Clearcoat compositions for providing clearcoats with stable gloss across varying dry layer thicknesses

Abstract

The present invention relates to a clearcoat system comprising a component A) comprising in turn at least one OH- functional polymer a1), at least two kinds of silica constituents, namely at least one kind of fumed silica as constituent a2), and at least one kind of amorphous silica matting agent as constituent a3), which is different from constituent a2), wherein the weight amount of constituent a3) exceeds the weight amount of constituent a2), and wherein the amount of constituent a3) in component A) is at least 2.5 wt.-%, based on the total weight of component A), and a component B) comprising in turn at least one organic constituent b1) bearing on average two or more isocyanate groups, wherein at least a part of these isocyanate groups has been reacted with at least one silane prior to incorporation of constituent b1) into component B), a clearcoat composition obtainable by mixing at least components A) and B), a method of coating a substrate making use of said clearcoat composition, a coated substrate obtainable by this method, and to a multilayer coating system comprising at least two coatings layers L1 and L3, wherein layer L3 is obtainable from the clearcoat composition.

Description

[0001] 220842W001 1 L023824PCT 1 October 7, 2025

[0002] BASF Coatings GmbH

[0003] Clearcoat compositions for providing clearcoats with stable gloss across varying dry layer thicknesses

[0004] The present invention relates to a clearcoat system, a clearcoat composition obtainable therefrom, a method of coating a substrate making use of said clearcoat composition, a coated substrate obtainable by this method, and to a multilayer coating system inter alia comprising a coating layer obtainable from applying the clearcoat composition.

[0005] Background of the invention

[0006] In today's automobile finishing different substrates are painted such as bodies and bodywork parts produced from, e.g., metal substrates. Usually in such applications, multicoat paint systems are constructed. Multicoat paint systems on metallic substrates conventionally comprise an electrodeposition coat, a primer-surfacer coat and / or a filler and / or at least one basecoat, and a topcoat such as a clearcoat. In such systems it is the clearcoats in particular that define such essential technical properties as, for example, the gloss, distinctiveness of image (DOI), weathering stability and scratch resistance.

[0007] Clearcoat compositions are, e.g., disclosed in WO 2013 / 076208 A1 and WO 2012 / 140131 A1 , which both relate to a 2K solvent-based clearcoat coating system comprising inter alia two different (meth)acrylic OH-functional copolymers, a polyamide, and a urea compound. Further clearcoat compositions are, e.g., disclosed in WO 2009 / 077181 A1 , which relates to a coating composition comprising inter alia an OH-functional binder, an NCO- functional crosslinker, which can be partially modified by using a silane, and a moisture captor.

[0008] Additional clearcoat compositions are, e.g., disclosed in WO 2014 / 086530 A1 , WO 2014 / 086529 A1 , and WO 2022 / 200533 A1. WO 2014 / 086530 A1 aims at providing coatings having a high scratch resistance, good polishability and a good appearance determined by measuring the waviness. WO 2014 / 086529 A1 aims at providing coatings having a reduced tendency toward whitening under moisture exposure and a good overall appearance determined by measuring the waviness. The clearcoat compositions disclosed in WO 2014 / 086530 A1 and WO 2014 / 086529 A1 inter alia contain an OH-functional binder, fumed silica and a polyisocyanate, which is present in a partially silane modified form. WO 2022 / 200533 A1 aims at providing clearcoat compositions, which can be used to prepare clearcoats, which in turn show no or at least a minimized whitening after exposure to humidity and / or moisture. The 2K clearcoat systems disclosed in WO 2022 / 200533 A1 , which are used to prepare suitable clearcoat compositions, inter alia contain an OH-functional binder, at least one kind of fumed silica, a urea moiety or moieties containing constituent, and a polyisocyanate, which is present in a partially silane modified form. The relative weight ratio of the urea moiety or moieties containing constituent and the at least one kind of fumed silica to each other is at most 10:1.

[0009] In particular, in today's automotive OEM applications the customer's focus on appearance properties is increasing. To fulfil the demanding requirements and specifications of premium OEM finishes, the clearcoat coating 220842W001 1 L023824PCT 2 October 7, 2025

[0010] BASF Coatings GmbH compositions used need particularly to be able to provide an excellent gloss. The dry layer thicknesses of the multilayer coating systems including the clearcoat layers applied on the car body, however, vary to a not insignificant extent on the different areas and parts of said car body, which may lead to a variation of the gloss in these areas and parts of the car and thus result in a non-stable gloss across the overall car body. This is, of course, undesired, in particular from the customer's perspective. Such a non-stable gloss is in particular often problematic, when matt clearcoat compositions are used to provide matt clearcoat layers, since the gloss in matt coatings is typically a function of the dry layer thickness.

[0011] Thus, there is a need for providing clearcoat compositions, which can be used to prepare clearcoats, which in turn can be used for coating a variety of substrates such as car bodies, in particular for automotive OEM applications, e.g., as outermost layer of a multilayer coating system being present on said car bodies, wherein said clearcoats, when the clearcoats are matt clearcoats, exhibit not only an excellent gloss, but also at the same time a stable gloss, which does not or at least not significantly vary across the different areas and parts of the car body, even when there are variations of the dry layer thicknesses across these areas and parts, e.g., of about 10 pirn or even more.

[0012] Problem

[0013] It has been therefore an objective underlying the present invention to provide clearcoat compositions, which can be used to prepare clearcoats, which in turn can be used for coating a variety of substrates such as car bodies, in particular for automotive OEM applications, e.g., as outermost layer of a multilayer coating system being present on said car bodies, wherein said clearcoats, when the clearcoats are matt clearcoats, exhibit not only an excellent gloss, but also at the same time a stable gloss, which does not or at least not significantly vary across the different areas and parts of the car body, even when there are variations of the dry layer thicknesses across these areas and parts, e.g., of about 10 pirn or even more.

[0014] Solution

[0015] This objective has been solved by the subject-matter of the claims of the present application as well as by the preferred embodiments thereof disclosed in this specification, i.e. by the subject matter described herein.

[0016] A first subject-matter of the present invention is a clearcoat system comprising at least two components A) and B) and optionally at least one further component C) being different from one another and being separate from each other, wherein component A) comprises at least constituents a1), a2), a3) and optionally constituent a4), which are different from one another, namely 220842W001 1 L023824PCT 3 October 7, 2025

[0017] BASF Coatings GmbH at least one OH-functional polymer as constituent a1), at least two kinds of silica constituents, namely at least one kind of fumed silica as constituent a2), and at least one kind of amorphous silica matting agent as constituent a3), which is different from constituent a2), and optionally at least one organic solvent a4), wherein the weight amount of constituent a3) within component A) exceeds the weight amount of constituent a2), and wherein the amount of constituent a3) in component A) is at least 2.5 wt.-%, based on the total weight of component A), wherein component B) comprises at least constituent b1) and optionally one or more of constituents b2) and b3), which are different from one another, namely at least one organic constituent b1) bearing on average two or more isocyanate groups, wherein at least a part of these isocyanate groups has been reacted with at least one silane prior to incorporation of constituent b1) into component B), optionally at least one organic constituent b2) being different from organic constituent b1) and bearing on average two or more isocyanate groups, wherein none of the isocyanate groups of constituent b2) has been reacted with at least one silane prior to incorporation of constituent b2) into component B), optionally at least one organic solvent b3), and wherein optional component C) is a reducer component and comprises at least one organic solvent d).

[0018] A further subject-matter of the present invention is a clearcoat composition obtainable by mixing at least components A) and B) and optionally C) of the inventive clearcoat system with each other.

[0019] A further subject-matter of the present invention is a method of coating a substrate, comprising at least one step of applying to an optionally pre-coated substrate at least one inventive clearcoat composition to form at least one coating film onto the optionally pre-coated substrate and optionally at least one further step of curing the at least one coating film to obtain at least one cured clearcoat layer onto the substrate.

[0020] A further subject-matter of the present invention is a coated substrate, which is obtainable by the inventive method.

[0021] A further subject-matter of the present invention is a multilayer coating system being present on an optionally precoated substrate and comprising at least two coatings layers L1 and L3 and optionally at least one coating layer L2 being different from one another, namely 220842W001 1 L023824PCT 4 October 7, 2025

[0022] BASF Coatings GmbH a first coating layer L1 applied over at least a portion of an optionally pre-coated substrate, said layer L1, optionally a second coating layer L2 applied over the first coating layer L1 , said layer L2 being, and a third coating layer L3 applied over the first coating layer L1 or, if present, over the second coating layer L2, said layer L3 being obtainable from the inventive clearcoat composition.

[0023] It has been in particular surprisingly found that an excellent gloss can be observed for substrates coated with a matt clearcoat layer, e.g., as outermost layer of a multilayer coating system being present on the substrate, when the clearcoat layer is derived from a clearcoat film, which has been obtained from an inventive clearcoat composition, which in turn has been obtained from an inventive clearcoat system. It has been in particular further surprisingly found that said excellent gloss is observed for a variety of different substrates such as car bodies, in particular in automotive OEM applications, when the aforementioned particularly matt clearcoat layer is present as outermost layer of a multilayer coating system being present on said car bodies.

[0024] Moreover, it has been further surprisingly found that not only an excellent gloss is observed, but at the same time also a stable gloss, which does not or at least not significantly vary across the different areas and parts of the car body used as substrate, even when there are variations of the dry layer thicknesses of at least the clearcoat layer being present across these areas and parts, e.g., of about 10 m or even more. The clearcoat layers thus display a stable and constant gloss over different dry layer thicknesses, in particular in case of matt clearcoats. This is particularly surprising, since in conventional matt clearcoats usually the observed gloss is a function of the dry layer thickness, and that by using the inventive clearcoat system for providing clearcoat layers, this correlation has thus been found to be reduced, by which clearcoats with more stable gloss values over the overall car body could be obtained.

[0025] It has been in particular found that the aforementioned advantages are a result of the presence of at least one kind of a fumed silica a2) such as a hydrophobic fumed silica in combination with the presence of the at least one matting agent constituent a3) in the clearcoat compositions, even if said matting agent is used in an amount of at least 2.5 wt.-%, based on the total amount component A). It has been found that this ensures a sufficient stabilization of the at least one kind of a fumed silica a2) in particular within the clearcoat layer that is obtained after dry ing / curing .

[0026] It has been additionally found that not only an excellent and stable gloss could be observed, but that also other relevant properties such as appearance, a sufficiently minimized or even non-existent whitening after exposure to humidity and / or moisture, and scratch resistance can be achieved at the same time as well. 220842W001 1 L023824PCT 5 October 7, 2025

[0027] BASF Coatings GmbH

[0028] Detailed description of the invention

[0029] The term "comprising" in the context of the present invention, in particular in connection with the coating system, components A) and B) and optionally C) of the coating system, and the coating composition according to the invention preferably has the meaning "consisting of". In this case, in addition to the mandatory constituents present within components A) and B) and C) or the coating composition, one or more of the further optional constituents mentioned hereinafter contained in each of the components of the coating system or coating composition according to the invention may be contained therein, its components A) and B) and optionally C) or in the coating composition according to the invention. All constituents can be present in each case in their preferred embodiments mentioned hereinafter.

[0030] The proportions and amounts in wt.-% (% by weight) of the constituents present within components A) and B) and C) and of further optionally present constituents in the coating system add up to 100 wt.-%, based in each case on the total weight of the respective component A) or B) or C) of the coating system. The same applies to all constituents present in the coating composition: The proportions and amounts in wt.-% (% by weight) of all constituents present add up to 100 wt.-%, based on the total weight of the clearcoat composition according to the invention.

[0031] Coating system (clearcoat system)

[0032] The inventive coating system is a two- (2K-) or multi-component clearcoat system comprising at least two components A) and B) being different from one another and also being separate from each other. Separate from each other in this context means that, for example, components A) and B) of the coating system can be stored separately until they are mixed with each other in order to prepare an inventive clearcoat composition. When the coating system is a multi-component coating system it preferably contains at least one further optional component C), which is different from components A) and B) and also separate from both A) and B). Component C) preferably is a reducer component used for diluting the to-be-prepared coating composition and thus preferably comprises at least one organic solvent d) and more preferably consists of at least one organic solvent d). In case the coating system is a two-component coating system, however, which is preferred, it preferably consists of components A) and B).

[0033] Upon mixing of at least the two components A) and B) a polyurethane or polyurethane-based coating composition is formed by reaction of the OH-groups of constituent a1) with the isocyanate groups of at least constituent b1) and optionally constituent b2).

[0034] Preferably, both components A) and B) and also optional component C) of the inventive coating system are free or essentially free of water. The same applies to the inventive coating compositions. In the sense of the present invention the term "free of water” preferably means that no water at all is present. In the sense of the present 220842W001 1 L023824PCT 6 October 7, 2025

[0035] BASF Coatings GmbH invention the term "essentially free of water” preferably means that essentially no water is present. This means that at least no water is added on purpose to any of the inventively used components A) and B) and optionally C) and to the inventive coating composition. It may, however, not be ruled out that remaining residues of water formed upon preparation of any of the constituents used for preparing the inventively used components A) and B) and optionally C) are present therein. Preferably, the amount of any water present in each of components A) and B) and optionally C) is less than 1 wt.-%, more preferably less than 0.5 wt.-%, even more preferably less than 0.1 wt.- %, still more preferably less than 0.05 wt.-%, yet more preferably less than 0.01 wt.-%, in particular less than 0.005 wt.-% or less than 0.001 wt.-%, in each case based on the total weight of component A) or B) or optionally C).

[0036] Preferably, both components A) and B) and also optional component C) of the coating system are solventborne, i.e. , organic solvent(s)-based. Thus, preferably, the coating system is not a waterborne, i.e. , an aqueous, coating system.

[0037] Preferably, none of components A) and B) and optionally C) of the inventive coating system contains any pigments, in particular any color and / or effect imparting pigments. The same applies, of course, also preferably, to the inventive coating composition.

[0038] Component A)

[0039] Component A), which represents a master batch component, comprises at least constituents a1), a2) and a3), but may additionally comprise further optional constituents.

[0040] Preferably, component A) of the coating system has a total solids content, which is >30 wt.-%, preferably >35 wt- %, more preferably >40 wt.-%, even more preferably >45 wt.-%, based on the total weight of component A). The total solids content of component A) of the coating system is preferably in a range of from >35 to 60 wt.-%, more preferably of from 40 to 58 wt.-%, even more preferably of from 42.5 to 56 wt.-%, in particular of from 45 to 54 wt.- %, based in each case on the total weight of component A). The total solids content, in other words the non-volatile fraction, is determined in accordance with the method described hereinafter.

[0041] Constituent a1)

[0042] Constituent a1) is at least one OH-functional polymer, which functions as film-forming binder. For the purposes of the present invention, the term "binder" is understood in accordance with DIN EN ISO 4618 (German version, date: March 2007) to be the non-volatile constituent of a coating composition, which is responsible for the film formation. Pigments and / or fillers contained therein are thus not subsumed under the term "binder”. Preferably, the at least one OH-functional polymer such as an OH-functional (meth)acrylic copolymer is the main binder of the coating composition. As the main binder in the sense of the present invention, a binder constituent is preferably referred to, when there is no other binder constituent in the coating composition, which is present in a higher proportion based on the total weight of the coating composition. 220842W001 1 L023824PCT 7 October 7, 2025

[0043] BASF Coatings GmbH

[0044] The term "polymer" is known to the person skilled in the art and, for the purposes of the present invention, encompasses polyadducts and polymerizates as well as polycondensates. The term "polymer" includes both homopolymers and copolymers. The term (meth)acrylic polymer hence also includes both homopolymers and copolymers in each case, but preferably means copolymers.

[0045] The at least one OH-functional polymer a1) preferably comprises on average two or more OH-groups. Preferably, the at least one OH-functional polymer a1) has an OH number of 30 to 400 mg KOH / g, more particularly between 100 and 300 KOH / g.

[0046] Preferably, the at least one OH-functional polymer a1) has a weight average molecular weight Mw, measured by means of gel permeation chromatography (GPC) against a polystyrene standard, between 800 and 100 000 g / mol, more particularly between 1000 and 75 000 g / mol.

[0047] Particularly preferred constituents a1) are selected from the group consisting of polyesters, polyurethanes, poly(meth)acrylates and mixtures thereof. As outlined above these terms include both homopolymers and copolymers in each case.

[0048] Suitable polyesters are described for example in EP-A-0 994 117 and EP-A-1 273 640. Polyurethane polyols are prepared preferably by reaction of polyester polyol prepolymers with suitable di- and / or polyisocyanates and are described for example in EP-A-1 273 640.

[0049] Preferably, the at least one OH-functional polymer a1) is at least one OH-functional (meth)acrylic copolymer and / or at least one OH-functional polyester, more preferably at least one OH-functional (meth)acrylic copolymer. Preferably at least two OH-functional (meth)acrylic copolymer are present as constituent a1) in component (A), which are different from one another. If at least two OH-functional (meth)acrylic copolymer are present as constituent a1) in component (A), they differ from each other preferably at least in their glass transition temperature.

[0050] Preferably, at least one OH-functional (meth)acrylic copolymer and / or at least one OH-functional polyester, more preferably at least one OH-functional (meth)acrylic copolymer, even more preferably at least two OH-functional (meth)acrylic copolymers being different from one another and optionally additionally at least one OH-functional polyester, is / are present as the at least one OH-functional polymer a1).

[0051] Preferably, the at least one OH-functional polymer a1) has a glass transition temperature, preferably measured by means of DSC measurements in accordance with DIN EN ISO 11357-2 (2019-03), in a range of from -150 to +100 °C, more preferably of from -120 °C to +80 °C. Tgis measured according to the method disclosed in the 'method' section. 220842W001 1 L023824PCT 8 October 7, 2025

[0052] BASF Coatings GmbH

[0053] Preferably, in particular when at least one OH-functional (meth)acrylic copolymer is used as part of constituent a1) or as constituent a1) as such, it has a glass transition temperature (Tg) being in a range of from -30 °C to +30 °C, preferably of from -20 °C to +25 °C, more preferably of from -10 °C to +20 °C, still more preferably of from 0 °C to +15 °C. As mentioned above, if at least two OH-functional (meth)acrylic copolymers are present as constituent a1) in component (A), they differ from each other preferably at least in their glass transition temperature. Preferably, the first (meth)acrylic copolymer has a glass transition temperature as mentioned above in this paragraph and the second (meth)acrylic copolymer has a lower glass transition temperature, more preferably a glass transition temperature (Tg) being in a range of from -70 °C to +10 °C, preferably of from -50 °C to +5 °C, more preferably of from -40 °C to 0 °C, still more preferably of from -30 °C to -5 °C.

[0054] The term "(meth) acryl" or "(meth) acrylate" or (meth)acrylic” in the context of the present invention in each case comprises the meanings "methacryl" and / or "acryl" "methacrylic" and / or "acrylic" or "methacrylate" and / or "acrylate". Therefore, a "(meth)acrylic copolymer” in general may be formed from only "acrylic monomers”, only "methacrylic monomers” or "acrylic and methacrylic monomers”. However, polymerizable monomers other than acrylic and / or methacrylic monomers as, e.g., styrene and the like may also be contained in a "(meth)acrylic copolymer”. In other words, a (meth)acrylic polymer may consist of only acrylic and / or methacrylic monomer units but does not have to. The notation "(meth)acrylate polymer or copolymer” or "(meth)acrylic polymer or copolymer” is intended to mean that the polymer / copolymer (polymer skeleton / backbone) is formed predominantly, i.e., preferably more than 50% or more than 75% of the monomer units used, from monomers having a (meth)acrylate group. In the preparation of a (meth)acrylic copolymer, preferably more than 50% or 75% of the monomers thus have a (meth)acrylate group. However, the use of further monomers as comonomers such as copolymerizable vinyl monomers, e.g., styrene, for its preparation is not excluded.

[0055] For introduction of OH-functionality, hydroxyl-containing monomers can be used, which include hydroxy alkyl esters of acrylic or methacrylic acid. Non-limiting examples of hydroxyl-functional monomers include hydroxyethyl(meth)acrylate, hydroxypropyl(meth)acrylates, hydroxybutyl-(meth)acrylates, hydroxyhexyl- (meth)acrylates, propylene glycol mono(meth)acrylate, 2,3-dihydroxypropyl(meth)acrylate, pentaerythritol mono(meth)acrylate, polypropylene glycol mono(meth)acrylates, polyethylene glycol mono(meth)acrylates, reaction products of these with epsilon-caprolactone, and other hydroxyalkyl-(meth)acrylates having branched or linear alkyl groups of up to about 10 carbons, and mixtures of these, where the term "(meth)acrylate” indicates either or both of the methacrylate and acrylate esters. Generally, at least about 5 % by weight hydroxyl-functional monomer is preferably included in the polymer. Hydroxyl groups on a vinyl polymer such as an acrylic polymer can be generated by other means, such as, for example, the ring opening of a glycidyl group, for example from copolymerized glycidyl methacrylate, by an organic acid or an amine.

[0056] Hydroxyl functionality may also be introduced through thio-alcohol compounds, including, without limitation, 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-proanediol, 4-mercapto-1- 220842W001 1 L023824PCT 9 October 7, 2025

[0057] BASF Coatings GmbH butanol, and combinations of these. Any of these methods may be used to prepare a useful hydroxyl-functional (meth)acrylic polymer.

[0058] Examples of suitable comonomers that may be used include, without limitation, a,p-ethylenically unsaturated monocarboxylic acids containing 3 to 5 carbon atoms such as acrylic, methacrylic, and crotonic acids and the alkyl and cycloalkyl esters, nitriles, and amides of acrylic acid, methacrylic acid, and crotonic acid; a,p-ethylenically unsaturated dicarboxylic acids containing 4 to 6 carbon atoms and the anhydrides, monoesters, and diesters of those acids; vinyl esters, vinyl ethers, vinyl ketones, and aromatic or heterocyclic aliphatic vinyl compounds. Representative examples of suitable esters of acrylic, methacrylic, and crotonic acids include, without limitation, those esters from 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-butyl cyclohexyl, 4-cyclohexyl-1 -butyl, 2-tert-butyl cyclohexyl, 4-tert-butyl cyclohexyl, 3, 3, 5, 5, -tetramethyl cyclohexyl, tetrahydrofurfuryl, and isobornyl acrylates, methacrylates, and crotonates; unsaturated dialkanoic acids and anhydrides such as fumaric, maleic, itaconic acids and anhydrides and their mono- and diesters with alcohols such as methanol, ethanol, propanol, isopropanol, butanol, isobutanol, and tert-butanol, like maleic anhydride, maleic acid dimethyl ester and maleic acid monohexyl ester; vinyl acetate, vinyl propionate, vinyl ethyl ether, and vinyl ethyl ketone; styrene, a-methyl styrene, vinyl toluene, 2-vinyl pyrrolidone, and p-tert-butylstyrene.

[0059] The (meth)acrylic copolymer may be prepared using conventional techniques, such as by heating the monomers in the presence of a polymerization initiating agent and optionally a chain transfer agent. The polymerization may be carried out in solution, for example. Typical initiators are organic peroxides such as dialkyl peroxides such as di-t-butyl peroxide, peroxyesters such as t-butyl peroxy 2-ethylhexanoate, and t-butyl peracetate, peroxydicarbonates, diacyl peroxides, hydroperoxides such as t-butyl hydroperoxide, and peroxyketals; azo compounds such as 2,2'azobis(2-methylbutanenitrile) and 1,1'-azobis(cyclohexanecarbonitrile); and combinations of these. Typical chain transfer agents are mercaptans such as octyl mercaptan, n- or tert-dodecyl mercaptan; halogenated compounds, thiosalicylic acid, mercaptoacetic acid, mercaptoethanol and the other thiol alcohols already mentioned, and dimeric alpha-methyl styrene. The polymerization reaction is usually carried out at temperatures from about 20 °C to about 200 °C. The reaction may conveniently be done at the temperature at which the solvent or solvent mixture refluxes, although with proper control a temperature below the reflux may be maintained. The initiator should be chosen to match the temperature at which the reaction is carried out, so that the half-life of the initiator at that temperature should preferably be no more than about thirty minutes. Further details of addition polymerization generally and of polymerization of mixtures including (meth)acrylate monomers is readily available in the polymer art. The solvent or solvent mixture is generally heated to the reaction temperature and the monomers and initiator(s) are added at a controlled rate over a period of time, usually between 2 and 6 hours. A chain transfer agent or additional solvent may be fed in also at a controlled rate during this time. The temperature of the mixture is then maintained for a period of time to complete the reaction. Optionally, additional initiator may be added to ensure complete conversion. 220842W001 1 L023824PCT 10 October 7, 2025

[0060] BASF Coatings GmbH

[0061] The (meth)acrylic copolymers that are especially preferred in accordance with the invention for use as constituent a1) preferably have a weight average molecular weight Mwbetween 1 000 and 35 000 g / mol, more preferably between 1 500 and 30 000 g / mol, even more preferably between 1 500 and 25 000 g / mol, still more preferably between 1 500 and 15 000 or 10 000 g / mol, preferably measured in each case by means of gel permeation chromatography (GPC) against a polystyrene standard. These copolymers preferably have an OH number of 60 to 300 mg KOH / g, more particularly between 70 and 200 mg KOH / g, and an acid number of between 0 and 30 mg KOH / g.

[0062] Preferably, the at least one constituent a1), in particular when it is at least one (meth)acrylic polymer, is preferably present in the component A) in an amount in the range of from 5.0 wt.-% to 85.0 wt.-%, based on the total weight of component A). More preferably, the at least one constituent a1) is present in component A) in an amount in the range of from 10.0 wt.-% to 80.0 wt.-%, yet more preferably of from 15.0 wt.-% to 75.0 wt.-%, even more preferably of from 20.0 wt.-% to 70.0 wt.-%, still more preferably of from 25.0 to 65.0 wt.-%, most preferably of from 30.0 to 60.0 wt.-%, in each case based on the total weight of component A).

[0063] Constituent a2)

[0064] The at least one kind of silica of fumed silica used as constituent a2) is preferably selected from the group consisting of hydrophilic and hydrophobic fumed silica and mixtures thereof, more preferably is selected from the group consisting of hydrophobic fumed silica.

[0065] Preferably, constituent a2) is present in component A) in an amount in the range of from 0.10 to 10.0 wt.-%, more preferably of from 0.20 to 8.0 wt.-%, still more preferably of from 0.30 to 7.0 wt.-%, even more preferably of from 0.40 to 5.0 wt.-%, still more preferably of from 0.50 to 4.0 wt.-%, yet more preferably of from 0.75 to 3.0 wt.-%, based in each case on the total weight of component A).

[0066] Fumed silica for use as constituent a2) is, e.g., disclosed in WO 2014 / 086530 A1.

[0067] Preferably, the fumed silica for use as constituent a) has a chainlike structure and is an agglomerate and / or or aggregate of silicon dioxide primary particles. Preferably, constituent a2) is pyrogenic fumed silica. Constituent a2) is particularly obtainable by flame hydrolysis of silicon halogen compounds. Fumed silica of this kind is available commercially, for example, under the Aerosil® designation from Evonik Degussa.

[0068] As the skilled person is aware, through suitable reaction conditions during the flame hydrolysis and surface modifications to the primary silicon dioxide particles, it is possible to vary the parameters and hence also the properties of the fumed silica particles in a controlled way. For example, a part is played by the primary particle size of the silicon dioxide particles, since in general the tendency to form agglomerates goes down as the primary particle size goes up. Furthermore, of course, a small primary particle size implies a high specific surface area. 220842W001 1 L023824PCT 11 October 7, 2025

[0069] BASF Coatings GmbH

[0070] Moreover, a distinction is made in particular between hydrophilic silica and hydrophobic silica. It is possible to use either hydrophilic silica or hydrophobic silica, or a mixture of hydrophilic silica and hydrophobic silica.

[0071] The fumed silica produced by means of flame hydrolysis has various functional groups on its surface, especially silanol groups and / or siloxane groups. It is therefore hydrophilic as such and can be used without further modification to its surface.

[0072] It is also possible to use fumed silica whose surface has been modified with monomeric and / or oligomeric compounds. Surface modification is typically accomplished by attachment of the groups located on the silica surface, such as silanol groups, for example, to monomeric and / or oligomeric compounds. These monomeric or oligomeric compounds therefore contain at least one group which has an affinity for the groups located on the particle surface. The attachment may be accomplished, for example, by covalent bonding, ionic attachment and / or physisorption. The part of the monomeric and / or oligomeric compounds that is not needed for attachment to the silica particle surface protrudes preferably wholly or partly into the medium surrounding the particles. The monomeric and / or oligomeric compounds that are used for surface modification may contain further functional groups in addition to the group required for attachment to the surface of the silica particles, these further functional groups being able, for example, to react with constituent a1) and / or b1). A surface modification of this kind is accomplished for example by addition of hydrolyzable silanes which further carry at least one additional functional group to the silica particles.

[0073] Examples of hydrolyzable silanes suitable for the surface modification of the particles include those silanes which, as a group reactive toward constituent a1) and / or toward b1), comprise a glycidyl group, an amino group, a hydroxyl group and / or a mercapto group.

[0074] For surface modification, however, it is possible in accordance with the invention to use monomeric and / or oligomeric compounds which as well as the group that is reactive toward silanol groups have one or more hydrophobic radicals and so are associated with a hydrophobicizing of the silica particles and therefore serve to produce the hydrophobic silica. For modifying the silica it is preferred to use organofunctional silicon compounds having at least one alkyl group with 1 to 50 carbon atoms, more particularly with 1 to 10 carbon atoms, and with at least one hydrolyzable group, and / or with at least one hydroxyl and / or amino group. Examples of such compounds are alkylalkoxysilanes, more particularly dialkyldialkoxysilanes and alkyltrialkoxysilanes, alkylhalosilanes, more particularly alkylchlorosilanes, preferably trialkylchlorosilanes and dialkyldichlorosilanes, alkylpolysiloxanes, dialkylpolysiloxanes, and alkyldisilazanes and the like. Octamethylcyclotetrasiloxane may be in particular used.

[0075] As hydrophobic silica it is particularly preferred here to use silanized, pyrogenically prepared silicas which have monomethylsilyl groups and / or dimethylsilyl groups and / or trimethylsilyl groups fixed on the surface. These can be prepared for example by surface-modifying a pyrogenically prepared silicon dioxide with trimethylchlorosilane and / or dimethyldichlorosilane and / or monomethyltrichlorosilane. 220842W001 1 L023824PCT 12 October 7, 2025

[0076] BASF Coatings GmbH

[0077] Preferably, constituent a2) has an average primary particle size of <50 nm, more preferably of <30 nm, even more preferably of <20 nm, still more preferably of <15 nm, most preferably of <10 nm.

[0078] Preferably, constituent a2) has an internal BET surface area of more than 100 m2 / g, more particularly have an internal BET surface area of more than 200 m2 / g, wherein more preferably, in particular in case of hydrophobic silica, the BET surface area does not exceed 300 m2 / g. In case of hydrophilic fumed silica, internal BET surface area is preferably >300 m2 / g.

[0079] Preferably, constituent a2), when present in an aqueous suspension containing 5 wt.-% of constituent a2), has a pH value of >3.0, more preferably of >3.5, even more preferably of >3.7.

[0080] Preferably, the average particle size (median) of constituent a2) exceeds the average particle size (median) of constituent a3), more preferably by at least 20%, even more preferably by at least 30%, still more preferably by at least 50%.

[0081] Preferably, the average particle size (median) of constituent a2) is in a range of from 4.0 to 200.0 pm, more preferably of from 10.0 to 150.0 pm, more preferably of from 20.0 to 100.0 pm, still more preferably of from 35.0 to 80.0 pm, yet more preferably of from 45.0 to 70 pm. The average particle size is determined according to the method disclosed in the ‘methods' section.

[0082] Examples of hydrophilic silica are also the customary and known products which are available commercially and are sold, for example, by Degussa Evonik under the brand name Aerosil® 380, Aerosil® 300, Aerosil® 200, Aerosil® 150 and Aerosil® 130, or by Wacker under the type designation T 40, with Aerosil® 380 being used in particular.

[0083] Examples of hydrophobic silica are customary and known products as sold, for example, by Degussa Evonik under the brand name Aerosil®, more particularly Aerosil® R816, R711, 8200, R106, R972, R974, R805, R812, or R812S, or by Wacker under the brand name or type designation HDK, more particularly HDK H 15, H 18, H 20, H 30 or 2000, with Aerosil® R106 and / or R812 being used in particular.

[0084] Constituent a2) is incorporated into component A) preferably by making use of a dispersion and / or solution of at least one polymer such as at least part of the at least one constituent a1) in at least one organic solvent such as at least one organic solvent a4).

[0085] The use of hydrophobic silica as constituent a2) is particularly preferred. 220842W001 1 L023824PCT 13 October 7, 2025

[0086] BASF Coatings GmbH

[0087] Constituent a3)

[0088] Constituent a3) is at least one kind of amorphous silica matting agent, which) is different from any of constituents a1) and a2) and optional constituent a4). The weight amount of constituent a3) exceeds the weight amount of constituent a2), and the amount of constituent a3) in component A) is at least 2.5 wt.-%, based on the total weight of component A).

[0089] The term "matting agent” is known to a person skilled in the art, e.g., from "Rbmpp Lexikon, Lacke und Druckfarben, Thieme Verlag 1998, 10. Auflage, page 372: a matting agent can be used to make a paint finish appear less glossy and / or to create a matt gloss.

[0090] Preferably, the amount of constituent a3) in component A) is at least 3.0 wt.-%, more preferably at least 3.5 wt.-%, yet more preferably at least 4.0 wt.-%, even more preferably at least 4.5 wt.-%, still more preferably at least 5.0 wt.- %, yet more preferably at least 5.5 wt.-%, even more preferably at least 6.0 wt.-%, still more preferably at least 6.5 wt.-%, most preferably at least 7.0 wt.-%, in each case based on the total weight of component A).

[0091] Preferably, the maximum amount of constituent a3) in component A) is 25.0 wt.-%, more preferably 20.0 wt.-%, yet more preferably 15.0 wt.-%, most preferably 10.0 wt.-%, in each case based on the total weight of component A).

[0092] Preferably, constituent a3), when present in an aqueous suspension containing 5 wt.-% of constituent a3), has a pH value of >3.0, more preferably of >3.25, even more preferably of >3.5.

[0093] Preferably, constituent a3) has a pore volume of at least 1.0 mL / g, more preferably of at least 1 .5 mL / g, prior to any optional surface treatment performed.

[0094] Preferably, at least one kind of synthetic amorphous silica matting agent is used as constituent a3).

[0095] Preferably, constituent a3) has an average particle size (median) in a range of from 1 .0 to 20.0 pm, more preferably of from 2.0 to 15.0 pm, even more preferably of from 3.0 to 10.0 pm, still more preferably of from 4.0 to 8.0 pm, yet more preferably of from 5.0 to 7.0 pm. The average particle size is determined according to the method disclosed in the ‘methods' section.

[0096] Preferably, the average particle size (median) of constituent a3) differs from the average particle size (median) of constituent a2). Preferably, the aforementioned average particle size of constituent a3) is lower than the aforementioned average particle size of constituent a2), more preferably by at least 20%, even more preferably by at least 30%, still more preferably by at least 50%.

[0097] Preferably, constituent a3) is a surface treated silica matting agent, wherein at least one organic compound has been used for said surface treatment. 220842W001 1 L023824PCT 14 October 7, 2025

[0098] BASF Coatings GmbH

[0099] Preferably, the relative weight ratio of constituents a3) and a2) to each other is in a range of from 100.0:1.0 to 1.1 : 1.0, more preferably of from 80.0:1.0 to 1.5: 1.0, still more preferably of from 50.0:1.0 to 2.0: 1.0, yet more preferably of from 40.0: 1.0 to 3.0: 1.0, still more preferably of from 30.0:1.0 to 4.0: 1.0, even more preferably of from 20.0: 1.0 to 5.0: 1.0, yet more preferably of from 15.0:1.0 to 6.0:1.0, most preferably of from 10.0:1.0 to 6.5: 1.0.

[0100] Optional constituent a4)

[0101] Optional constituent a4) is at least one organic solvent, preferably at least one aprotic organic solvent, i.e., solvents not being proton donators and thus being chemically inert towards a reaction with NCO groups. Examples of such organic solvents include heterocyclic, aliphatic, or aromatic hydrocarbons, mono- or polyhydric alcohols, especially methanol and / or ethanol, ethers, esters, ketones, and amides, such as, for example, N-methylpyrrolidone, N- ethylpyrrolidone, dimethylformamide, toluene, xylene, butanol, ethyl glycol, propyl glycol, and butyl glycol and also their acetates, butyl diglycol, diethylene glycol dimethyl ether, cyclohexanone, methyl ethyl ketone, methyl isobutyl ketone, acetone, isophorone, or mixtures thereof. Component A) may comprise more than one organic solvent as constituent a4). The at least one organic solvent a4) may the identical to or different from the at least one organic solvent b3) and / or d). If more than one organic solvent is used as a4) and / or b3) and / or d) it may be that a4) and b3) and / or d) 3 are both partially identical and partially different.

[0102] Preferably, the amount of constituent a4) in component (A), if present, is in a range of from 10 to 70 wt.-%, more preferably of from 15 to 65 wt.-%, based in each case on the total weight of component A).

[0103] Optional constituent a5)

[0104] Optionally, at least one urea moiety or urea moieties containing constituent a5) may be present, which preferably is selected from adducts of at least at least one diisocyanate and / or at least one polyisocyanate and at least one preferably primary or secondary amine, wherein such adducts optionally are prepared in the presence of at least one OH-functional polymer, which can be identical to or different from the at least one OH-functional polymer constituent a1).

[0105] Preferably, constituent a5) is present in an amount in the range of from 0.10 to 10.0 wt.-%, more preferably of from 0.10 to 8.0 wt.-%, even more preferably in an amount in the range of from 0.10 to 7.0 wt.-%, yet more preferably of from 0.10 to 5.0 wt.-%, still more preferably of from 0.10 to 4.0 wt.-%, yet more preferably of from 0.10 to 3.0 wt.- %, still more preferably of from 0.10 to 2.0 wt.-%, in particular of from 0.10 to 1.5 wt.-%, most preferably of from 0.10 to 1.0 wt.-%, in each case based on the total weight of component A). Alternatively and also preferably, constituent a5) is present in an amount in the range of from 0.20 to 8.0 wt.-%, based on the total weight of component A), more preferably in an amount in the range of from 0.20 to 7.0 wt.-%, even more preferably of from 0.20 to 5.0 wt.-%, still more preferably of from 0.20 to 4.0 wt.-%, yet more preferably of from 0.20 to 3.0 wt.-%, still more preferably of from 0.20 to 2.0 wt.-%, in particular of from 0.20 to 1.5 wt.-%, most preferably of from 0.20 to 1 .0 wt.-%, in each case based on the total weight of component A). 220842W001 1 L023824PCT 15 October 7, 2025

[0106] BASF Coatings GmbH

[0107] Particularly suitable primary or secondary amines for the preparation of adducts (I) are monoamines. The adducts preferably, if present, are present in a crystalline form, e.g., in the form of urea crystals.

[0108] Said adduct is preferably physically and / or chemically associated with at least one OH-functional polymer, which may be identical to polymer constituent a1) or different therefrom. Preferably, saod adduct is prepared by adding the at least one diisocyanate and / or the at least one polyisocyanate, preferably the at least one diisocyanate, to a mixture of the at least one primary or secondary amine, in particular monoamine, in the presence of at least one OH-functional polymer, preferably of at least one OH-functional (meth)acrylic copolymer, which can be identical to or different from the at least one OH-functional polymer constituent a1). The OH-functional polymer may function as sag control polymer or resin and as a moderating resin, which is preferably present during the reaction of the isocyanate and the amine. In case the urea formation takes place in the presence of such a polymer, part of the formed urea might not only be physically associated, but also partially chemically associated with the polymer, e.g., by urethan formation as a side reaction between hydroxyl groups of the resin and isocyanate groups of the diisocyanate and / or polyisocyanate.

[0109] Urea moiety or moieties containing adducts may function as sag control agent (SCA). Such urea moiety or moieties containing constituents are, e.g., disclosed in WO 2013 / 076208 A1 and WO 2012 / 140131 A1.

[0110] Preferably, no other starting material besides the at least one diisocyanate and / or polyisocyanate and the at least one amine such as monoamine is used for preparing urea moiety or moieties containing said adduct. However, as outlined hereinbefore, it is also possible that the adduct is prepared by additionally making use of an OH-functional polymer such as at least part of constituent a1). For example, a constituent a5) may be prepared by reaction of the amine such as monoamine with the diisocyanate and / or polyisocyanate under formation of urea bonds, which still bears NCO-groups. These may then further react with the above mentioned OH-functional polymer.

[0111] In particular, the adduct is prepared by adding the at least one diisocyanate and / or polyisocyanate, preferably the at least one diisocyanate, to a mixture of the at least one amine such as monoamine in the presence of at least one OH-functional polymer, preferably of at least one OH-functional (meth)acrylic copolymer, which can be identical to or different from the at least one OH-functional polymer a1). Thereby an adduct bearing both at least one urea and at least one urethane moiety is formed.

[0112] Preferably, urea moiety or moieties containing constituent adduct does not contain any free NCO-groups, in particular no remaining free NCO-groups due to using the diisocyanate and / or polyisocyanate for its preparation. Alternatively, such NCO-groups may still be present, which will then react with the OH-groups of at least constituent a1) under formation of additionally present urethane bonds within a5).

[0113] Polyisocyanates, which can be used in principle for preparing the adducts as constituent a5), are organic 220842W001 1 L023824PCT 16 October 7, 2025

[0114] BASF Coatings GmbH monomers, oligomers and polymers containing two or more isocyanate groups per molecule. Diisocyanates, which can be used in principle for preparing constituent a5), are organic monomers, oligomers and polymers containing precisely two or isocyanate groups per molecule. The diisocyanates and / or polyisocyanates which can be used are preferably selected from those as disclosed and named hereinafter in connection with constituent b2) contained in the hardener component B). It is also possible to use reaction products as diisocyanates and / or polyisocyanates, which contain isocyanate groups and are in turn the products of reaction of for example, polyols and polyamines and polyisocyanates. The diisocyanates and / or polyisocyanates can be aliphatic including cycloaliphatic or aromatic. Preference is given to using diisocyanates, very specifically aliphatic diisocyanates, more particularly hexamethylene diisocyanate. The following are mentioned as examples of polyisocyanates and / or diisocyanates that can be used: tetramethylene 1 ,4-diisocyanate, hexamethylene 1 ,6-diisocyanate, cyclohexyl 1 ,4-diisocyanate, dicyclohexylmethane 4, 4-diisocy anate, 1 ,5-dimethyl-(2,4-omega-diisocyanatomethyl)benzene, 1 , 5-dimethy l-(2, 4- omega-diisocyanato-ethyl)benzene, 1 ,3,5-trimethyl-(2,4-omega-diisocyanatomethyl)benzene, 1 ,3,5-triethy l-(2,4- omega-diisocyanatomethyl)benzene, the trimer of hexamethylene 1 ,6-diisocyanate, isophorone diisocyanate, 2,4- toluene diisocyanate and / or 2,6-toluene diisocyanate.

[0115] Monoamines, which can be used in principle for preparing adducts as constituent a5), are organic monomers, oligomers and polymers containing precisely one amino group per molecule. The amines can be selected from primary amines, secondary amines, diamines, ketamines, aldimines or combinations thereof. The amines are preferably amine monomers. Most preferably, the amines are primary amines, even more preferred primary monoamines. The amino group is preferably a primary or secondary, more preferably a primary amino group. The monoamine can be aliphatic including cycloaliphatic or aromatic. Examples of primary amines include benzyl amine, ethyl amine, n-propylamine, 2-propylamine, 1 -butylamine, 2-butylamine, t-butylamine, n-pentylamine, a- methylbutylamine, o-ethylpropylamine, p-ethylbutylamine, 1-hexylamine, 2-hexylamine, 3-hexylamine, octylamine, decylamine, laurylamine, stearylamine, cyclohexylamine, and aniline. Most preferred the amine is benzyl amine. Other suitable primary amines include alkyl ether amines, such as, for example, 2-aminoethanol alkyl ether, 3- aminopropanol alkyl ether, and 2-ami nopropanol alkyl ether. Examples of secondary amines can include, for example, the N-alkyl derivatives of any of the primary amines listed above wherein alkyl means an alkyl radical having in the range of from 1 to 10 carbon atoms. Examples of diamines can include, aliphatic and cycloaliphatic diamines such as, for example, ethylene diamine, 1 ,2-propylenediamine, 1 ,3-diaminopropane, 1 ,4-butanediamine, neopentanediamine, 4,4-diaminodicyclohexylmethane, isophoronediamine, hexamethylenediamine, 1 ,12- dodecanediamine, piperazine, polyether diamines, polytrimethylene ether diamine or a combination thereof. Examples of preferred monoamines are ethylamine, 1-propyamine, 2-propylamine, 1-butylamine, 2-buty amine, benzylamine and methoxypropylamine. Most preferred are benzylamine or methoxypropylamine.

[0116] Preferably, the at least one amine, more preferably monoamine, is used in an amount for preparing the adduct as constituent a5) that ensures that all isocyanate groups of the polyisocyanates and / or diisocyanates used are converted to urea groups. In this case the adduct is formed only from making use of the polyisocyanate and / or diisocyanate and the amine such as monoamine. 220842W001 1 L023824PCT 17 October 7, 2025

[0117] BASF Coatings GmbH

[0118] The adduct as constituent a5) is preferably prepared in the form of a paste containing at least one organic solvent such as at least one organic solvent a4) and also at least one polymer such as an OH-functional polymer such as at least one part of the at least one OH-functional polymer a1). This paste may then be used for preparation of component A). Thus, constituent a5) may be prepared, for example, directly in the presence of at least one polymer such as an OH-functional polymer such as at least one part of the at least one OH-functional polymer a1). In this case, the procedure for preparing the paste, for example, is to add the amine such as monoamine such as methoxypropylamine or benzylamine to a solution or dispersion of at least one polymer such as an OH-functional polymer such as at least one part of the at least one OH-functional polymer a1) in at least one organic solvent or in a mixture of organic solvents such as at least one organic solvent a4), and then to add the polyisocyanate and / or diisocyanate. In such a case there may be also, for example, as already outlined hereinbefore occurring a linking of the polyisocyanate and / or diisocyanate and / or of a precursor of constituent a5) still containing isocyanate groups, with the at least one OH-functional polymer.

[0119] Urea moiety or moieties containing constituent a5) as adduct of a polyisocyanate and / or diisocyanate and methoxypropylamine in the form of mixtures with OH-functional polymers are available, for example, as commercial products of the company Allnex. An example is Setalux® 81753 SS-55. Urea moiety or moieties containing constituent a5) as adduct of a polyisocyanate and / or diisocyanate and benzylamine in the form of mixtures with OH-functional polymers are also available, for example, as commercial products of the company Allnex. An example is Setalux® 91756 VS-60.

[0120] Optional constituent a6)

[0121] Preferably, component A) further comprises at least one catalyst as optional constituent a6).

[0122] Preferably, component A) of the clearcoat system comprises the at least one catalyst a6) in an amount in a range of from 0.01 to 6.00 wt.-%, preferably of from 0.05 to 5.00 wt.-%, more preferably of from 0.10 to 4.00 wt.-%, still more preferably of from 0.15 to 3.00 wt.-%, yet more preferably of from 0.20 to 2.00 wt.-%, most preferably of from 0.30 to 1 .50 wt.-%, based on the total weight of component A).

[0123] The catalyst a6) can be a catalyst suitable for crosslinking of silane groups, more preferably for the crosslinking of the silane groups and / or Si-functional groups present within constituent b1).

[0124] Examples of constituent a6) are metal complexes with chelate ligands based on zinc or aluminum, such as Lewis acids or the titanates described in WO 05 / 03340 A1 , for example. Other examples include phosphorus-containing, more particularly phosphorus-containing and nitrogen-containing, catalysts for use as catalyst a6). Examples of suitable phosphorus-containing catalysts are substituted phosphonic diesters and diphosphonic diesters, preferably selected from the group consisting of acyclic phosphonic diesters, cyclic phosphonic diesters, acyclic diphosphonic diesters and cyclic diphosphonic diesters. More particularly, however, use as at least one catalyst a6) is made of 220842W001 1 L023824PCT 18 October 7, 2025

[0125] BASF Coatings GmbH substituted phosphoric monoesters and phosphoric diesters, preferably selected from the group consisting of acyclic phosphoric diesters and monoesters and cyclic phosphoric diesters and monoesters, which may be in each case amine adducts, e.g., of phosphoric monoesters and diesters. Examples of such amine adducts are corresponding amine-blocked phosphoric esters, and, of these, more particularly, amine-blocked ethylhexyl phosphates and amine-blocked phenyl phosphates, very preferably amine-blocked bis(2-ethylhexyl) phosphate. Examples of amines with which the phosphoric esters are blocked are, in particular, tertiary amines, examples being bicyclic amines, such as diazabicyclooctane (DABCO), diazabicyclononene (DBN), diazabicycloundecene (DBU), dimethyldodecylamine or triethylamine, for example. Particularly preferred for blocking the phosphoric esters is the use of tertiary amines which ensure high activity of the catalyst under the curing conditions. Certain amine-blocked phosphoric acid catalysts are also available commercially (e.g., Nacure types from King Industries such as Nacure® 4167).

[0126] Alternatively, at least one sulfonic acid such as an unblocked sulfonic acid or a blocked sulfonic acid, more preferably at least one unblocked sulfonic acid, may be used as catalyst a6). Examples of unblocked sulfonic acids are para-toluenesulfonic acid (pTSA), methanesulfonic acid (MSA), dodecylbenzene sulfonic acid (DDBSA), dinonylnaphthalene disulfonic acid (DNNDSA), and mixtures thereof. Blocking can be performed by making use of ammonium salts and / or organic amines. Alternatively, blocking may also be performed by making use of epoxides that form p-OH-sulfonates when reversibly reacted with sulfonic acids.

[0127] Most preferably, catalyst a6) is a phosphorus-containing catalyst.

[0128] Optional constituent a7)

[0129] Component (A) may comprise - besides the at least one OH-functional polymer a1) -at least one further polymer as constituent a7), which may also function as binder, and which is different from OH-functional polymer a1), such as a OH-functional polyester.

[0130] Constituent a7) preferably comprises crosslinkable groups, more preferably selected from the group consisting of hydroxyl groups, primary amino groups, secondary amino groups, thiol groups, carboxyl groups and carbamate groups. Preferably, an optionally present constituent a7) has, e.g., carbamate groups. Optional constituent a7) may be, e.g., a carbamate-functional (meth)acrylic copolymer and / or a polyester that may additionally comprise OH- groups. Likewise, e.g., polyethers and / or polyurethanes may also be used as a7).

[0131] Optional constituent a8)

[0132] Component A) can optionally comprise one or more further constituents as a8). Component A) may contain one or more commonly used additives depending on the desired application. For example, it may comprise at least one additive selected from the group consisting of reactive diluents, light stabilizers, antioxidants, deaerators, emulsifiers, slip additives, polymerization inhibitors, plasticizers, initiators for free-radical polymerizations, adhesion promoters, flow control agents, film-forming auxiliaries, flame retardants, corrosion inhibitors, siccatives, biocides, 220842W001 1 L023824PCT 19 October 7, 2025

[0133] BASF Coatings GmbH thickeners, wetting agents, levelling agents and / or matting agents. They can be used in the known and customary proportions. Preferably, their content, based on the total weight of the coating composition obtained from mixing components A) and B) and optionally C) is 0.01 to 20.0 wt.-%, more preferably 0.05 to 15.0 wt.-%, particularly preferably 0.1 to 10.0 % by weight, even more preferably from 0.1 to 7.5% by weight, especially from 0.1 to 5.0% by weight and most preferably from 0.1 to 2.5% by weight, in each case based on the total weight of the coating composition.

[0134] Optional constituent a9)

[0135] Optionally, component A) further comprises at least one melamine resin, more preferably at least one melamine aldehyde resin, even more preferably at least one melamine formaldehyde resin as optional constituent a9).

[0136] Preferably, the melamine aldehyde resins, more preferably the melamine formaldehyde resins, in each case bear at least one of imino groups, alkykol groups and etherified alkylol groups as functional groups. Examples of alkylol groups are methylol groups.

[0137] At least some of the alkylol groups present in the melamine aldehyde resins may be alkylated through further reaction with at least one alcohol to produce nitrogen-bonded alkoxyalkyl groups (etherified alkylol groups). In particular, the hydroxyl groups in the nitrogen-bonded alkylol groups may be reacted with the alcohol through an etherification reaction to produce nitrogen-bonded alkoxyalkyl groups. The alkoxyalkyl groups are available for a crosslinking reaction with, for example, suitable crosslinkable functional groups such as OH- and / or acid groups. The remaining imino groups present after the aldehyde / melamine reaction are unreactive with the alcohol used for alkylation. As outlined above the alkylol groups of the melamine aldehyde resins may be partially alkylated. By "partially alkylated”, it is meant that a sufficiently low amount of alcohol is reacted with the melamine aldehyde resins to leave some of the alkylol groups in the melamine aldehyde resins, under reaction conditions that should result in incomplete alkylation of the alkylol groups. When the melamine aldehyde resins are partially alkylated, they are typically alkylated with alcohol in amounts sufficient to leave alkylol groups present in the aminoplast in an amount of at least about 2%, more preferably of from about 10% to about 50%, even more preferably of from about 15% to about 40%, in each case based on the total number of reactive sites present in the melamine prior to reaction. Typically, the melamine aldehyde resin is partially alkylated to obtain from about 40 to about 98% of alkoxyalkyl groups, more preferably of from about 50% to about 90%, even more preferably of from about 60% to about 75%, in each case based on the total number of reactive sites present in the melamine prior to reaction.

[0138] Preferably, at least a portion, more preferably only a portion, of the alkylol groups such as methylol groups of the melamine aldehyde resin is etherified by reaction with at least one alcohol. Any monohydric alcohol can be employed for this purpose, including methanol, ethanol, n-propanol, iso-propanol, n-butanol, sec-butanol, t-butanol, pentanol, hexanol, heptanol, as well as benzyl alcohol and other aromatic alcohols, cyclic alcohols such as cyclohexanol, monoethers of glycols, and halogen-substituted or other substituted alcohols such as 3- 220842W001 1 L023824PCT 20 October 7, 2025

[0139] BASF Coatings GmbH chloropropanol and butoxyethanol. In particular, at least a part of the alkylol groups of the melamine aldehyde resin is partially modified with methanol and / or n-butanol and / or iso-butanol.

[0140] Preferably, component A) of the clearcoat system comprises the at least one constituent a9), if present, in an amount in a range of from 0.1 to 20.0 wt.-%, preferably of from 0.5 to 15.0 wt.-%, more preferably of from 1.0 to 10.0 wt.-%, based on the total weight of component A).

[0141] Optional constituent a 10)

[0142] Optionally, component A) further comprises at least one blocked polyisocyanate as constituent a10), which is different from each of constituents a1) to a9) described herein.

[0143] The term "blocked polyisocyanate” is known to the skilled person. In general all kind of blocked polyisocyanates can be used.

[0144] The term "blocked polyisocyanates” is known to the skilled person. Blocked polyisocyanates, which can be utilized, are polyisocyanates having at least two isocyanate groups (diisocyanates in case of precisely two isocyanate groups), but preferably having more than two, such as, for example, 3 to 5 isocyanate groups, wherein the isocyanate groups have been reacted prior to the incorporation of the blocked polyisocyanate into component A), so that the blocked polyisocyanate formed is stable in particular with respect towards a reaction with hydroxyl groups and / or amino groups such as primary and / or secondary amino groups at room temperature, i.e., at a temperature of 18 to 23°C, but at elevated temperatures, as for example at > 80°C, > 110°C, > 130°C, > 140°C, > 150°C, > 160°C, > 170°C, or > 180°, reacts with conversion and with formation of urethane and / or urea bonds, respectively.

[0145] In the preparation of the blocked polyisocyanates it is possible to use any desired organic polyisocyanates suitable for crosslinking. Isocyanates used preferably are (hetero)aliphatic, (hetero)cycloaliphatic, (hetero)aromatic or (hetero)aliphatic-(hetero)aromatic isocyanates. Preferred polyisocyanates are those containing 2 to 36, especially 6 to 15, carbon atoms. Preferred examples are ethylene 1 ,2-ethylene diisocyanate, tetramethylene 1 ,4- diisocyanate, hexamethylene 1 ,6-diisocyanate (HDI), 2,2,4(2,4,4)-tri-methylhexamethylene 1 ,6-diisocyanate (TMDI), diphenylmethane diisocyanate (MDI), 1 ,9-diisocyanato-5-methylnonane, 1 ,8-diisocyanato-2,4-dimethyl- octane, dodecane 1 , 12-diisocyanate, co.co'-diisocyanatodipropyl ether, cyclobutene 1 ,3-diisocyanate, cyclohexane 1 ,3- and 1 ,4-diisocyanate, 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (isophorone diisocyanate, I PD I), 1 ,4-diisocyanatomethyl-2,3,5,6-tetramethyl-cyclohexane, decahydro-8-methyl(1 ,4-methanonaphthalen-2 (or 3), 5-ylenedimethylene diisocyanate, hexahydro-4, 7-methanoindan-1 (or 2), 5 (or 6)-ylenedimethylene diisocyanate, hexahydro-4, 7-methanoindan-1 (or 2), 5 (or 6)-ylene diisocyanate, hexahydrotolylene 2,4- and / or 2,6-diisocyanate (H6-TDI), toluene 2,4- and / or 2,6-diisocyanate (TDI), perhydrodiphenylmethane 2,4'-diisocyanate, perhydrodiphenylmethane 4,4'-diisocyanate (H12MDI), 4,4'-diisocyanato-3,3',5,5'-tetramethyldicyclohexylmethane, 4, 4'-d I isocy an ato-2, 2', 3, 3', 5, 5', 6, 6'-octamethy I d icy clohexy I meth ane, co, oo'-diisocy anato- 1 ,4-diethy I benzene, 1 ,4-di- 220842W001 1 L023824PCT 21 October 7, 2025

[0146] BASF Coatings GmbH isocyanatomethyl-2,3,5,6-tetramethylbenzene, 2-methy I- 1 ,5-diisocyanatopentane (MPDI), 2-ethy I- 1 ,4-diiso- cyanatobutane, 1 ,10-diisocyanatodecane, 1 ,5-diisocyanatohexane, 1 ,3-diisocyanatomethylcyclohexane, 1 ,4-diiso- cyanatomethylcyclohexane, 2,5(2,6)-bis(isocyanatomethyl)bicyclo[2.2.1]heptane (NBDI), and also any mixture of these compounds. Polyisocyanates of higher isocyanate functionality may also be used. Examples thereof are trimerized hexamethylene diisocyanate and trimerized isophorone diisocyanate, more particularly the corresponding isocyanurates. It is also possible, furthermore, to utilize mixtures of polyisocyanates. The same kind of polyisocyanates and / or diisocyanates, preferably polyisocyanates, more preferably polyisocyanates having on average two or more isocyanate groups, can be used, which have been named in connection with the preparation of optional constituent a5). Preferably, however, aliphatic polyisocyanates are used, in particular isocyanurates such as isocyanurates of HDI and / or IPDI, more preferably of HDI.

[0147] For the blocking of the polyisocyanates it is possible with preference to use any desired suitable aliphatic, cycloaliphatic, and / or aromatic alkyl monoalcohols. Examples thereof are aliphatic alcohols, such as methyl, ethyl, chloroethyl, propyl, butyl, amyl, hexyl, heptyl, octyl, nonyl, 3,3,5-trimethylhexyl, decyl, and lauryl alcohol; cycloaliphatic alcohols, such as cyclopentanol and cyclohexanol; and aromatic alkyl alcohols, such as phenylcarbinol and methylphenylcarbinol. Likewise, suitable diols such as ethanediol 1 ,2-propanediol, 1 ,3- propanediol and / or polyols may also be used for blocking of the polyisocyanates. Other suitable blocking agents are hydroxylamines, such as ethanolamine, oximes, such as methyl ethyl ketone oxime, acetone oxime, and cyclohexanone oxime, and amines, such as dibutylamine and diisopropylamine, and AMP (aminomethyl propanol) and / or DMP (dimethyl pyrazol) as an example of an aromatic amine. As amines in general the same kind of amines can be used, which have been named in connection with the preparation of optional constituent a5).

[0148] Hence, preferably, the blocked polyisocyanate constituents a10) contain one or more urea and / or urethane bond(s) due to having used at least one blocking agent for blocking of the NCO-groups.

[0149] Preferably, constituent a10) is present in component A) in an amount in the range of from 1.0 to 35.0 wt.-%, more preferably of from 2.0 to 30.0 wt.-%, still more preferably of from 3.0 to 27.5 wt.-%, even more preferably of from 4.0 to 25.0 wt.-%, still more preferably of from 5.0 to 22.5 wt.-%, yet more preferably of from 7.5 to 20.0 wt.-%, based in each case on the total weight of component A).

[0150] Preferably, the relative weight ratio of constituents a10), if present, and a2) to each other within component A) is >10.0: 1.0 or is >10.1 : 1.0, more preferably is >10.2: 1.0, still more preferably is >10.5:1.0, even more preferably is >11.0: 1.0, still more preferably is >12.0: 1.0, yet more preferably is >13.5:1.0, most preferably is >15.0:1.0.

[0151] Preferably, the relative weight ratio of constituents a10), if present, and a2) to each other is in a range of from >10.0: 1.0 to 100:1.0, more preferably of from >10.1 : 1.0 to 90: 1.0, still more preferably of from >10.5:1.0 to 75: 1.0, yet more preferably of from >11.0: 1.0 to 60: 1.0, still more preferably of from >12.0: 1.0 to 50: 1.0. 220842W001 1 L023824PCT 22 October 7, 2025

[0152] BASF Coatings GmbH

[0153] Component B)

[0154] Component B), which represents a hardener component, comprises at least constituent b1) and optionally one or both of constituents b2) and b3), which are different from one another, but may comprise further optional constituent(s).

[0155] Preferably, in component B) 5.0 to 80.0 mol-%, more preferably 10.0 to 70.0 mol-%, even more preferably 15.0 to 60.0 mol-%, still more preferably 20.0 to 50.0 mol-%, yet more preferably 25.0 to 45.0 mol-%, of all originally present isocyanate groups, based on the total molar amount of all originally present isocyanate groups of all isocyanate groups containing constituents present in component B) including constituent b1) and optional constituent b2), have undergone reaction with at least one silane prior to its / their incorporation into component B), preferably to form structural units (I) and / or (II) as defined hereinafter.

[0156] Preferably, component B) of the coating system has a total solids content, which is >40 wt.-%, more preferably >45 wt.-%, even more preferably >50 wt.-%, still more preferably >55 wt.-%, in each based on the total weight of component B). The total solids content of component B) of the coating system is preferably in a range of from 45 to 100 wt.-%, more preferably of from 50 to <100 wt.-%, even more preferably of from 55 to <100 wt.-%, based in each case on the total weight of component B). The total solids content, in other words the non-volatile fraction, is determined in accordance with the method described hereinafter.

[0157] Constituent b1)

[0158] Constituent b1) is at least one organic constituent b1) bearing on average two or more isocyanate groups, wherein at least a part of these isocyanate groups has been reacted with at least one silane prior to incorporation of constituent b1) into component B).

[0159] Examples of constituents b1) are, e.g., disclosed in WO 2009 / 077181 A1 , WO 2010 / 139375 A1 , WO 2010 / 063332 A1 , WO 2014 / 086530 A1 , and WO 2014 / 086529 A1.

[0160] Preferably, constituent b1) bears at least one structural unit of the formula (I)

[0161] -NR-(X-SIR"X(OR')3-X) (I), and / or, preferably and, at least one structural unit of the formula (II)

[0162] -N(X-SiR"x(OR')3-x)n(X'-SiR"y(OR')3-y)m (II), wherein: 220842W001 1 L023824PCT 23 October 7, 2025

[0163] BASF Coatings GmbH

[0164] R = hydrogen, alkyl, cycloalkyl, aryl or aralkyl, it being possible for the carbon chain to be interrupted by nonadjacent oxygen, sulfur or NRagroups, where Ra= alkyl, cycloalkyl, aryl or aralkyl, each R' = independently of one another hydrogen, alkyl or cycloalkyl, it being possible for the carbon chain to be interrupted by nonadjacent oxygen, sulfur or NRagroups, each R' preferably = ethyl and / or methyl, each X,X' = independently of one another linear and / or branched alkylene or cycloalkylene radical having 1 to 20 carbon atoms, preferably each X,X' = alkylene radical having 1 to 4 carbon atoms, each R" = independently of one another alkyl, cycloalkyl, aryl or aralkyl, it being possible for the carbon chain to be interrupted by nonadjacent oxygen, sulfur or NRagroups, each R” preferably = alkyl radical, more particularly having 1 to 6 C atoms, n = parameter of 0 to 2, m = parameter of 0 to 2, m+n = 2, and x, y = parameter of 0 to 2.

[0165] The respective preferred alkoxy radicals (OR1) may be identical or different, but what is decisive for the structure of the radicals is the extent to which they influence the reactivity of the hydrolysable silane groups. Preferably R' is an alkyl radical, more particularly having 1 to 6 carbon atoms. Particularly preferred are radicals R' which increase the reactivity of the silane groups, i.e., represent good leaving groups. Accordingly, a methoxy radical is preferred over an ethoxy radical, which in turn is preferred over a propoxy radical. With particular preference, therefore, R' = ethyl and / or methyl, more particularly methyl. The reactivity of organofunctional silanes may also be influenced considerably, furthermore, by the lengths of the spacers X, X' between silane functionality and organic functional group which serves for reaction with the constituent to be modified. Examples thereof that may be mentioned include the "alpha” silanes, which are obtainable from the company Wacker, and in which there is a methylene group, instead of the propylene group present in the case of "gamma” silanes, between Si atom and functional group.

[0166] In constituent b1) preferably, between 10 and 80 mol-%, preferably between 15 and 70 mol-%, more preferably between 20 and 50 mol-% and still more preferably between 25 and 40 mol-% of the isocyanate groups originally present have undergone reaction with the at least one silane, preferably to form structural units (I) and / or (II), more preferably to form structural units (I) and (II).

[0167] Moreover, preference is given to constituent b1), in which the total amount of structural units (I) is between 3 and 90 mol-%, more preferably between 5 and 70 mol-%, based in each case on the entirety of the structural units (I) plus (II), and the total amount of structural units (II) is between 97 and 10 mol-%, more preferably between 95 and 30 mol-%, based in each case on the entirety of the structural units (I) plus (II).

[0168] The at least one organic constituent b1) bearing on average two or more NCO-groups, which serves - before reaction with at the least one silane - as the parent structure for the constituent b1) represent at this stage before reaction with the at least one silane a di- and / or polyisocyanate. Preferably, said at least one di- and / or 220842W001 1 L023824PCT 24 October 7, 2025

[0169] BASF Coatings GmbH polyisocyanate is an aromatic, aliphatic, cycloaliphatic, and / or heterocyclic di- and / or polyisocyanate, in particular an aliphatic alicyclic and / or cyclic di- and / or polyisocyanate.

[0170] Preferably, the at least one organic constituent b1) present in component B) has an aliphatic or cycloaliphatic structure and / or a parent structure that is derived from an aliphatic or cycloaliphatic polyisocyanate by trimerization, dimerization, urethane formation, biuret formation, uretdione formation and / or allophanate formation. Trimers, i.e., isocyanurates, of IPDI (isophorone diisocyanate) and / or HDI (hexamethylene diisocyanate) are particularly preferred.

[0171] Preferably, the at least one organic constituent b1) has a cycloaliphatic parent structure and / or a parent structure, it is derived from a cycloaliphatic polyisocyanate by trimerization, dimerization, urethane formation, biuret formation, uretdione formation and / or allophanate formation, wherein constituent b1) has at least one structural unit of the formula (I) and / or (II). Alternatively, or additionally, the at least one organic constituent b1) preferably has an acyclic aliphatic parent structure and / or a parent structure that is derived from an acyclic aliphatic polyisocyanate by trimerization, dimerization, urethane formation, biuret formation, uretdione formation and / or allophanate formation, wherein constituent b1) has at least one structural unit of the formula (I) and / or (II).

[0172] Most preferably, the at least one organic constituent b1) has an acyclic aliphatic parent structure and / or a parent structure that is derived from an acyclic aliphatic polyisocyanate by trimerization, dimerization, urethane formation, biuret formation, uretdione formation and / or allophanate formation, wherein constituent b1) has at least one structural unit of the formula (I) and / or (II). Trimers, i.e., isocyanurates, are particularly preferred.

[0173] The acyclic aliphatic polyisocyanates serving as parent structures are preferably substituted or unsubstituted aliphatic polyisocyanates that are known per se. Examples are 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.

[0174] Additionally preferred polyisocyanate parent structures are the polyisocyanates derived from such an acyclic aliphatic polyisocyanate by trimerization, dimerization, urethane formation, biuret formation, uretdione formation and / or allophanate formation, more particularly the biuret dimer and / or the allophanate dimer and / or the isocyanurate trimer. The polyisocyanate parent structures may also be polyisocyanate prepolymers having urethane structural units which are obtained by reaction of polyols with a stoichiometric excess of aforementioned acyclic aliphatic polyisocyanates. Polyisocyanate prepolymers of this kind are described for example in US-A- 4,598, 131. Particularly preferred polyisocyanate parent structures are hexamethylene diisocyanate and / or its biuret dimer and / or allophanate dimer and / or isocyanurate trimer and / or its uretdione, and also mixtures of the stated polyisocyanate parent structures. Especially preferred polyisocyanate parent structures are hexamethylene diisocyanate and / or its isocyanurate trimer, optionally together with its uretdione. 220842W001 1 L023824PCT 25 October 7, 2025

[0175] BASF Coatings GmbH

[0176] The cycloaliphatic polyisocyanates used as parent structures are preferably substituted or unsubstituted cycloaliphatic polyisocyanates which are known per se. Examples of preferred polyisocyanates are isophorone diisocyanate, cyclobutane 1 ,3-diisocyanate, cyclohexane 1 ,3-diisocyanate, cyclohexane 1 ,4-diisocyanate, methylcyclohexyl diisocyanates, hexahydrotoluene 2,4-diisocyanate, hexahydrotoluene 2,6-diisocyanate, hexahydrophenylene 1 ,3-diisocyanate, hexahydrophenylene 1 ,4-diisocyanate, perhydrodiphenylmethane 2,4'- diisocyanate, 4,4’-methylendicyclohexyl diisocyanate (e.g. Desmodur ® W from Bayer AG) and mixtures of the aforementioned polyisocyanates. Additionally preferred polyisocyanate parent structures are the polyisocyanates derived from such a cycloaliphatic polyisocyanate by trimerization, dimerization, urethane formation, biuret formation, uretdione formation and / or allophanate formation, more particularly the biuret dimer and / or the allophanate dimer and / or the isocyanurate trimer. The polyisocyanate parent structures may be ppolyisocyanate prepolymers having urethane structural units which are obtained by reaction of polyols with a stoichiometric excess of aforementioned cycloaliphatic polyisocyanates. Such polyisocyanate prepolymers are described for example in US-A-4,598, 131 . Particularly preferred cycloaliphatic polyisocyanates are isophorone diisocyanate and 4,4'- methylenedicyclohexyl diisocyanate and / or the biuret dimers thereof and / or the allophanate dimers thereof and / or the isocyanurate trimers thereof.

[0177] The at least one silane used for reaction with at least one organic constituent b1) bearing on average two or more NCO-groups prior to incorporation of b1) into the (B) component is preferably at least one compound of the formula (la)

[0178] H-NR-(X-SIR"X(OR')3-X) (la), and / or at least one compound of the formula (Ila) HN(X-SIR"x(OR')3-x)n(X'-SIR"y(OR')3-y)m(Ila), where the substituents have the definitions stated above including the preferred definitions.

[0179] Preferred compounds (la) are aminoalkyltrialkoxysilanes, such as, preferably, 2-aminoethyltrimethoxysilane, 2- aminoethyltriethoxysilane, 3-aminopropyltrimethoxy-silane, 3-aminopropyltriethoxysilane, 4-amino- butyltrimethoxysilane, 4-aminobutyltriethoxysilane. Particularly preferred compounds (la) are N-(2- (trimethoxysilyl)ethyl)alkylamines, N-(3-(trimethoxysilyl)propyl)alkylamines, N-(4-(trimethoxysilyl)butyl)alkylamines, N-(2-(triethoxysilyl)ethyl)alkylamines, N-(3-(triethoxysilyl)propyl)alkylamines and / or N-(4- (triethoxysilyl)butyl)alkylamines. Especially preferred is N-(3-(trimethoxysilyl)propyl)butylamine. Aminosilanes of these kinds are available for example under the brand name DYNASYLAN® from DEGUSSA or Silquest® from OSI.

[0180] Preferred compounds (Ila) are bis(2-ethyltrimethoxysilyl)amine, bis(3-propyltrimethoxysilyl)amine, bis(4- butyltrimethoxysilyl)amine, bis(2-ethyltriethoxysilyl)amine, bis(3-propyltriethoxysilyl)amine and / or bis(4- 220842W001 1 L023824PCT 26 October 7, 2025

[0181] BASF Coatings GmbH buty Itriethoxysi ly l)ami ne. Especially preferred is bis(3-propy Itrimethoxysily l)ami ne. Aminosilanes of these kinds are available for example under the brand name DYNASYLAN® from DEGUSSA or Silquest® from Momentive.

[0182] Optional constituent b2)

[0183] Optional organic constituent b2) is different from organic constituent b1) and bears on average two or more isocyanate groups, wherein none of the isocyanate groups of constituent b2) has been reacted with at least one silane prior to incorporation of constituent b2) into component B). Thus, the at least one organic constituent b2) bearing on average two or more NCO-groups does not contain any silane modified NCO-groups.

[0184] Preferably, the at least one organic constituent b2) may optionally be present in component B), more preferably in an amount that exceeds the amount of constituent b1), preferably both by weight and in the sense of a molar amount.

[0185] Preferably, the at least one organic constituent b2) optionally present in component B) has an aliphatic or cycloaliphatic structure and / or a parent structure that is derived from an aliphatic or cycloaliphatic polyisocyanate by trimerization, dimerization, urethane formation, biuret formation, uretdione formation and / or allophanate formation. Trimers, i.e., isocyanurates, of IPDI (isophorone diisocyanate) and / or HDI (hexamethylene diisocyanate) are particularly preferred.

[0186] Suitable aliphatic polyisocyanates are preferably substituted or unsubstituted aliphatic polyisocyanates such as 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. Suitable polyisocyanate parent structures may be polyisocyanate prepolymers having urethane structural units which are obtained by reaction of polyols with a stoichiometric excess of aforementioned aliphatic polyisocyanates. Particularly preferred polyisocyanate parent structures are hexamethylene diisocyanate and / or its biuret dimer and / or allophanate dimer and / or isocyanurate trimer and / or its uretdione, and also mixtures of the stated polyisocyanate parent structures. Especially preferred polyisocyanate parent structures are hexamethylene diisocyanate and / or its isocyanurate trimer, optionally together with its uretdione.

[0187] Suitable cycloaliphatic polyisocyanates are preferably substituted or unsubstituted cycloaliphatic polyisocyanates such as isophorone diisocyanate, cyclobutane 1 ,3-diisocyanate, cyclohexane 1 ,3-diisocyanate, cyclohexane 1 ,4- diisocyanate, methylcyclohexyl diisocyanates, hexahydrotoluene 2,4-diisocyanate, hexahydrotoluene 2,6- diisocyanate, hexahydrophenylene 1 ,3-diisocyanate, hexahydrophenylene 1 ,4-diisocyanate, perhydrodiphenylmethane 2,4'-diisocyanate and 4,4'-methylendicyclohexyl diisocyanate and mixtures of the aforementioned polyisocyanates. Suitable polyisocyanate parent structures may be polyisocyanates derived from a cycloaliphatic polyisocyanate by trimerization, dimerization, urethane formation, biuret formation, uretdione formation and / or allophanate formation, more particularly the biuret dimer and / or the allophanate dimer and / or the isocyanurate trimer. The polyisocyanate parent structures may be polyisocyanate prepolymers having urethane 220842W001 1 L023824PCT 27 October 7, 2025

[0188] BASF Coatings GmbH structural units which are obtained by reaction of polyols with a stoichiometric excess of aforementioned cycloaliphatic polyisocyanates. Particularly preferred cycloaliphatic polyisocyanates are isophorone diisocyanate and 4, 4'-methy lened icyclohexy I diisocyanate and / or the biuret dimers thereof and / or the allophanate dimers thereof and / or the isocyanurate trimers thereof.

[0189] Optional constituent b3)

[0190] Optional constituent b3) is at least one organic solvent. Examples of such organic solvents include the ones already mentioned hereinbefore in connection with constituent a4). Component B) may comprise more than one organic solvent b3). The at least one organic solvent b3) may the identical to or different from the at least one organic solvent a4) and / or d). If more than one organic solvent is used as a4) and / or b3) it may be that a4) and b3) are both partially identical and partially different.

[0191] Preferably, the amount of constituent b3) in component B), if present, is in the range of from 5 to 50 wt.-%, more preferably of from 10 to 40 wt.-%, even more preferably of from 15 to 35 wt.-%, based in each case on the total weight of component B).

[0192] Optional component (C)

[0193] Optional component C) is a reducer component and comprises at least one organic solvent d) and preferably consists of at least one organic solvent d). Examples of such organic solvents include the ones already mentioned hereinbefore in connection with constituents a4) and b3). Component C) may comprise more than one organic solvent d). The at least one organic solvent d) may the identical to or different from the at least one organic solvent a4) and / or b3). If more than one organic solvent is used as a4) and / or b3) and / or d) it may be that a4) and / or b3) and / or d) are both partially identical and partially different.

[0194] Coatinci composition

[0195] A further subject-matter of the present invention is a clearcoat composition obtainable by mixing components A) and B) and optionally C) of the coating system with each other.

[0196] All preferred embodiments described above herein in connection with the inventive coating system and the preferred embodiments thereof, are also preferred embodiments of the inventive coating composition.

[0197] The preparation of the coating composition can be carried out using customary and known preparation and mixing methods and mixing units, or using conventional dissolvers and / or stirrers.

[0198] Preferably, the clearcoat composition is a solventborne, i.e., an organic solvent(s) based, coating composition, preferably due to the presence of constituents a4) and / or b3) and optionally d). The term "solventborne” in 220842W001 1 L023824PCT 28 October 7, 2025

[0199] BASF Coatings GmbH connection with the coating composition is understood preferably for the purposes of the present invention to mean that the aforementioned organic solvent(s), as solvent and / or as diluent, is / are present as the main constituent(s) of all solvents and / or diluents present therein, preferably in an amount of at least 35 wt.-%, based on the total weight of the coating composition. Thus, preferably, the coating composition is not a waterborne, i.e., an aqueous, coating composition.

[0200] The coating composition preferably includes an organic solvent(s) fraction of at most 65 wt.-%, more preferably of at most 60 wt.-%, even more preferably of at most 55 wt.-%, still more preferably of at most 50 wt.-%, yet more preferably of at most 48 wt.-%, in particular of at most 45 wt.-% or of at most 40 wt.-% or of at most 35 wt.-% or of at most 30 wt.-%, based in each case on the total weight of the coating composition. All conventional organic solvents known to those skilled in the art can be used as organic solvents, i.e., as constituents a4) and b3) and optionally d). The term "organic solvent" is known to those skilled in the art, in particular from Council Directive 1999 / 13 / EC of 11 March 1999. Examples of the organic solvents which can be used have been mentioned hereinbefore in connection with constituents a4) and b3) and d).

[0201] Preferably, the coating composition has a total solids content, which is >35 wt.-%, more preferably >40 wt.-%, even more preferably >45 wt.-%, still more preferably >50 wt.-%, based in each case on the total weight of the coating composition. The total solids content of the coating composition is preferably in a range of from >35 to 75 wt.-%, more preferably of from >40 to 70 wt.-%, even more preferably of from >45 to 65 wt.-%, still more preferably of from >48 to 60 wt.-%, based in each case on the total weight of the coating composition. The total solids content, in other words the non-volatile fraction, is determined in accordance with the method described hereinafter.

[0202] The clearcoat compositions of the invention are employed in particular in the technologically and esthetically particularly demanding field of automotive OEM finishing and also of automotive refinish.

[0203] The term "clear coat”, "clearcoat” or "clear coating” is known to a person skilled in the art and preferably represents a substantially transparent or transparent outermost layer preferably of a multilayer coating structure applied to a substrate.

[0204] Preferably, the clearcoat composition is obtainable by mixing components A) and B) in a weight ratio (component A) / component B)) in the range of from 6: 1 to 1 :3. More preferably, mixing is performed in a weight ratio in the range of from 5: 1 to 1 :2, even more preferably in a weight ratio in the range of from 4:1 to 1 : 1.5, in particular in a weight ratio in the range of from 3.5:1 to 1 :1.2, still more preferred in a weight ratio in the range of from 3.1 :1 to 1 : 1 , most preferably of from 3.1 :1 to 2.5:1.

[0205] Preferably, the clearcoat composition does not comprise more than 5 wt.-% of pigments and / or fillers, based on its total weight, since otherwise the transparency or desired clarity of the clearcoat coating layer produced from the 220842W001 1 L023824PCT 29 October 7, 2025

[0206] BASF Coatings GmbH composition could be affected. More preferably, the clearcoat composition is free of any pigments and / or fillers, in particular of any effect pigments.

[0207] Method of coating

[0208] A further subject-matter of the present invention is a method of coating a substrate, comprising at least one step of applying to an optionally pre-coated substrate the inventive clearcoat composition, preferably via spray application, to form at least one coating film onto the optionally pre-coated substrate, and optionally comprising at least one further step of curing the at least one coating film to obtain at least one cured coating layer onto the substrate.

[0209] All preferred embodiments described hereinabove in connection with the inventive coating system and clearcoat composition are also preferred embodiments with regard to the aforementioned inventive method.

[0210] The pre-coated substrate can be a substrate that already bears a coating system on at least one of its surfaces, e.g., an electrodeposition coat, onto which at least one of a primer, filler and basecoat material has been applied. The pre-coated substrate can also be a substrate that bears on at least one of its surfaces, e.g., an electrodeposition coat, and no further coating layers applied on top of said layer.

[0211] Preferably, the inventive method is a method of preparing a multilayer coating system onto an optionally pre-coated substrate comprising at least steps 1), 3), and 4), and optionally 2), namely

[0212] 1) applying a first coating composition to an optionally pre-coated substrate and forming a first coating film on the optionally pre-coated substrate,

[0213] 2) optionally applying a second coating composition, which is different from the first coating composition, to the first coating film present on the substrate obtained after step 1) prior to curing the first coating film and forming a second coating film adjacent to the first coating film,

[0214] 3) applying a third coating composition, which is different from the first and second coating composition, to the first coating film present on the substrate obtained after step 1) prior to curing the first coating film and forming a third coating film adjacent to the first coating film in case optional step 2) is not performed or applying a third coating composition to the second coating film present on the substrate obtained after step 2) prior to curing the second coating film and forming a third coating film adjacent to the second coating film in case optional step 2) is performed, wherein the third coating composition is an inventive clearcoat composition as defined hereinbefore and hereinafter, and 220842W001 1 L023824PCT 30 October 7, 2025

[0215] BASF Coatings GmbH

[0216] 4) jointly curing the first and third and optionally second coating films, the cured third coating film being the outermost layer of the formed multilayer coating system, to obtain cured first, optionally second, and third coating layers.

[0217] Examples of coating compositions that are applied as first coating composition are primer and basecoat compositions. Examples of coating compositions that are applied as second coating composition are basecoat compositions. The term "primer” is known to a person skilled in the art. A primer typically is applied after the substrate has been provided with a cured electrodeposition coating layer in case of metallic substrates. In this case, the cured electrodeposition coating film is present underneath and preferably adjacent to the primer coating film. This is an example of a pre-coated substrate. In case of non-metallic substrates such as plastic substrates including fiber reinforced plastic substrates the primer coating film typically represents the first coating film applied onto their surfaces. The term "basecoat” is known to a person skilled in the art as well and, for example, defined in Rdmpp Lexikon, paints and printing inks, Georg Thieme Verlag, 1998, 10th edition, page 57. A basecoat is therefore in particular used in automotive painting and general industrial paint coloring in order to give a coloring and / or an optical effect by using the basecoat as an intermediate coating composition. This is generally applied to a metal or plastic substrate, in each case being optionally pre-coated. In order to protect a basecoat film in particular against environmental influences, at least one additional clearcoat film is applied to it. The term "clear coat”, "clearcoat” or "clear coating” is also known to a person skilled in the art and represents a transparent outermost layer of a multilayer coating structure applied to a substrate.

[0218] Any type of basecoat and primer composition can be used, e.g., a 1 K- or 2K-basecoat or primer composition, preferably a 1 K-composition, which may be solventborne or aqueous and may contain coloring and / or effect pigments. Preferably, the basecoat or primer composition comprises at least one film-forming binder, preferably at least one polymer, more preferably at least one polymer, which has functional groups that are reactive towards NCO-groups. Optionally, the basecoat or primer composition may include at least one crosslinking agent, preferably selected from melamine formaldehyde resins and / or preferably blocked polyisocyanates, in particular in case the at least film-forming binder is an externally crosslinking polymer.

[0219] Preferably, at least step 3), more preferably also step 1) and optional step 2) is performed via a spray application.

[0220] The first, optionally second, and third coating film formed on the optionally pre-coated substrate by performing step 1), optional step 2), and step 3) are at this stage each an uncured coating film. Thus, both the first and the optionally second and the third coating compositions are applied wet-on-wet.

[0221] The method of the invention is particularly suitable for the coating of automotive vehicle bodies or parts thereof including respective metallic substrates, but also plastic substrates such as polymeric substrates. Consequently, the preferred substrates are automotive vehicle bodies or parts thereof. 220842W001 1 L023824PCT 31 October 7, 2025

[0222] BASF Coatings GmbH

[0223] Suitability as metallic substrates used in accordance with the invention are all substrates used customarily and known to the skilled person. The substrates used in accordance with the invention are preferably metallic substrates, more preferably selected from the group consisting of steel, preferably steel selected from the group consisting of bare steel, cold rolled steel (CRS), hot rolled steel, galvanized steel such as hot dip galvanized steel (HDG), alloy galvanized steel (such as, for example, Galvalume, Galvannealed or Galfan) and aluminized steel, aluminum, and magnesium, and also Zn / Mg alloys and Zn / Ni alloys. Particularly suitable substrates are parts of vehicle bodies or complete bodies of automobiles for production.

[0224] The substrate used in accordance with the invention is preferably a metallic substrate pretreated with at least one metal phosphate such as zinc phosphate and / or pretreated with at least one an oxalate. A pretreatment of this kind by means of phosphating or oxalating, which takes place normally after the substrate has been cleaned and before the substrate is electrodeposition-coated, is in particular a pretreatment step that is customary in the automobile industry. The metallic substrate may further comprise a cured electrodeposition coating layer as pre-coat.

[0225] Preferably, thermoplastic polymers are used as plastic substrates. Suitable polymers are poly(meth)acrylates including polymethyl(meth)acrylates, polybutyl (meth)acrylates, polyethylene terephthalates, polybutylene terephthalates, polyvinylidene fluorides, polyvinyl chlorides, polyesters, including polycarbonates and polyvinyl acetate, polyamides, polyolefins such as polyethylene, polypropylene, polystyrene, and also polybutadiene, polyacrylonitrile, polyacetal, polyacrylonitrile-ethylene-propylene-diene-styrene copolymers (A-EPDM), ASA (acrylonitrile-styrene-acrylic ester copolymers) and ABS (acrylonitrile-butadiene-styrene copolymers), polyetherimides, phenolic resins, urea resins, melamine resins, alkyd resins, epoxy resins, polyurethanes, including TPU, polyetherketones, polyphenylene sulfides, polyethers, polyvinyl alcohols, and mixtures thereof. Polycarbonates and poly(meth)acrylates are especially preferred. Further, fiber reinforced plastic substrates are used. Glass and / or carbon fibers can be in particular used for reinforcement, most preferably carbon fibers.

[0226] As outlined above the substrate used may be a pre-coated substrate, i.e., a substrate bearing at least one cured coating film. The substrate used in step 1) can be pre-coated with a cured electrodeposition coating layer. The substrate can, e.g., be provided also with at least one cured primer coating film as at least one additional pre-coat. The term "primer” is known to a person skilled in the art. A primer typically is applied after the substrate has been provided with a cured electrodeposition coating layer. In case a cured primer coating film is also present, the cured electrodeposition coating film is present underneath and preferably adjacent to the cured primer coating film.

[0227] Preferably, the inventive method further comprises a step 1a), which is carried out after step 1) and before optional step 2). In said step 1a) the first coating film obtained after step 1) is flashed-off before applying the second coating material composition in optional step 2) preferably for a period of 1 to 20 minutes, more preferably for a period of 2 to 15 minutes, in particular for a period of 5 to 10 minutes. Preferably, step 1 a) is performed at a temperature not exceeding 40°C, more preferably at a temperature in the range of from 18 to 30°C. 220842W001 1 L023824PCT 32 October 7, 2025

[0228] BASF Coatings GmbH

[0229] Preferably, the inventive method further comprises a step 2a), which is carried out after step 2) and before step 3). In said step 2a) the second coating film obtained after step 2) is flashed-off before applying the third coating material composition in step 3) preferably for a period of 1 to 20 minutes, more preferably for a period of 2 to 15 minutes, in particular for a period of 5 to 10 minutes. Preferably, step 2a) is performed at a temperature not exceeding 40°C, more preferably at a temperature in the range of from 18 to 30°C.

[0230] Preferably, the inventive method further comprises a step 3a), which is carried out after step 3) and before step 4). In said step 3a) the third coating film obtained after step (3) is flashed-off before performing curing step 4) preferably for a period of 1 to 20 minutes, more preferably for a period of 2 to 15 minutes, in particular for a period of 5 to 10 minutes. Preferably, step 3a) is performed at a temperature not exceeding 40°C, more preferably at a temperature in the range of from 18 to 30°C.

[0231] The term "flashing off” in the sense of the present invention preferably means a drying, wherein at least some and / or some amounts of the organic solvents are evaporated from the coating film, before the next coating composition is applied and / or a curing is carried out. No curing is performed by the flashing-off.

[0232] In step 4) of the inventive method the first and third coating films and optionally also the second coating film are jointly cured, i.e., are cured together simultaneously. The cured third coating film represents the outermost layer of the formed multilayer coating system obtained after step 4).

[0233] Each resulting cured coating film represents a coating layer. Thus, after performing step 4) a first and third and optionally also second coating layer are formed on the optionally pre-coated substrate, with the third layer being the outermost layer of the formed multilayer coating system.

[0234] Preferably, step 4) is performed at a temperature in a range of from 80 to 180 °C, more preferably in a range of from 100 to 170 °C, even more preferably in a range of from 120 to 160 °C, still more preferably in a range of from 130 to 150 °C, in each case for a period of 5 to 45 minutes, preferably for a period of 10 to 40 minutes, in particular for a period of 12.5 to 35 minutes, most preferably for a period of 15 to 30 minutes.

[0235] Preferably, the cured first coating film (layer L1), preferably obtained after having performed step 4) of the inventive method of preparing a multilayer coating system, has a dry film thickness in a range of from 10 to 35 pm. Preferably, the cured second film (layer L2), if present, preferably obtained after having performed step 4) of the inventive method of preparing a multilayer coating system, has a dry film thickness in a range of from 10 to 35 pm. Preferably, the cured clearcoat film (layer L3), preferably obtained after having performed step 4) of the inventive method of preparing a multilayer coating system, has a dry film thickness in a range of from 30 to 80 pm, more preferably of from 30 to 70 pm. 220842W001 1 L023824PCT 33 October 7, 2025

[0236] BASF Coatings GmbH

[0237] Coated substrate

[0238] A further subject-matter of the present invention is a coated substrate, which is obtainable by the inventive method.

[0239] All preferred embodiments described hereinabove in connection with the inventive coating system and clearcoat composition and method are also preferred embodiments with regard to the aforementioned inventive coated substrate.

[0240] Multilayer coating system

[0241] A further subject-matter of the present invention is a multilayer coating system being present on an optionally precoated substrate and comprising at least two coatings layers L1 and L3 and optionally at least one coating layer L2 being different from one another, namely a first coating layer L1 applied over at least a portion of an optionally pre-coated substrate, said layer L1 being preferably obtainable from the first coating composition applied in step 1) of the inventive method, optionally a second coating layer L2 applied over the first coating layer L1 , said layer L2 being preferably obtainable from the second coating composition applied in optional step 2) of the inventive method, and a third coating layer L3 applied over the first coating layer L1 or, if present, over the second coating layer L2, said layer L3 being obtainable from the inventive clearcoat composition.

[0242] All preferred embodiments described hereinabove in connection with the inventive coating system, clearcoat composition, method and coated substrate are also preferred embodiments with regard to the aforementioned inventive multilayer coating system.

[0243] Preferably, the at least two coatings layers L1 and L3 as well as optionally present layer L2 are being positioned adjacently to each other. Preferably, the third coating layer L3 is the outermost coating layer of the multilayer coating system.

[0244] Preferably, the multilayer coating system is obtainable by the inventive method of preparing a multilayer coating system, which has been described in detail hereinbefore. 220842W001 1 L023824PCT 34 October 7, 2025

[0245] BASF Coatings GmbH

[0246] METHODS

[0247] 1. Non-volatile fraction

[0248] The non-volatile fraction (solid fraction, solid content) was determined according to DIN EN ISO 3251 :2018-07 at 140°C for 60 min.

[0249] 2. Hydroxyl value

[0250] The hydroxyl value indicates the quantity of KOH in mg that is equivalent to the amount of acetic acid bound in the acetylation of 1 g of sample. The hydroxyl value is based on the solids content of the sample. For the determination, if not indicated otherwise, the sample was boiled with acetic anhydride-pyridine and the resultant acid was titrated with potassium hydroxide solution (DIN EN ISO 4629-2:2016-12).

[0251] 3. Acid number

[0252] The acid number was determined according to DIN EN ISO 2114 (date: June 2002), using "method A”. The acid number corresponds to the mass of potassium hydroxide in mg required to neutralize 1 g of sample under the conditions specified in DIN EN ISO 2114. The acid number reported corresponds here to the total acid number as specified in the DIN standard and is based on the solids content.

[0253] 4. Weight-average molecular meight Mwand number-average molecular weight Mn

[0254] To determine polymer molecular weights by GPC, fully dissolved polymer samples were fractionated on a porous column stationary phase. A 0.1 mol / l acetic acid solution in tetrahydofuran (THF) was used as the eluent solvent. The stationary phase was a combination of Waters Styragel® HR 5, HR 4, HR 3, and HR 2 columns. Five milligrams of sample are added to 1 .5 mL of eluent solvent and filtered through a 0.5 pm filter. After filtering, 100 pl of the polymer sample solution is injected into the column at a flow rate of 1 .0 mL / min. Separation takes place according to the size of the polymer coils which form in the eluent solvent. Small molecules diffuse into the pores of the column material more frequently and are therefore retarded more than large molecules. Thus, large molecules are eluted earlier than small molecules. The molecular weight distribution, the number-average Mnand weight-average Mwand the polydispersity Mw / Mnof the polymer samples are calculated with the aid of chromatography software utilizing a calibration curve generated with the EasyValid validation kit which includes a series of unbranched-polystyrene standards of varied molecular weights available from Polymer Standards Service.

[0255] 5. Glass transition temperature Tg

[0256] The glass transition temperature was measured by means of DSC measurements in accordance with DIN EN ISO 11357-2 (2019-03).

[0257] 6. Dry layer thickness

[0258] Dry layer thicknesses (DLT) were determined in accordance with DIN EN ISO 2808:2019-12, method 12A using the MiniTest® 3100-4100 measuring device from ElektroPhysik. 220842W001 1 L023824PCT 35 October 7, 2025

[0259] BASF Coatings GmbH

[0260] 7. Gloss

[0261] Gloss (G) was determined in accordance with DIN EN ISO 2813:2015-02 at 60 ° using a Byk wave scan meter 2. 8. Average particle size

[0262] The average particle size is a median particle size (volume based) and was determined, in particular for both constituents a2) and a3), by DLS (dynamic light scattering) in accordance with DIN ISO 22412:2018-09 using a Malvern Mastersizer device such as a Malvern Mastersizer 3000.

[0263] 220842W001 1 L023824PCT 36 October 7, 2025

[0264] BASF Coatings GmbH

[0265] EXAMPLES

[0266] The following examples further illustrate the invention but are not to be construed as limiting its scope.

[0267] 1. Preparation of clearcoat compositions

[0268] 1.1 Inventively used “A”-component 11 as well as comparatively used “A” component C1 for preparing clearcoat compositions

[0269] Inventively used "A”-component 11 as well as comparatively used "A” component C1 have been prepared by mixing the constituents listed in Table 1 in this order. “wt.-%” means percentage by weight.

[0270] Table 1 : "A'-components 11 and 01

[0271] Z 100.00 100.00

[0272] PAC1 is an organic solvent(s) comprising dispersion containing a (meth)acrylic copolymer having an OH number of about 175 mg KOH / g, an acid number of about 10 mg KOH / g, a measured glass transition temperature of -13 °C and a weight average molecular weight of about 18 000 g / mol. The dispersion had a solid content of 65 wt.-%. PAC2 is an organic solvent(s) containing dispersion containing a (meth)acrylic copolymer having an OH number of about 185 mg KOH / g, an acid number of about 12 mg KOH / g, a measured glass transition temperature of about +7 to +10 °C and a weight average molecular weight of about 8 000 g / mol. The dispersion has a solid content of 65 wt.-%. 220842W001 1 L023824PCT 37 October 7, 2025

[0273] BASF Coatings GmbH

[0274] Thixotropic paste TP1 contains 10.0 wt.-% of Aerosil® R 106, which is a commercially available hydrophobic fumed silica, 46.0 wt.-% of organic solvents (solventnaphtha and butanol) and 44.0 wt.-% of PACT TP1 was prepared by mixing and stirring the aforementioned constituents for 30 minutes by means of a dissolver and by subsequent milling in a mill with suitable grinding media at an energy input of 0.14 kwh / kg, wherein the temperature was monitored to not exceed 65 °C.

[0275] As blocked polyisocyanate a commercially available product having a solid content of about 75 wt.-% has been used, which is an aliphatic polyisocyanate based on HDI that has been blocked with DMP (dimethyl pyrazole).

[0276] A commercially available defoamer and a commercially available polymeric wetting and dispersing additive have been used. A commercially available UV absorber (a substituted benzotriazole) has been used. A commercially available light stabilizer (a hindered amine light stabilizer; HALS) has been used. A commercially available surface additive being a polyester modified polydimethylsiloxane has been used. A commercially available phosphate containing catalyst has been used as catalyst.

[0277] A commercially available amorphous silica matting agent has been used as matting agent, having an average particle size (median) of about 6 pm.

[0278] 1.2 Preparation of a crosslinker component (“B”-component B1) for preparing clearcoat compositions

[0279] Inventively used "B”-component B1 has been prepared as described hereinafter.

[0280] In a reaction vessel, 33.93 pbw of hexamethyl 1 ,6-diisocyanate (HDI) trimer (Desmodur® N3600) and 23.75 pbw of butyl acetate were introduced. With reflux cooling, nitrogen blanketing and stirring, a mixture of 0.91 pbw of N- [3-(trimethoxysilyl)propyl]butylamine (Dynasylan® 1189) and 19.95 pbw of bis[3-trimethoxysilylpropyl]amine (Dynasylan® 1124) were added dropwise at a rate such that a temperature of 80 ° C was not exceeded. The reaction mixture was then stirred, after the additions were completed, for another 60 minutes at 60 °C. The resulting polyisocyanate had an NCO content of 6.1 % by weight and a solid content of 100 wt.-%. The contents of the reactor were then drained into a solvent vessel. Then 8.54 pbw isophorone diiocyanate (IPDI) trimer (Desmodur® Z4470, 70 wt.-% in solventnaphtha), 3.18 pbw 2-methoxy-1 -methylethyl acetate, 4.00 pbw butyl acetate, 4.09 pbw of a dibasic ester and 1 .65 pbw tris-2-ethylhexyl amine were added into the reactor and then also drained into the dissolving vessel. The resulting polyisocyanate mixture had an NCO content of 5.9 % by weight (based on the solid content) and a solid content of 60.8 % by weight. 31 mol-% of all NCO-groups in total (based on all NCO-groups originally present) were present in a silanized form within the polyisocyanate prepared in this manner. This polyisocyanate as such was used as "B”-component B1. 220842W001 1 L023824PCT 38 October 7, 2025

[0281] BASF Coatings GmbH

[0282] 1.3 Preparation of clearcoat compositions

[0283] Each of the "A” components C1 and 11 was mixed with crosslinker “B” component B1 in a 100:33 weight ratio. In this manner compositions C1 B1 and 11 B1 were obtained.

[0284] 2. Preparation of multilayer coating systems

[0285] Multilayer coating systems obtained by making use of the clearcoat compositions

[0286] A number of steel panels (20 cm x 50 cm) were dipped into a bath containing a commercially available electrodeposition coating composition (Cathoguard® 800). Then, the coated substrate was baked for 15 minutes at 175 °C (dry film thickness: 20 pm). Afterwards, a commercially available aqueous black basecoat composition was spray-applied subsequently onto the cured electrodeposition coat. The basecoat was flashed off at 70 °C for 5 minutes. Afterwards, clearcoat composition C1 B1 was applied both horizontally and vertically onto the coated steel panels in different dry layer thicknesses ranging from about 49 to 64 pm. Finally, curing of all coats at 140°C for 20 minutes was performed.

[0287] The same procedure was performed for a number of further steel panels with the exception that not clearcoat composition C1 B1 but instead clearcoat composition 11 B1 was used.

[0288] 3. Properties of the substrates coated with the multilayer coating systems

[0289] The substrates coated with the multilayer coating system including the horizontally and vertically applied clearcoat layer were investigated in that a) the dry layer thicknesses (DLT) and b) the gloss (G) (at a 60 ° angle) thereof was measured according to the methods disclosed in the ‘method section', each of a) and b) at three different positions on the coated panels, namely on I) their left side, II) centrally and ill) on their right side. For each of the two different kinds of coated substrates (one being coated by making of C1 B1 as clearcoat and one being coated by making use of 11 B1 as clearcoat), differences in gloss values and differences in dry layer thickness at the three aforementioned positions I) to ill) were calculated based on the respective measured values both for the horizontally (h) and vertically (v) applied clearcoats and indicated as dG- and dDLT-values. The differences in each case are the differences between the values measured for the horizontally applied clearcoats minus the values measured for the vertically applied clearcoats The results are summarized in Table 2. The lesser the dG-values are, the better and more stable is the observed overall gloss. As it is evident from Table 2, the presence of constituent a2) in combination with matting agent constituent a3) as in 11 B1 leads to a better and more stable gloss compared to C1 B1 . 220842W001 1 L023824PCT 39 October 7, 2025

[0290] BASF Coatings GmbH

[0291] Table 2

Claims

220842W001 1 L023824PCT 40 October 7, 2025BASF Coatings GmbHCLAIMS1. A clearcoat system comprising at least two components A) and B) and optionally at least one further component C) being different from one another and being separate from each other, wherein component A) comprises at least constituents a1), a2), and a3) and optionally constituent a4), which are different from one another, namely at least one OH-functional polymer as constituent a1), at least two kinds of silica constituents, namely at least one kind of fumed silica as constituent a2), and at least one kind of amorphous silica matting agent as constituent a3), which is different from constituent a2), and optionally at least one organic solvent a4), wherein the weight amount of constituent a3) exceeds the weight amount of constituent a2), and wherein the amount of constituent a3) in component A) is at least 2.5 wt.-%, based on the total weight of component A), wherein component B) comprises at least constituent b1) and optionally one or more of constituents b2) and b3), which are different from one another, namely at least one organic constituent b1) bearing on average two or more isocyanate groups, wherein at least a part of these isocyanate groups has been reacted with at least one silane prior to incorporation of constituent b1) into component B), optionally at least one organic constituent b2) being different from organic constituent b1) and bearing on average two or more isocyanate groups, wherein none of the isocyanate groups of constituent b2) has been reacted with at least one silane prior to incorporation of constituent b2) into component B), optionally at least one organic solvent b3), and wherein optional component C) is a reducer component and comprises at least one organic solvent d).

2. The clearcoat system according to claim 1 , characterized in that the amount of constituent a3) in component A) is at least 3.0 wt.-%, preferably at least 3.5 wt.-%, more preferably at least 4.0 wt.-%, even more preferably at least 4.5 wt.-%, still more preferably at least 5.0 wt.-%, yet more preferably at least 5.5 wt.-%, even more preferably at least 6.0 wt.-%, still more preferably at least 6.5 wt.-%, most preferably at least 7.0 wt.-%, in each case based on the total weight of component A).220842W001 1 L023824PCT 41 October 7, 2025BASF Coatings GmbH3. The clearcoat system according to claim 1 or 2, characterized in that the at least one kind of fumed silica used as constituent a2) is selected from the group consisting of hydrophilic and hydrophobic fumed silica and mixtures thereof, preferably is selected from the group consisting of hydrophobic fumed silica.

4. The clearcoat system according to one or more of the preceding claims, characterized in constituent a2) is present in component A) in an amount in the range of from 0.10 to 10.0 wt.-%, preferably of from 0.20 to 8.0 wt.-%, more preferably of from 0.30 to 7.0 wt.-%, even more preferably of from 0.40 to 5.0 wt.-%, still more preferably of from 0.50 to 4.0 wt.-%, yet more preferably of from 0.75 to 3.0 wt.-%, based in each case on the total weight of component A).

5. The clearcoat system according to one or more of the preceding claims, characterized in that the average particle size (median) of constituent a2) exceeds the average particle size (median) of constituent a3), preferably by at least 20%, more preferably by at least 30%, still more preferably by at least 50%, and / or in that the average particle size (median) of constituent a2) is in a range of from 4.0 to 200.0 m, preferably of from 10.0 to 150.0 pm, more preferably of from 20.0 to 100.0 pm, still more preferably of from 35.0 to 80.0 pm, yet more preferably of from 45.0 to 70 pm.

6. The clearcoat system according to one or more of the preceding claims, characterized in that the average particle size (median) of constituent a3) is in a range of from 1.0 to 20.0 pm, preferably of from 2.0 to 15.0 pm, more preferably of from 3.0 to 10.0 pm, still more preferably of from 4.0 to 8.0 pm, yet more preferably of from 5.0 to 7.0 pm.

7. The clearcoat system according to one or more of the preceding claims, characterized in that componentA) of the clearcoat system further comprises at least one blocked polyisocyanate as constituent a10), which is different from any of constituents a1) to a3) and optional constituent a4), wherein constituent a10) preferably is present in component A) in an amount in the range of from 1.0 to 35.0 wt.-%, more preferably of from 2.0 to 30.0 wt.-%, still more preferably of from 3.0 to 27.5 wt.-%, even more preferably of from 4.0 to 25.0 wt.-%, still more preferably of from 5.0 to 22.5 wt.-%, yet more preferably of from 7.5 to 20.0 wt.- %, based in each case on the total weight of component A).

8. The clearcoat system according to one or more of the preceding claims, characterized in that in componentB) 5.0 to 80.0 mol-%, preferably 10.0 to 70.0 mol-%, more preferably 15.0 to 60.0 mol-%, still more preferably 20.0 to 50.0 mol-%, yet more preferably 25.0 to 45.0 mol-%, of all originally present isocyanate groups, based on the total molar amount of all originally present isocyanate groups of all isocyanate groups containing constituents present in component B) including constituent b1) and optional constituent b2), have undergone reaction with at least one silane prior to its / their incorporation into component B), preferably to form structural units (I) and / or (II) as defined in claim 9.220842W001 1 L023824PCT 42 October 7, 2025BASF Coatings GmbH9. The clearcoat system according to one or more of the preceding claims, characterized in that the at least one constituent b1) bears at least one structural unit of the formula (I)-NR-(X-SIR"X(OR')3-X) (I), and / or, preferably and, at least one structural unit of the formula (II)-N(X-SiR"x(OR')3-x)n(X'-SiR"y(OR')3-y)m(II), wherein:R = hydrogen, alkyl, cycloalkyl, aryl or aralkyl, it being possible for the carbon chain to be interrupted by nonadjacent oxygen, sulfur or NRagroups, where Ra= alkyl, cycloalkyl, aryl or aralkyl, each R' = independently of one another hydrogen, alkyl or cycloalkyl, it being possible for the carbon chain to be interrupted by nonadjacent oxygen, sulfur or NRagroups, preferably wherein each R' = ethyl and / or methyl, each X,X' = independently of one another linear and / or branched alkylene or cycloalkylene radical having 1 to 20 carbon atoms, preferably wherein each X,X' = alkylene radical having 1 to 4 carbon atoms, each R" = independently of one another alkyl, cycloalkyl, aryl or aralkyl, it being possible for the carbon chain to be interrupted by nonadjacent oxygen, sulfur or NRagroups, preferably wherein each R” = alkyl radical, more particularly having 1 to 6 C atoms, n = parameter of 0 to 2, m = parameter of 0 to 2, m+n = 2, and x, y = parameter of 0 to 2.

10. A clearcoat composition obtainable by mixing at least components A) and B) and optionally C) of the clearcoat system according to one or more of claims 1 to 9 with each other, wherein the clearcoat composition preferably is a solventborne clearcoat composition.

11. The clearcoat composition according to claim 10, characterized in that it is obtainable by mixing components A) and B) in a weight ratio (component A) / component B)) in a range of from 6:1 to 1 :3, more preferably in a range of from 5: 1 to 1 :2, still more preferably in a range of from 4:1 to 1 :1.5, yet more preferably in a weight ratio in a range of from 3.5:1 to 1 : 1.2, still more preferably in a range of from 3.1 : 1 to 1 : 1, most preferably of from 3.1 :1 to 2.5: 1.

12. A method of coating a substrate, comprising at least one step of applying to an optionally pre-coated substrate at least one clearcoat composition according to claim 10 or 11 to form at least one coating film onto the optionally pre-coated substrate and optionally at least one further step of curing the at least one coating film to obtain at least one cured clearcoat layer onto the substrate.220842W001 1 L023824PCT 43 October 7, 2025BASF Coatings GmbH13. The method according to claim 12, characterized in that it is a method of preparing a multilayer coating system onto an optionally pre-coated substrate comprising at least steps 1), 3), and 4), and optionally 2), namely1) applying a first coating composition to an optionally pre-coated substrate and forming a first coating film on the optionally pre-coated substrate,2) optionally applying a second coating composition, which is different from the first coating composition, to the first coating film present on the substrate obtained after step 1) prior to curing the first coating film and forming a second coating film adjacent to the first coating film,3) applying a third coating composition, which is different from the first and the second coating composition, to the first coating film present on the substrate obtained after step 1) prior to curing the first coating film and forming a third coating film adjacent to the first coating film in case optional step 2) is not performed or applying said third coating composition to the second coating film present on the substrate obtained after step 2) prior to curing the second coating film and forming a third coating film adjacent to the second coating film in case optional step 2) is performed, wherein the third coating composition is a clearcoat composition according to claim 10 or 11 , and4) jointly curing the first and third and optionally second coating films, the cured third coating film being the outermost layer of the formed multilayer coating system, to obtain cured first, optionally second, and third coating layers.

14. A coated substrate, which is obtainable by the method according to claim 12 or 13.

15. A multilayer coating system being present on an optionally pre-coated substrate and comprising at least two coatings layers L1 and L3 and optionally at least one coating layer L2 being different from one another, namely a first coating layer L1 applied over at least a portion of an optionally pre-coated substrate, said layer L1 being preferably obtainable from the first coating composition applied in step 1) of claim 13, optionally a second coating layer L2 applied over the first coating layer L1 , said layer L2 being preferably obtainable from the second coating composition applied in optional step 2) of claim 13, and220842W001 1 L023824PCT 44 October 7, 2025BASF Coatings GmbH a third coating layer L3 applied over the first coating layer L1 or, if present, over the second coating layer L2, said layer L3 being obtainable from the clearcoat composition according to claim 10 or 11 .

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