1K-composition.

[0066] Preferably, the second base coat composition does not contain a dye. Preferably, the second base coat composition does not contain a filler, and most preferably, it does not contain both a dye and a filler. However, alternatively, a coating composition comprising at least one block copolymer BBCP is a pigmented coating composition.

[0067] Preferably, the second base coat composition is a solvent-based coating composition, which preferably does not contain a dye.

[0068] Preferably, the total solids content of the second base coat composition is in the range of 15 to 70 wt.-%, more preferably 20 to 65 wt.-%, even more preferably 25 to 60 wt.-%, and particularly 30 to 55 wt.-%, based on the total mass of the second base coat composition in each case. A method for measuring the solids content (non-volatile content) is described later in this specification in the "Methods" section.

[0069] The second base coat composition must include at least one block copolymer BBCP. As already outlined above, the block copolymers used in the present invention are also referred to as copolymer BBCP, both later and earlier herein.

[0070] Preferably, at least one copolymer BBCP is present in the coating composition used to produce the second coating layer L2 in an amount ranging from 10 to 100 wt.-%, more preferably 15 to 100 wt.-%, and even more preferably 20 to 95 wt.-%, relative to the total solid content of the coating composition in each case.

[0071] At least one type of block copolymer BBCP comprises a main chain and at least two distinct blocks B1 and B2. Block B1 comprises at least one type of side chain S1 bonded to the main chain, and block B2 comprises at least one type of side chain S2 bonded to the main chain, different from side chain S1. Each of the side chains S1 and S2 is bonded to the main chain of the copolymer BBCP used in the present invention, and the copolymer is a block copolymer comprising at least two blocks B1 and B2, where block B1 now comprises the aforementioned side chain S1, and block B2 now comprises the aforementioned side chain S2, so that at least a portion of the main chain of the copolymer used in the present invention to which side chain S1 is bonded is also a portion of block B1, and at least a portion of the main chain of the copolymer used in the present invention to which side chain S2 is bonded is also a portion of block B2. It is further evident that a portion of block B1 that does not constitute at least one type of side chain S1 but to which a side chain S1 is bound constitutes a portion of the copolymer's main chain, and a portion of block B2 that does not constitute at least one type of side chain S2 but to which a side chain S2 is bound also constitutes a portion of the copolymer's main chain. Each of the side chains S1 comprises at least one polymer portion M1 selected from the group consisting of polyester, polyether, and poly(meth)acrylate portions, and each of the side chains S2, unlike polymer portion M1, comprises at least one polymer portion M2 selected from the group consisting of polyester, poly(meth)acrylate, polyether, polysiloxane, and polystyrene portions. The side chains S1 and S2 are preferably covalently bonded to the main chain of the block copolymer BBCP. The main chain of the copolymer BBCP preferably contains an ethylenically unsaturated carbon-carbon double bond, but is not required to do so.

[0072] Copolymer BBCP can preferably be obtained by ring-opening metathesis polymerization (ROMP) using cyclic ethylenically unsaturated, preferably cyclic olefin monomers. ROMP is a specific olefin metathesis chain growth polymerization. The driving force of this reaction is the relaxation of ring strain in the cyclic olefin (e.g., norbornene monomer or cyclopentene monomer).

[0073] Preferably, the main chain of the copolymer BBCP comprises olefinic carbon-carbon double bonds, more preferably arranged in a regular and / or repeating pattern, and even more preferably such that each structural unit described later herein is covalently bonded to another structural unit via carbon-carbon double bonds. These double bonds are preferably formed between ROMPs. When the copolymer BBCP is obtained in this manner, i.e., by ROMPs, the formed carbon-carbon double bonds present in the main chain may subsequently be optionally hydrogenated to saturated carbon bonds, such as alkylene moieties.

[0074] Those skilled in the art will recognize methods for producing copolymers BBCP, particularly those produced via ROMP, and copolymers BBCP as such are publicly known, for example, disclosed in WO2020 / 160299A1, WO2020 / 180427A1, and BRSveinbjoernsson et al., PNAS2012, 109(36), pp. 14332-14336. The production of copolymers BBCP is also described in these references, and in the case of articles in cited journals, in the supporting information therein.

[0075] The block copolymer BBCP is preferably a linear block copolymer. The block copolymer BBCP preferably has a block-like sequence of copolymerized structural units at least partially derived from a suitable ethylenically unsaturated monomer, preferably a cyclic olefin. Preferably, (meth)acrylic monomers are not used to produce the block copolymer BBCP.

[0076] Block copolymers (BBCPs) comprise at least two blocks and are therefore at least diblock copolymers, more preferably linear diblock copolymers. However, copolymers (BBCPs) may also comprise additional blocks, such as triblock copolymers.

[0077] Block copolymers are copolymers obtained by adding at least two different ethylenically unsaturated monomers, two different mixtures of ethylenically unsaturated monomers, or by adding ethylenically unsaturated monomers and mixtures of ethylenically unsaturated monomers at different times in a controlled polymerization practice, where the ethylenically unsaturated monomers or mixtures of ethylenically unsaturated monomers are initially added at the start of the reaction. When further ethylenically unsaturated monomers or mixtures of ethylenically unsaturated monomers are added, or when ethylenically unsaturated monomers are added in multiple parts, the ethylenically unsaturated monomers added at the start of polymerization may already be completely reacted or still be partially polymerized. As a result of such polymerization, block copolymers may have at least one transition in their structural units along the polymer chain (polymer back chain), where the transition marks the boundaries between individual blocks. Preferred block copolymer structures are, for example, AB diblock copolymers, ABA triblock copolymers, or ABC triblock copolymers. Block copolymers more commonly used in the present invention contain blocks having a minimum of two structural units per block.

[0078] Preferably, the block copolymer BBCP is of type AB, ABA, BAB, ABC, and / or ACB, where block A, block B, and block C represent different compositions of structural units, blocks A, B, and C differ in their respective compositions of structural units, and / or the amounts of structural units in two adjacent blocks differ from each other by more than 5% by mass in each case. However, the most preferred is the AB diblock copolymer.

[0079] Preferably, at least one copolymer BBCP present in the second base coat composition is 450-300 0 Within the range, more preferably 500-250 0 Within the range, more preferably 550-200 0 Within the range, more preferably 600-150 0 Within the range, especially 650-100 0 Number-average molecular weight within the range (M n ) has.

[0080] Number average molecular weight (M n ) for measuring, as well as mass-average molecular weight (M w Methods for measuring the polyvariance index (PDI) and the polyvariance index (PDI) are described later in this specification in the "Methods" section.

[0081] As previously stated herein, each side chain S1 comprises at least one polymer moiety M1 selected from the group consisting of polyester, polyether, and poly(meth)acrylate moieties, and each side chain S2, unlike polymer moiety M1, comprises at least one polymer moiety M2 selected from the group consisting of polyester, poly(meth)acrylate, polyether, polysiloxane, and polystyrene moieties.

[0082] Preferably, the side chains are not introduced into the copolymer BBCP after they have already been polymerized in a polymer-like reaction. Rather, the side chains are preferably introduced into suitable monomers used in the polymerization reaction to produce the copolymer BBCP. Since these monomers have the aforementioned polymer moieties, the corresponding monomers represent macromonomers.

[0083] Preferably, cyclic olefins, more preferably norbornene or cyclopentene monomers, are used to produce the copolymer BBCP. Polymer portions, for example M1 and M2, can be introduced into such monomers, for example, by using norbornene or cyclopentene monomers having at least one functional group, for example, a carboxylic acid group and / or a hydroxyl group. Examples of suitable norbornene monomers are: [ka] For example, (B) can be used as an initiator alcohol for polymerization, such as tin-catalyzed polymerization of lactides such as racemicalactide, to produce a polylactide macromonomer having both OH functional end groups, the other end of which can be functionalized with norbornene. The polylactide unit represents the polyester moiety as an example of polymer moiety M1. The norbornene moiety can then be used in ROMP to produce the copolymer BBCP. The production of such macromonomers is described, for example, in the supporting information by BRSveinbjoernsson et al., PNAS2012, 109(36), pp. 14332-14336. Monomer (A) can also be used to produce suitable macromonomers suitable for ROMP. For example, a polymer such as polystyrene can be produced having terminal OH groups. The terminal OH groups of this formed precursor can then be transformed into ester bonds via reaction with (A) to produce a suitable macromonomer having a polystyrene moiety as polymer moiety M2. The production of such macromonomers is described, for example, in Example 2 of WO2020 / 180427A1.

[0084] Preferably, each of the side chains S1 of the first block B1 of copolymer BBCP comprises at least one polymer moiety M1 containing at least one preferably terminal hydroxyl group, wherein polymer moiety M1 is preferably selected from the group consisting of preferably aliphatic polyester moieties and preferably aliphatic polyether moieties, and in particular represents a polylactide moiety; also preferably, each of the side chains S2 of the second block B2 of copolymer BBCP comprises at least one polymer moiety M2 that does not contain both a hydroxyl group and a carboxylic acid group, wherein polymer moiety M2 is preferably selected from the group consisting of polyethers, polysiloxanes and polystyrene moieties, and in particular represents a polystyrene moiety.

[0085] Preferably, the first block B1 of the copolymer BBCP comprises at least one structural unit SU1a and optionally at least one structural unit SU1b, wherein structural unit SU1a is represented by at least one of substructures PS1a-1 and PS1a-2, and optionally present structural unit SU1b is represented by substructure PS1b, and all structural units present in the first block are preferably randomly arranged within the first block B1 of the copolymer BBCP: [ka] [In the formula, independently of each other, Parameter x is in the range of 1 to 1000, preferably 1 to 750, more preferably 2 to 500, and even more preferably 3 to 300. Parameter a is in the range of 0 to 1000, preferably 1 to 750, more preferably 2 to 500, and even more preferably 3 to 300. The relative ratio of parameter x to parameter a is within the range of 1:0 to 1:3, preferably 2:1 to 1:2. Mx, J1, and G independently represent CH2 or C=O. Q represents a divalent alkyl, heteroalkyl, cycloalkyl, heterocycloalkyl, aryl, or heteroaryl residue. Rx represents the side chain S1 containing the polymer moiety M1, preferably C2~C6-alkylene-O-[C(=O)-C2~C6-alkylene-O] n -H represents (wherein the formula, the parameter n is in the range of 1 to 500, preferably 1 to 300), R1 represents a C1-C6 alkyl residue, preferably an unbranched C1-C6 alkyl residue.

[0086] Preferably, the second block B2 of the copolymer BBCP comprises at least one structural unit SU2a and optionally at least one structural unit SU2b, wherein structural unit SU2a is represented by at least one of substructures PS2a-1 and PS2a-2, and optionally present structural unit SU2b is represented by substructure PS2b, and all structural units present in the second block are preferably randomly arranged within the second block B2 of the copolymer BBCP: [ka] [In the formula, independently of each other, Parameter y is in the range of 1 to 1000, preferably 1 to 750, more preferably 2 to 500, and even more preferably 3 to 300. Parameter b is in the range of 0 to 1000, preferably 1 to 750, more preferably 2 to 500, and even more preferably 3 to 300. The relative ratio of parameter y to parameter b is in the range of 1:0 to 1:3, preferably 2:1 to 1:2. My, J2, and G independently represent CH2 or C=O. Q represents a divalent alkyl, heteroalkyl, cycloalkyl, heterocycloalkyl, aryl, or heteroaryl residue. Ry represents the side chain S2 containing the polymer moiety M2, preferably C1-C8-alkylene-ZT, where Z represents a C(=O)-O) or divalent N-containing heterocyclic residue, and T represents a C1-C4-alkylene residue to which the polystyrene moiety is attached. R2 represents a C1-C6 alkyl residue, preferably a branched C1-C6 alkyl residue.

[0087] Preferably, parameter a and parameter b are independently 1-300, 5-50, 50-100, 100-150, 150-200, 200-250, 250-300, 300-400, 400-500, 500-600, 600-700, 700-800, 800-900, or 900-1000. Preferably, x and y are independently 1-300, 5-50, 50-100, 100-150, 150-200, 200-250, 250-300, 300-400, 400-500, 500-600, 600-700, 700-800, 800-900, or 900-1000. Preferably, the ratio of x:a is 1:0.5 to 1:1, 1:1.5, 1:2, or 1:2.5. Preferably, the ratio of y:b is 1:0.5 to 1:1, 1:1.5, 1:2, or 1:2.5.

[0088] Preferably, a+x+b+y is in the range of 100-500, more preferably 120-480, even more preferably 140-400, still more preferably 160-350, and particularly 180-300.

[0089] The term "alkyl" refers to branched or unbranched hydrocarbons having, for example, 1 to 20 carbon atoms, often 1 to 12, 1 to 10, 1 to 8, 1 to 6, or 1 to 4 carbon atoms, or a range of carbon atoms between 1 and 20, for example 2 to 6, 3 to 6, 2 to 8, or 3 to 8 carbon atoms. Examples include, but are not limited to, methyl, ethyl, 1-propyl, 2-propyl, 1-butyl, 2-methyl-1-propyl (isobutyl), 2-butyl (sec-butyl), 2-methyl-2-propyl ( / -butyl), 1-pentyl, 2-pentyl, 3-pentyl, 2-methyl-2-butyl, 3-methyl-2-butyl, 3-methyl-1-butyl, 2-methyl-1-butyl, 1-hexyl, 2-hexyl, 3-hexyl, 2-methyl-2-pentyl, 3-methyl-2-pentyl, 4-methyl-2-pentyl, 3-methyl-3-pentyl, 2-methyl-3-pentyl, 2,3-dimethyl-2-butyl, 3,3-dimethyl-2-butyl, hexyl, octyl, decyl, and dodecyl. Alkyls may be unsubstituted or substituted. The term “heteroalkyl” is understood to be an alkyl group as defined above, preferably having at least one heteroatom selected from nitrogen, sulfur, and oxygen, and / or at least one heteroatom-containing group. The term “cycloalkyl” preferably refers to a cyclic alkyl group of 3 to 10 carbon atoms, preferably having, for example, a single cyclic ring or multiple fused rings. Examples of cycloalkyl groups include single ring structures, e.g., cyclopropyl, cyclobutyl, cyclopentyl, cyclooctyl, or multiple ring structures, e.g., adamantyl. Cycloalkyl groups may be unsubstituted or substituted. Cycloalkyl groups may be monovalent or divalent and may be optionally substituted as described for alkyl groups. Cycloalkyl groups may optionally contain one or more unsaturated moieties; for example, a cycloalkyl group may contain one or more carbon-carbon double bonds. The term “heterocycloalkyl” preferably refers to a saturated or partially saturated monocyclic, bicyclic, or polycyclic ring containing at least one heteroatom selected from nitrogen, sulfur, and oxygen, preferably 1 to 3 heteroatoms in at least one ring.Each ring is preferably 3 to 10 members, more preferably 4 to 7 members. Suitable examples of heterocycloalkyl groups include pyrrolidyl, tetrahydrofuryl, tetrahydrothiofuranil, piperidyl, piperadyl, tetrahydropyranil, morpholino, 1,3-diazapane, 1,4-diazapane, 1,4-oxatiapane, and 1,4-oxazepane. These groups may be terminal groups or bridging groups. The term "aryl" preferably refers to an aromatic hydrocarbon group. The aryl group may have 6 to 30 carbon atoms, for example, about 6 to 10 carbon atoms. Alternatively, the aryl group may have 6 to 60 carbon atoms, 6 to 120 carbon atoms, or 6 to 240 carbon atoms. The aryl group may have a single ring (e.g., phenyl) or multiple fused (fused) rings, at least one of which is aromatic (e.g., naphthyl, dihydrophenantrenyl, fluorenyl, or anthryl). Typical aryl groups include, but are not limited to, those derived from benzene, naphthalene, anthracene, and biphenyl. Aryls may be unsubstituted or optionally substituted. The term “heteroaryl” preferably refers to a monocyclic, bicyclic, or tricyclic ring system containing one, two, or three aromatic rings, at least one nitrogen, oxygen, or sulfur atom, and / or a heteroatom-containing group in the aromatic ring. Heteroaryls may be unsubstituted or substituted, for example, with one or more substituents, particularly one to three. Typical heteroaryl groups contain one or more heteroatoms in addition to 2 to 20 carbon atoms in the ring skeleton.Examples of heteroaryl groups include 2H-pyrrolyl, 3H-indolyl, 4H-quinolidinyl, acridinyl, benzo[b]thienyl, benzothiazolyl, β-carbolinyl, carbazolyl, clomenyl, cinnolinyl, dibenzo[b,d]furanyl, flazanyl, furyl, imidazolyl, imidizolyl, indazolyl, indolicinyl, indolyl, isobenzofuranyl, isoindolyl, isoquinolyl, isothiazolyl, isoxazolyl, naphthilidinyl, oxazolyl, and perimi Examples of heteroaryls include, but are not limited to, dinyl, phenanthrolinyl, phenanthrolinyl, phenalsadinyl, phenazinyl, phenothiazinyl, phenoxazinyl, phenoxazinyl, phthalazinyl, pteridinyl, prinyl, pyranyl, pyrazinyl, pyrazolyl, pyridadinyl, pyridyl, pyrimidinyl, pyrrolyl, quinazolinyl, quinolyl, quinoxalinyl, thiadiazolyl, thianthrenyl, thiazolyl, thienyl, trizolyl, tetrazolyl, and xanthenyl. Preferably, "heteroaryl" represents a monocyclic aromatic ring containing five or six ring atoms, each containing carbon and one, two, three, or four heteroatoms independently selected from non-peroxide, sulfur, and N(Z) (where Z is absent or H, O, alkyl, aryl, or (C1-C6) alkylaryl). Heteriareels may also refer to ortho-condensed bicyclic heterocycles of about 8 to 10 ring atoms derived therefrom, particularly benz derivatives, or those derived by fusing diradicals of propylene, trimethylene, or tetramethylene thereto. As used herein, the terms “substituted” or “substituent” preferably mean that one or more (e.g., 1 to 20, or 1 to 10, or 1, 2, 3, 4, or 5, or 1, 2, or 3, or 1 or 2) hydrogens on the group indicated in the expression using “substituted” (or “substituent”) are replaced with a group selected from the indicated group or a suitable group known to those skilled in the art, provided that the normal valence of the indicated atom is not exceeded and the substitution results in a stable compound.Suitable indicated groups include, for example, alkyl, alkenyl, alkynyl, alkoxy, halo, haloalkyl, hydroxy, hydroxyalkyl, aryl, heteroaryl, heterocyclyl, cycloalkyl, alkanoyl, alkoxycarbonyl, amino, alkylamino, dialkylamino, trifluoromethylthio, difluoromethyl, acylamino, nitro, trifluoromethyl, trifluoromethoxy, carboxy, carboxyalkyl, keto, thioxo, alkylthio, alkylsulfumyl, alkylsulfonyl, and cyano. In addition, non-limiting examples of substituents that can be bonded to the substituted carbon atom (or other atom) include F, Cl, Br, I, OR', OC(=O)N(R')2, CN, CF3, OCF3, R', O, S, C(=0), methylenedioxy, ethylenedioxy, N(R')2, SR', SOR', SO2R', SO2N(R')2, SO3R', C(=O)R', C(=O)C(=O)R', C(=O)CH2C(=O)R', C(=S)R', C(=O)OR', OC(=O)R', C(=O)N(R')2, OC(=O)N(R')2, C(=S)N(R')2, (CH2). 0~2 Examples include NHC(=O)R', N(R')N(R')C(=O)R', N(R')N(R')C(=O)OR', N(R')N(R')CON(R')2, N(R')SO2R', N(R')SO2N(R')2, N(R')C(=O)OR', N(R')C(=O)R', N(R')C(S)R', N(R')C(=O)N(R')2, N(R')C(S)N(R')2, N(COR')COR', N(OR')R', C(=NH)N(R')2, C(=O)N(OR')R', or C(=NOR')R' (where R' can be a hydrogen-based or carbon-based portion).

[0090] Since the main chain of copolymer BBCP preferably contains ethylenically unsaturated carbon-carbon double bonds, the structural units present in each block are preferably covalently bonded in such a way that each unit is bonded to another unit via a carbon-carbon double bond. Copolymer BBCP more preferably contains two end groups when it is linear, which is preferable. Each of these end groups is covalently bonded to one structural unit. The end groups of the copolymer (i.e., the starting or ending end) are preferably low molecular weight moieties (e.g., less than 500 Da), such as H, OH, COOH, CH2OH, CN, NH2, or hydrocarbons, such as alkyl (e.g., butyl or 2-cyanopropan-2-yl moieties at the starting and ending ends), alkenes or alkynes, or moieties resulting from elimination reactions in the first and / or last repeating units in the copolymer.

[0091] Preferably, the block copolymer BBCP is a brush block copolymer. A brush block copolymer contains a main chain (backbone) along with linear, unbranched side chains. Brushes are often characterized by densely packed, grafted chains. The confined space then strongly elongates the side chains.

[0092] Preferably, the first block B1 of the copolymer BBCP includes at least one structural unit SU1a represented by at least substructure PS1a-1, and further includes at least one structural unit SU1b represented by substructure PS1b, and the second block B2 of the copolymer BBCP includes at least one structural unit SU2a represented by at least substructure PS2a-1, and further includes at least one structural unit SU2b represented by substructure PS1b: Here, independently of each other, Parameter x is in the range of 2 to 500, preferably 3 to 300. Parameter a is in the range of 2 to 500, preferably 3 to 300. The relative ratio of parameter x to parameter a is in the range of 2:1 to 1:2, preferably 1.5:1 to 1:1.5. Parameter y is in the range of 2 to 500, preferably 3 to 300. Parameter b is in the range of 2 to 500, preferably 3 to 300. The relative ratio of parameter y to parameter b is in the range of 2:1 to 1:2, preferably 1.5:1 to 1:1.5, and the remaining residues and variables have one or more of the meanings previously defined herein.

[0093] Preferably, the coating composition, which includes at least one block copolymer BBCP used to produce the second coating layer L2, further comprises at least one preferably linear homopolymer, more preferably selected from the homopolymers of polyester, poly(meth)acrylate, polyether, polysiloxane, and polystyrene, more preferably selected from homopolymers of polystyrene, polyether, and polyester, and mixtures thereof, even more preferably selected from homopolymers of polystyrene and aliphatic polyester, such as polylactide homopolymer, and mixtures thereof, wherein the number average molecular weight (M) of the at least one copolymer BBCP is n The number average molecular weight (M) is at least 1 / 100, preferably at least 1 / 150, and more preferably at least 1 / 175 of ) n Preferably having, and preferably, the relative mass ratio of the BBCP copolymer solid to at least one homopolymer solid in the coating composition is in the range of 99:1 to 5:95, more preferably 95:5 to 10:90, even more preferably 90:10 to 15:85, still more preferably 85:15 to 20:80, still more preferably 75:25 to 25:75, and particularly 60:40 to 30:70. Number average molecular weight (M n ) for measuring, as well as mass-average molecular weight (M w Methods for measuring the polyvariance index (PDI) and the polyvariance index (PDI) are described later in this specification in the "Methods" section.

[0094] Methods for producing such homopolymers are disclosed, for example, in WO2020 / 160299A1 (pages 25 / 26, Example 1) and WO2020 / 180427A1 (pages 25 / 26, Example 1).

[0095] Preferably, at least one homopolymer is present in the second base coat composition in an amount of 0 to 90 wt.-%, preferably 20 to 80 wt.-%, more preferably 40 to 60 wt.-%, and particularly 30 to 70 wt.-%, based on the total solid content of the second base coat composition in each case.

[0096] Preferably, the relative mass ratio of the BBCP copolymer solid to the solid of at least one homopolymer in the second base coat composition is in the range of 99:1 to 5:95, preferably 95:5 to 10:90, more preferably 90:10 to 15:85, even more preferably 85:15 to 20:80, even more preferably 75:25 to 25:75, and particularly 60:40 to 30:70.

[0097] Preferably, the coating composition, which includes at least one block copolymer BBCP used to produce the second coating layer L2, includes at least one further resin, more preferably at least one polymer resin, in addition to the copolymer BBCP, and, if such homopolymer is present, in addition to the homopolymer defined above, and the relative mass ratio of the BBCP copolymer solid to the solid of the at least one further resin in the coating composition is preferably in the range of 5:95 to 100:0, more preferably 10:90 to 100:0, even more preferably 15:85 to 95:5, still more preferably 20:80 to 90:10, still more preferably 25:75 to 85:15, particularly 30:70 to 80:20, and most preferably 40:60 to 80:20.

[0098] Preferably, the coating composition, which includes at least one block copolymer BBCP used to produce the second coating layer L2, includes, in addition to copolymer BBCP, and, if homopolymers as previously defined herein are present, at least one homopolymer, and the relative mass ratio of the sum of the BBCP copolymer solid and homopolymer solid (if present) in the topcoat composition to the solid of at least one further resin is preferably in the range of 40:60 to 100:0, more preferably 45:55 to 100:0, even more preferably 50:50 to 95:5, still more preferably 55:45 to 90:10, and still more preferably 60:40 to 85:15.

[0099] In addition to copolymer BBCP and the at least one homopolymer present, at least one additional resin, preferably at least one polymer resin, optionally present in the second base coat composition, preferably functions as at least one binder (b1). The same binder, including a crosslinker (crosslinking agent), described earlier herein in relation to component (a1) and later herein in relation to component (c1), may also be used as component (b1). The at least one polymer component (b1) that is optionally present is, of course, different from copolymer BBCP and the homopolymers described above.

[0100] Coating layer L3, and coating composition used to form the said layer The third coating layer L3 is applied on top of the second coating layer L2. Thus, the third coating layer L3 is preferably located on top of the coating layer L2.

[0101] Preferably, the third coating layer L3 is a clear coat layer formed from a coating composition which is a clear coat composition, preferably a solvent-based clear coat composition, and the third coating layer L3 is preferably the outermost coating layer of a multilayer coating system. This coating composition is also referred to herein as a top coat composition and is a composition used in step (3) of the method of the present invention.

[0102] The topcoat composition may be an aqueous, i.e., water-based coating composition. Alternatively, it may be a solvent-based basecoat composition. In particular, it is, in fact, a solvent-based clearcoat composition. The topcoat composition may be a 1K (one-component) composition or a 2K (two-component) composition.

[0103] Preferably, the total solid content of the topcoat composition is in the range of 10 to 65 wt.-%, more preferably 15 to 60 wt.-%, even more preferably 20 to 50 wt.-%, and particularly 25 to 45 wt.-%, relative to the total mass of the topcoat composition in each case.

[0104] The topcoat composition preferably comprises at least one binder, more preferably at least one polymer (c1) as a binder. The same binder, which includes the crosslinking agents described above in relation to components (a1) and (b1), may also be used as component (c1).

[0105] Preferably, the topcoat composition comprises at least one polymer (c1) having an average of two or more OH groups and / or amino groups and / or carbamate groups, more preferably OH groups and / or carbamate groups. Preferably, at least one, preferably at least OH- and / or carbamate-functionalized polymer (c1) has a mass-average molecular weight M, which is measured by gel permeation chromatography (GPC) against a polystyrene standard, preferably between 800 and 100,000 g / mol, and more particularly between 1,000 and 75,000 g / mol. wIt has.

[0106] When the topcoat composition is formulated as a 2K coating composition, it preferably contains, as at least one further polymer (c1) present therein, at least one polyisocyanate having free NCO groups as a crosslinking agent. When the topcoat composition is formulated as a 1K coating composition, it preferably contains, as at least one further polymer (c1) present therein, at least one polyisocyanate having blocked NCO groups and / or at least one melamine-formaldehyde resin as a crosslinking agent.

[0107] A suitable component (c1) for use as a crosslinking agent is an organic component having an average of two or more NCO groups. At least one organic component used as a crosslinking agent preferably has an alicyclic structure and / or parent structure derived from an alicyclic polyisocyanate by trimerization, dimerization, urethane formation, biuret formation, uretdione formation and / or allophanate formation. Alternatively or additionally, at least one organic component used as a crosslinking agent preferably has an acyclic aliphatic structure and / or parent structure derived from an acyclic aliphatic polyisocyanate by trimerization, dimerization, urethane formation, biuret formation, uretdione formation and / or allophanate formation. The acyclic aliphatic polyisocyanate (which optionally acts as the parent structure) is a known, preferably substituted or unsubstituted, aliphatic polyisocyanate. Examples include tetramethylene 1,4-diisocyanate, hexamethylene 1,6-diisocyanate, 2,2,4-trimethylhexane 1,6-diisocyanate, ethylene diisocyanate, dodecane 1,12-diisocyanate, and mixtures of the aforementioned polyisocyanates. Alicyclic polyisocyanates (which optionally act as the parent structure) are known, preferably substituted or unsubstituted, alicyclic polyisocyanates. Preferred polyisocyanates include isophorone diisocyanate, cyclobutane 1,3-diisocyanate, cyclohexane 1,3-diisocyanate, cyclohexane 1,4-diisocyanate, methylcyclohexyl diisocyanate, hexahydrotoluene 2,4-diisocyanate, hexahydrotoluene 2,6-diisocyanate, hexahydrophenylene 1,3-diisocyanate, hexahydrophenylene 1,4-diisocyanate, perhydrodiphenylmethane 2,4'-diisocyanate, 4,4'-methylenedicyclohexyl diisocyanate (e.g., Desmodur® W from Bayer AG), and mixtures of the aforementioned polyisocyanates. The organic components listed above, having an average of two or more NCO groups, can also be partially silanized.Such silane-based crosslinking agents are disclosed, for example, in WO2010 / 063332A1, WO2010 / 139375A1, and WO2009 / 077181A1.

[0108] In particular, when the topcoat composition is formulated as a 1K coating composition, a suitable component (c1) for use as a crosslinking agent is melamine formaldehyde resin. In relation to component (a1), the same melamine formaldehyde resin previously discussed herein may be used.

[0109] Preferably, the top coat composition 3) does not contain copolymers (BBCPs) present in the second base coat composition.

[0110] The topcoat composition does not have to be pigmented. However, even when formulated as a clearcoat composition, the topcoat composition may optionally contain a coloring and / or effect pigment, preferably a coloring pigment, in an amount that does not interfere with the desired transparency of the clearcoat once cured. For example, the clearcoat composition may contain at least one coloring pigment in an amount of up to 7.5 wt.-%, preferably up to 5.0 wt.-%, more preferably up to 2.5 wt.-%, and still more preferably up to 1.5 wt.-%, based on the total solids content of the clearcoat composition in each case. The same applies to fillers that are optionally present in the clearcoat composition. However, preferably, the clearcoat composition does not contain pigments and / or fillers.

[0111] Method of the present invention The present invention provides a method for manufacturing the multilayer coating system of the present invention on an optionally pre-coated substrate, comprising at least steps (1), (2), (3), and (4).

[0112] The method of the present invention is suitable for both automotive OEM applications and repainting applications, and is particularly suitable for automotive OEM applications.

[0113] Preferably, each of steps (1) to (3) is carried out via spray application.

[0114] At least the second and third coating films, but optionally the first coating film as well, are preferably uncured coating films at this stage (after each step has been performed). Therefore, the coating composition applied in at least step (3) is preferably applied wet-on-wet onto the second coating film obtained after step (2) has been performed. If only the obtained second and third coating films are cured together in step (4), the method of the present invention is the 2C1B method. In this case, the first coating film applied in step (1) is cured before step (2) is performed. However, in an alternative method, the coating composition applied in step (2) is also preferably applied wet-on-wet onto the first coating film obtained after step (1) has been performed. In this case, when step (2) is performed, the first coating film is still an uncured coating film. If the obtained first, second, and third coating films are cured together in step (4), the method of the present invention is the 3C1B method.

[0115] Process (1) According to step (1), a dyed base coat composition is applied to at least a portion of an optionally pre-coated substrate, and a first coating film is formed on at least a portion of the optionally pre-coated substrate. The base coat composition used in step (1) of the method of the present invention is also referred to as the "first base coat composition".

[0116] Any step (1a) Preferably, the method of the present invention further includes step (1a), which is carried out after step (1) and before step (2). In step (1a), the first coating film obtained after step (1) is flushed off for a period of preferably 1 to 20 minutes, more preferably 2 to 15 minutes, and particularly 5 to 10 minutes, before the second base coat composition is applied in step (2). Preferably, step (1a) is carried out at a temperature not exceeding 40°C, more preferably in the range of 18 to 30°C.

[0117] In the sense of the present invention, the term "flushing off" preferably means drying, in which at least some and / or some amount of solvent (water and / or organic solvent) is evaporated from the coating film before the next coating composition is applied and / or curing is performed. Curing is not performed by flushing off.

[0118] Any step (1b) Preferably, the method of the present invention further includes step (1b), which is carried out after step (1) or step (1a) and before step (2). In step (1b), the first coating film obtained after step (1) or (1a) is cured before the second base coat composition is applied in step (2). In connection with step (4), the same curing conditions outlined in detail later herein may be used / applied.

[0119] Preferably, steps (1a) and / or (1b) are carried out. More preferably, at least step (1b) is carried out such that the second base coat composition applied in step (2) is applied onto the cured first coating film.

[0120] Process (2) According to step (2), a second base coat composition, which includes at least one block copolymer BBCP and is different from the base coat composition applied in step (1), is applied to the first coating film present on the substrate obtained after step (1), forming a second coating film, which is preferably adjacent to the first coating film.

[0121] Step (2) may be performed before curing the first coating film obtained after step (1). Alternatively, and preferably, step (2) may be performed after curing the first coating film obtained after step (1), i.e., after performing at least any step (1b).

[0122] Any step (2a) Preferably, the method of the present invention further includes step (2a), which is carried out after step (2) and before step (3). In step (2a), the second coating film obtained after step (2) is flashed off for a period of preferably 1 to 20 minutes, more preferably 2 to 15 minutes, and particularly 5 to 10 minutes, before the application of the topcoat composition in step (3). Preferably, step (2a) is carried out at a temperature not exceeding 40°C, more preferably in the range of 18 to 30°C.

[0123] Process (3) In step (3), a coating composition different from the compositions applied in steps (1) and (2) is applied to a second coating film present on the substrate obtained after step (2), forming a third coating film, which is preferably adjacent to the second coating film, and the coating composition is a topcoat composition, preferably a clearcoat composition.

[0124] Preferably, the third coating film obtained after step (3) is the outermost film of the formed multilayer coating system.

[0125] Any step (3a) Preferably, the method of the present invention further includes step (3a), which is carried out after step (3) and before step (4). In step (3a), the third coating film obtained after step (3) is flashed off for a period of preferably 1 to 20 minutes, more preferably 2 to 15 minutes, and particularly 5 to 10 minutes, before carrying out the curing step (4). Preferably, step (3a) is carried out at a temperature not exceeding 40°C, more preferably in the range of 18 to 30°C.

[0126] Process (4) According to step (4), at least the second and third coating films applied in steps (2) and (3), and optionally the first coating film applied in step (1) (if the first coating film was not cured before step (2)) are cured together, i.e., simultaneously, to obtain a multilayer coating system comprising at least the first, second, and third coating layers L1, L2, and L3. Each of the obtained cured coating films represents a coating layer.

[0127] Preferably, step (4) is carried out at a temperature below 180°C, preferably below 160°C, more preferably below 150°C, particularly within the range of 15 to <180°C or 15 to <160°C, for a period of 5 to 45 minutes, preferably 20 to 45 minutes, particularly 25 to 35 minutes. However, preferably, the minimum curing temperature applied in step (4) is at least 80°C. In this case, curing by step (4) is preferably carried out at a temperature within the range of 80 to <180°C or 80 to <160°C.

[0128] Preferably, the curing in step (4) is selected from chemical curing, e.g., chemical crosslinking, irradiation curing, and / or physical drying (non-chemical curing), at room temperature or at a higher temperature, in each case, and more preferably, the minimum curing temperature applied in step (4) is at least 80°C, at room temperature or at a higher temperature.

[0129] Coated substrate of the present invention A further subject of the present invention is a coated substrate that can be obtained by the method of the present invention.

[0130] In relation to the methods and multilayer coating systems of the present invention, all preferred embodiments described herein are also preferred embodiments with respect to the coated substrates of the present invention as described above.

[0131] Method of using the present invention A further subject of the present invention is to improve, and more preferably to improve, the chromaticity of, the multilayer coating system of the present invention, a coating composition comprising at least one block copolymer BBCP used in the present invention, particularly its C* 平均 A method used to increase the saturation value, and the aforementioned C* 平均 The saturation value, especially when the coating composition is used as the second base coat composition in step (2) of the method of the present invention, is more preferably improved by the sum of the C* values ​​(saturation values ​​according to the L*C*h color model) measured at angles of 15°, 45°, and 110°, particularly its C* 平均 A saturation value of at least 40, preferably at least 42, more preferably at least 45, even more preferably at least 50, even more preferably at least 55, and especially at least 60 C* 平均 It was divided by 3 to raise the value.

[0132] All preferred embodiments described herein in relation to the method, multilayer coating system, and coated substrate of the present invention are also preferred embodiments of the method of use of the present invention as described above.

[0133] method 1. Determine the non-volatile fraction. The amount of solids (non-volatile matter, solid fraction), including the total solids, is determined by 60 minutes at 110°C according to DIN EN ISO3251:2019-09.

[0134] 2.M n M w and measurement of PDI Polymer molecular weight (number average molecular weight (M n ) and mass-average molecular weight (M W The molecular weight and PDI (polydispersion index) were determined via gel permeation chromatography (GPC) using a combination of differential refractive index (dRI) and two light scattering (LS) detectors. The use of LS detectors allows for the analysis of absolute molecular weight for polymer samples. The solvent for all samples was tetrahydrofuran (THF) at an elution rate of 1.0 mL / min. Polymer samples were completely dissolved in HPLC-grade THF at concentrations ranging from 2.5 to 7.5 mg / mL, filtered through a 0.5 μm syringe, and injected via an autosampler. The porous column stationary phase consisted of two Malvern T600 single-pore columns with an exclusion limit of 20,000,000 Da for poly(styrene). Molecular weight and PDI were determined via OMNISEC software.

[0135] 3. Color values ​​(L* and C*) and R f Value and λ max Measurement of Values The L*a*b* color space or L*a*b* color model (i.e., the CIELAB color model) is known to those skilled in the art. The L*a*b* color model is standardized, for example, in DIN EN ISO / CIE11664-4:2020-03. Each perceptible color in the L*a*b* color space is described by the position of a particular color using coordinates {L*, a*, b*} in a three-dimensional coordinate system. The a* axis describes the green or red part of a color, with negative values ​​representing green and positive values ​​representing red. The b* axis describes the blue or yellow part of a color, with negative values ​​representing blue and positive values ​​representing yellow. Smaller numbers thus indicate bluer colors. The L* axis is perpendicular to this plane and represents brightness. The L*C*h color model is similar to the L*a*b* color model and utilizes the same diagrams as the L*a*b* color model, but uses cylindrical coordinates instead of Cartesian coordinates. In the L*C*h color model, L* also represents brightness, C* represents chroma, and h is the hue angle. The value of chroma C* is the distance from the brightness axis (L*). The color values ​​L* and C* of coated substrates before or after firing are determined after manufacturing in accordance with ASTM E284-81a. These values ​​are measured using the BYK-mac i (BYK-Gardner) instrument. Sample analysis is performed according to the BYK-mac i spectrophotometer standard operating procedure, in accordance with the measurement of color, brightness, and granularity. The sample to be analyzed is carefully wiped clean with a microfiber cloth. Then, the BYK-mac i instrument is placed on the substrate surface, and measurements are taken using a D65 light source at angles of 15°, 45°, and 110°, and the data is recorded for each angle. This measurement is taken at least three different positions on each panel, and the values ​​are averaged over the test and reported. λ max The values ​​were measured on the x-axis of the reflectance curve obtained using a BYK-mac i spectrophotometer at angles of 15°, 45°, and 110°, and the data was recorded for each angle. The reflectance value (R f ) is the maximum within the measurement window of 400nm to 700nm. fThe values ​​were measured on the y-axis of the reflectance curve obtained using a BYK-mac i spectrophotometer at angles of 15°, 45°, and 110°, and the data was recorded for each angle. The reflectance value (R f ) is the maximum within the measurement window of 400nm to 700nm. [Examples]

[0136] The following embodiments further illustrate the present invention, but should not be construed as limiting its scope. "Pbw" means parts by mass. Unless otherwise defined, "parts" means "parts by mass."

[0137] 1. Production of copolymers used in the present invention In a 2000 mL container under an inert atmosphere, norbornene-functionalized polylactide macromonomer (PLA-MM) (29.14 mmol, 3.2 6 M n PLA-MM was prepared by equimolar addition to dichloromethane. PLA-MM was first prepared via tin-catalyzed ring-opening polymerization of lactide using a norbornene alcohol initiator to obtain OH-functional and norbornene-functionalized polylactide macromonomer PLA-MM. PLA-MM was prepared by the general method described in the supporting information by BRSveinbjoernsson et al., PNAS2012, 109(36), pp. 14332-14336. Then, a bis-bipyridineruthenium catalyst was rapidly added to the mixture of PLA-MM and d,x-DME to prepare PLA. 100 -r-DME 100 Copolymerization targeting was initiated. "r" means that the two monomer units PLA and DME are randomly arranged. The mixture was stirred at room temperature for 45 minutes (first block mixture). In separate containers under an inert atmosphere, norbornene-functionalized polystyrene macromonomer (PS-MM, 3.8) was added. 3 M nA solution of (containing) and d,x-DIPE (diisopropyl-5-norbornene-2,3-dicarboxylate, d=endo, x=exo) was prepared in dichloromethane (second block mixture). PS-MM was first prepared in two steps by the general method described in Example 2 of WO2020 / 180427A1, and the OH-functional polymerization precursor of PS-MM was prepared by polymerization of styrene in toluene with sec-butyllithium as an initiator. After chain termination by the addition of propylene oxide, followed by methanol, quenching was carried out. The terminal OH groups of the formed precursor were then converted to ester bonds via reaction with norbornenecarboxylic acid to obtain PS-MM. A solution of PS-MM and d,-DIPE was rapidly added to the first block reaction mixture. The two monomer units PS and DIPE were randomly arranged in the second block in which the copolymer was formed. The resulting mixture was stirred at room temperature for a further 4 hours, and then quenched by the addition of ethyl vinyl ether. Next, the quenched catalyst was captured using a functionalized silica gel absorbent, and the mixture was stirred for approximately 4 hours. The mixture was filtered, and the solution was concentrated under reduced pressure. The solid copolymer was obtained after removing the solvent. This was dried in a vacuum oven at 75°C for 4 hours to remove any remaining solvent. The obtained product (BBCP1) was used in this form.

[0138] BBCP1 is 788. 3 Number average molecular weight (M n ), and 865. 7 Mass average molecular weight (M w It had ) and the multivariance index (PDI) was 1.10 accordingly.

[0139] 2. Preparation of BBCP1 containing the coating composition 2.1 Base coat compositions BC1-BC5 BC1 was prepared by preparing a solution of 1.80 g of BBCP1, 0.60 g of polystyrene homopolymer (PS-HP), 0.60 g of polylactide homopolymer (PLA-HP), and 7 g of n-butyl acetate. In BC1, the relative mass ratio of BBCP1 solid to the combined solid of PS-HP and PLA-HP was set to 60:40.

[0140] BC2 was prepared by creating a solution of 1.65 g of BBCP1, 0.68 g of polystyrene homopolymer (PS-HP), 0.68 g of polylactide homopolymer (PLA-HP), and 7 g of n-butyl acetate. In BC2, the relative mass ratio of BBCP1 solid to the combined solid of PS-HP and PLA-HP was set to 55:45.

[0141] BC3 was prepared by creating a solution of 1.50 g of BBCP1, 0.75 g of polystyrene homopolymer (PS-HP), 0.75 g of polylactide homopolymer (PLA-HP), and 7 g of n-butyl acetate. In BC3, the relative mass ratio of BBCP1 solid to the combined solids of PS-HP and PLA-HP was set to 50:50.

[0142] BC4 was obtained by preparing a solution of 1.38 g of BBCP1, 0.81 g of polystyrene homopolymer (PS-HP), 0.81 g of polylactide homopolymer (PLA-HP), and 7 g of n-butyl acetate. BC1 had a solid content of 30 wt.-%. The relative mass ratio of BBCP1 solid to the combined solid of PS-HP and PLA-HP in BC4 was 46:54.

[0143] BC5 was prepared by preparing a solution of 1.20 g of BBCP1, 0.90 g of polystyrene homopolymer (PS-HP), 0.90 g of polylactide homopolymer (PLA-HP), and 7 g of n-butyl acetate. In BC5, the relative mass ratio of BBCP1 solid to the combined solid of PS-HP and PLA-HP was set to 40:60.

[0144] The polystyrene homopolymer (PS-HP) used was 3.9 5 M n It had the following properties. The polylactide homopolymer (PLA-HP) used was 4.2 6 M n He possessed it.

[0145] 2.2 Base coat composition BC4a A diluted composition of BC4 was prepared. Base coat composition BC4a was obtained by mixing 90 pbw (parts by mass) of BC4 with 10 pbw of n-butyl acetate.

[0146] 2.3 Base coat compositions BC1b, BC3b, BC4b, BC5b and BC4c Base coat composition BC1b was obtained by mixing 85 parts by mass of BC1 with 15 parts by mass of R10CG392A. Base coat composition BC3b was obtained by mixing 85 parts by mass of BC3 with 15 parts by mass of R10CG392A. Base coat composition BC4b was obtained by mixing 85 parts by mass of BC4 with 15 parts by mass of R10CG392A. Base coat composition BC5b was obtained by mixing 85 parts by mass of BC5 with 15 parts by mass of R10CG392A. Base coat composition BC4c was obtained by mixing 90 parts by mass of BC4 with 10 parts by mass of R10CG392A.

[0147] R10CG392A is a commercially available 1K high-solidity clear coat composition. R10CG392A was mixed with each base coat under stirring in each case.

[0148] 2.4 Base coat compositions BC4-CC1, BC4-CC2, BC4-CC3, BC4-CC4 and BC4-CC5 BC4-CC1 was obtained by mixing 84.7 pbw (parts by mass) of BC4 with 15.3 pbw of R10CG392D. R10CG392D is a commercially available 1K clear coat composition. BC4-CC2 was obtained by mixing 84.4 pbw (parts by mass) of BC4 with 15.6 pbw of R10CG062T. R10CG062T is a commercially available Uregloss CW® 1K clear coat composition. BC4-CC3 was obtained by mixing 83.9 pbw (parts by mass) of BC4 with 16.1 pbw of E126CG300. E126CG300 is a commercially available Stargloss® 1K clear coat composition. BC4-CC4 was obtained by mixing 85.4 pbw (parts by mass) of BC4 with 14.6 pbw of a commercially available 2K Progloss® clear coat composition. The 2K clear coat composition was then prepared by mixing 1 pbw of its B component (N52CG081) with 3.75 pbw of its A component (E10CG081G). BC4-CC5 was obtained by mixing 84.8 pbw (parts by mass) of BC4 with 15.2 pbw of a commercially available 2K iGloss® clear coat composition. The 2K clear coat composition was then prepared by mixing 1 pbw of its B component (N52CG500) with 1 pbw of its A component (E10CG500B).

[0149] 3. Manufacturing of multilayer coating systems A steel panel with a cured primer coat was used as the substrate. A commercially available black base coat (E487KU414T Agate Black or E387KU343C Shadow Black) was sprayed onto the primer coat as the first base coat and cured at approximately 129°C (265°F) for 25 minutes. The dry film layer thickness of the resulting black base coat was in the range of approximately 16.5 μm to 19.0 μm (0.65 to 0.75 mil). Next, one of the base coat compositions BC1-BC5, BC1b, BC3b, BC5b, BC4a, BC4b, and BC4c, as well as BC4-CC1, BC4-CC2, BC4-CC3, BC4-CC4, and BC4-CC5, was applied as a second base coat (midcoat) composition to the cured first base coat film using a drawdown bar, at 200 μm intervals on a standard drawdown bar applicator available from Byk, in an amount that would result in a dry film layer thickness of 27-54 μm after subsequent firing. After applying the second base coat composition, flush off at room temperature (23°C) for up to 10 minutes, then apply a commercially available clear coat composition CC1 (R10CG392D, 1K clear coat composition), CC2 (R10CG062T, Uregloss® 1K clear coat composition), CC3 (E126CG300, Stargloss® 1K clear coat composition), CC4 (E10CG081G+N52CG081, 2K One of the following was sprayed as a clear coat on an uncured / unbaked second base coat film using a wet-on-wet method, in an amount that would result in a dry film layer thickness of 45-55 μm for the clear coat layer after subsequent baking: Progloss® clear coat composition (1 lbw of component B (N52CG081) added to 3.75 lbw of component A (E10CG081G)) and CC5 (E10CG500B + N52CG500, iGloss® 2K clear coat composition (1 lbw of component B (N52CG500) added to 1 lbw of component A (E10CG500B))). The two coated films were then baked together at approximately 140°C (285°F) or approximately 130°C (265°F) for 30 minutes.In an alternative method, base coat composition BC4 was applied as a top coat to a cured first base coat film (no clear coat was applied). In comparative experiments, the resulting top coat film was baked at approximately 140°C (285°F) for 30 minutes or dried at 24°C (75°F) for 24 hours. In addition, comparative experiments were conducted, and in each case, no clear coat composition was applied. Instead, one of the base coat compositions BC4, BC4a, BC1b, BC4b, and BC5b was applied as a top coat composition, not as a second base coat (mid coat) composition, but solely for comparative purposes.

[0150] 4. Properties of substrates coated with multilayer coating systems As outlined in item 3, each of the resulting coated substrates is evaluated based on its color value C* and its R f Value and λ max The values ​​were investigated. These values ​​were measured according to the methods disclosed in the "Methods" section. The measured values ​​are shown in Tables 1-9. C* 平均 This is the C* value obtained by dividing the sum of the C* values ​​measured at 15°, 45°, and 110° by 3.

[0151] [Table 1]

[0152] [Table 2]

[0153] [Table 3]

[0154] The data presented in Tables 1a, 1b, 2, 3a, and 3b demonstrate that applying a clear coat composition to an unfired BBCP1-containing midcoat film to obtain a clear coat film, and then firing the two films together, results in a multilayer coating system with particularly improved chromaticity (increased saturation C* value). Table 2, in particular, clearly shows a strong shift from a reddish to a greenish appearance, which is often desirable. The data presented in Table 3 further confirms this. In addition, saturation can even be further increased when using any of BC1b, BC4b, or BC5b.

[0155] [Table 4]

[0156] [Table 5]

[0157] [Table 6]

[0158] [Table 7]

[0159] [Table 8]

[0160] [Table 9]

[0161] The data presented in Tables 4-8 demonstrate that applying a variety of chemically distinct clear coat compositions onto an unbaked BBCP1-containing midcoat film, followed by baking the films together, results in a multilayer coating system with excellent chromaticity (increased saturation C* value) in all cases. This is summarized in Table 9. Table 9 further clarifies that the presence of the clear coat on the BBCP1-containing midcoat prevents the color shift observed during baking. It was found that when the clear coat is not applied on the BBCP1-containing coat (i.e., the coat represents the top layer) and the coat is baked, a significant decrease in saturation occurs in some cases, which is undesirable. However, applying the clear coat onto an unbaked BBCP1-containing film, followed by baking the two films, unexpectedly prevents this decrease in saturation. This decrease in saturation is also not observed when the BBCP1-containing coat is dried instead of baked. However, replacing firing with drying is undesirable and disadvantageous from an economic standpoint, as the process of this method must be sped up as much as possible in OEM assembly.

Claims

1. At least three distinct coating layers L1, L2, and L3 are present on the substrate, i.e. A first dye coating layer L1 applied on at least a portion of the substrate, A second coating layer L2 applied on the first pigmented coating layer L1, and A third coating layer L3 applied on top of the second coating layer L2. In a multilayer coating system equipped with, The second coating layer L2 is formed from a coating composition comprising a main chain and at least one block copolymer containing at least two blocks B1 and B2 that are different from each other. The main chain of the block copolymer contains an ethylenically unsaturated carbon-carbon double bond, and the block copolymer is obtained by ring-opening metathesis polymerization (ROMP) using a cyclic ethylenically unsaturated monomer. Block B1 includes at least one type of side chain S1 bonded to the main chain, and Block B2 includes at least one type of side chain S2 bonded to the main chain, different from side chain S1, and side chain S1 includes at least one polymer portion M1 selected from the group consisting of polyester, polyether and poly(meth)acrylate portions, and side chain S2 includes at least one polymer portion M2, different from polymer portion M1, selected from the group consisting of polyester, poly(meth)acrylate, polyether, polysiloxane and polystyrene portions, The first block B1 of the copolymer comprises at least one structural unit SU1a, or at least one structural unit SU1a and at least one structural unit SU1b, wherein structural unit SU1a is represented by at least one of substructures PS1a-1 and PS1a-2, and structural unit SU1b is represented by substructure PS1b. 【Chemistry 1】 [In the formula, independently of each other, Parameter x is within the range of 1 to 1000. Parameter a is within the range of 0 to 1000. The relative ratio of parameter x to parameter a is within the range of 1:0 to 1:

3. Mx, J １ And G are independent of each other, CH ２ Or it represents C=O, Q represents a divalent alkyl, heteroalkyl, cycloalkyl, heterocycloalkyl, aryl, or heteroaryl residue. Rx represents the side chain S1 containing the polymer portion M1, R １ C １ ~C ６ - Represents alkyl residues, and The second block B2 of the copolymer comprises at least one structural unit SU2a, or at least one structural unit SU2a and at least one structural unit SU2b, wherein structural unit SU2a is represented by at least one of substructures PS2a-1 and PS2a-2, and structural unit SU2b is represented by substructure PS2b: 【Chemistry 2】 [In the formula, independently of each other, The parameter y is in the range of 1 to 1000. Parameter b is in the range of 0 to 1000. The relative ratio of parameter y to parameter b is within the range of 1:0 to 1:

3. My, J ２ And G are independent of each other, CH ２ Or it represents C=O, Q represents a divalent alkyl, heteroalkyl, cycloalkyl, heterocycloalkyl, aryl, or heteroaryl residue. Ry represents the side chain S2 containing the polymer portion M2, R ２ represents a C １ to C ６ -alkyl residue], characterized in that Multi-layer coating system.

2. The multilayer coating system according to claim 1, characterized in that the coating composition comprising at least one block copolymer is free of any dyes or is a dyed coating composition.

3. The multilayer coating system according to claim 1 or 2, characterized in that the first pigmented coating layer L1 is capable of absorbing wavelengths that are not reflected by at least the second layer L2.

4. The multilayer coating system according to any one of claims 1 to 3, characterized in that the third coating layer L3 is formed from a clear coat composition, and the third coating layer L3 is the outermost coating layer of the multilayer coating system.

5. A multilayer coating system according to any one of claims 1 to 4, characterized in that at least the second and third coating layers L2 and L3 are located adjacent to each other.

6. At least 40 C* 平均 It has a value, C* 平均 The multilayer coating system according to any one of claims 1 to 5, characterized in that the value is obtained by dividing the sum of the C* values ​​(saturation values ​​according to the L*C*h color model) measured at angles of 15°, 45°, and 110° by 3.

7. A multilayer coating system according to any one of claims 1 to 6, characterized in that the cyclic ethylenically unsaturated monomer is a cyclic olefinic monomer.

8. The side chain S1 of the first block B1 of the copolymer comprises at least one polymer moiety M1 containing at least one terminal hydroxyl group, and the polymer moiety M1 is selected from the group consisting of aliphatic polyester moieties and aliphatic polyether moieties, and The side chain S2 of the second block B2 of the copolymer comprises at least one polymer moiety M2 that does not contain both a hydroxyl group and a carboxylic acid group, and the polymer moiety M2 is selected from the group consisting of polyethers, polysiloxanes, and polystyrene moieties. A multilayer coating system according to any one of claims 1 to 7.

9. At least one copolymer has a number average molecular weight (M) in the range of 450,000 to 3,000,000. ｎ A multilayer coating system according to any one of claims 1 to 8, characterized by having ).

10. A multilayer coating system according to any one of claims 1 to 9, characterized in that all structural units present in the first block B1 of the copolymer are randomly arranged within the first block B1, and all structural units present in the second block B2 of the copolymer are randomly arranged within the second block B2 of the copolymer.

11. The multilayer coating system according to any one of claims 1 to 10, characterized in that at least one copolymer is present in the coating composition used to produce the second coating layer L2 in an amount ranging from 10 to 100 wt.-% with respect to the total solid content of the coating composition.

12. The multilayer coating system according to any one of claims 1 to 11, characterized in that the coating composition used to produce the second coating layer L2 further comprises at least one block copolymer selected from homopolymers of polyester, poly(meth)acrylate, polyether, polysiloxane, and polystyrene, and mixtures thereof.

13. At least one homopolymer has a number-average molecular weight (M) of at least one copolymer. ｎ ) is at least 1 / 100th of the number average molecular weight (M ｎ The multilayer coating system according to claim 12, characterized by having ).

14. The multilayer coating system according to claim 12 or 13, characterized in that the relative mass ratio of the copolymer solid to at least one homopolymer solid in the coating composition is in the range of 99:1 to 5:

95.

15. A multilayer coating system according to any one of claims 1 to 14, characterized in that a coating composition used to produce a second coating layer L2 comprises, in addition to the copolymer, and, if such homopolymer is present, in addition to the homopolymer described in claim 12, at least one further resin, wherein the relative mass ratio of the copolymer solid to the solid of the at least one further resin in the coating composition is in the range of 5:95 to 100:

0.

16. A method for producing a multilayer coating system according to any one of claims 1 to 15, comprising at least steps (1), (2), (3), and (4), i.e. (1) A step of applying a dyed base coat composition to at least a portion of the substrate to form a first coating film on at least a portion of the substrate, (2) A step of applying a second base coat composition, which comprises at least one block copolymer and is different from the base coat composition applied in step (1), to the first coating film present on the substrate obtained after step (1) to form a second coating film, (3) A step of applying a coating composition different from the compositions applied in steps (1) and (2) to a second coating film present on a substrate obtained after step (2) to form a third coating film, wherein the coating composition is a clear coat composition. (4) A step of curing together at least the second and third coating films applied in steps (2) and (3), or, if the first coating film was not cured before step (2), further curing together the first coating film applied in step (1) to obtain a multilayer coating system comprising at least the first, second, and third coating layers L1, L2, and L3. Methods that include...

17. A method for using a coating composition comprising at least one block copolymer as described in any one of claims 1 to 15 to improve the chromaticity of a multilayer coating system as described in any one of claims 1 to 15.

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