Serial cathodic electrodeposition coating process

Abstract

The present invention relates to a serial cathodic electrodeposition coating process for metallic substrates comprising i. immersing to be coated metallic substrates in an electrodeposition bath comprising an aqueous cathodic electrodeposition coating material, ii. depositing cathodic electrodeposition coating material on the metallic substrates, whereby the deposition process includes connecting the substrates as cathode of a circuit and applying an electric voltage, iii. removing the coated substrates from the electrodeposition bath, and iv. baking the coating material deposited on the metallic substrates.

Description

[0001] 240661 WO01 - Secondary Filing Text - 1 - BASF Coatings GmbH

[0002] Serial cathodic electrodeposition coating process

[0003] The present invention relates to a serial cathodic electrodeposition coating process for metallic substrates, wherein to be coated metallic substrates are immersed in an aqueous cathodic electrodeposition coating material and wherein the cathodic electrodeposition coating material is deposited on the metallic substrates, followed by a specific baking step.

[0004] State of the art

[0005] In the automobile sector, the metallic components used for manufacture must customarily be protected against corrosion. The requirements in terms of the corrosion control to be achieved are very exacting, not least because the manufacturers often offer a guarantee against rust perforation over many years. Such corrosion control is customarily achieved through the coating of the components, or of the substrates used to manufacture them, with at least one coating suitable for that purpose.

[0006] To be able to ensure the necessary corrosion control, it is common practice to apply an electrodeposition coating film to the metallic substrate, this substrate having possibly been pretreated by phosphatizing and / or by other kinds of pretreatments. Electrodeposition coating (electrocoat) materials are coating materials which comprise polymers as binders including optionally crosslinkers, pigments and / or fillers, and, frequently, additives. In general, there are anodically and cathodically depositable electrocoat materials. Cathodically depositable materials have the greatest importance in industrial coating and particularly in automotive finishing. In cathodic electrodeposition coating, the substrates to be coated are immersed into an electrocoating bath and connected as the cathode. The bath has an anode as the counter electrode. The particles of the electrocoating material are stabilized with a positive charge and deposit on the cathode to form a coating film. Following deposition, the coated substrate is removed from the electrocoating bath, rinsed with water and the coating film is baked, i.e., thermally cured. 240661 WO01 - Secondary Filing Text - 2 -

[0007] BASF Coatings GmbH

[0008] Cathodically depositable electrocoat materials are known in the prior art, for example in EP 1 041 125 A1 , DE 197 03 869 A1 and in WO 91 / 09917 A2.

[0009] Besides corrosion protection of the substrate, it is of essential importance that the electrodeposition coating layer produced from the respective electrodeposition coating material constitutes an optimal surface and basis for the application of topcoat materials, for example combinations of primer, basecoat and / or clearcoat materials. As is known, such topcoat materials are applied onto the electrodeposition coating layers for technological and aesthetical purposes and functions. Obviously, the topcoat assemblies thus are mainly applied on the exterior part of respective automotive substrates (bodies) as respective purposes and functions (for example color and / or effect, gloss and / or mechanical functions like stone ship resistance) are relevant mostly or even exclusively for these exterior parts of the substrate.

[0010] For these exterior parts, one further property may be mentioned as key, namely UV stability. To provide for a decent UV stability, the topcoat materials, for example basecoats and clearcoats, regularly contain corresponding additives to provide for prevention of UV-induced deterioration of the overall coating assembly. However, recent technological developments aim for reduction of layer thicknesses and / or additive content of respective topcoat layers (economic and ecological reasons). Therefore, provision of optimal UV stability of an overall coating assembly has become a major challenge, in particular regarding the prementioned technological objectives of, for example, layer thickness reduction. The lack of UV stability may lead to deterioration of not only the topcoat layers, but also the electrocoat layer and ultimately to a major or even complete delamination of the topcoat assembly.

[0011] The above-described effect is even more challenging under real-life conditions in a serial coating plant I process. More particularly, within such a plant and during the curing process of the applied cathodically depositable electrodeposition coating material in industrial ovens, it is virtually impossible to avoid a so-called overbaking process of parts of the applied electrocoat material. Reason is that the complex geometry of automotive bodies means that, on the one hand, comparably thin and 240661 WO01 - Secondary Filing Text - 3 -

[0012] BASF Coatings GmbH heat-exposed substrate regions exist (for example the roof and / or hood of the body), but, on the other hand, other substrate regions with comparably high thickness and lower heat exposure / access are also present. Therefore, to provide for a sufficient heat / energy exposure and thus sufficient curing of the coating material applied onto the latter regions, it is virtually impossible to prevent that coating material applied to the first-mentioned regions are exposed to heat / energy which significantly goes beyond the optimal boundary conditions (so-called overbaking). This, in turn, may lead to certain changes in the condition of the surface of the electrodeposition coating layer. On the other hand and to look onto this aspect from the opposite perspective, in order to not exceed the optimal boundary conditions in the “to-be-overbaked-regions” too much, i.e. in order to avoid a too drastic overbaking, the baking conditions must be chosen in a way that the already mentioned substrate regions with comparably high thickness and lower heat exposure / access may remain below the optimal boundary conditions (i.e. exposed to heat / energy being below the level deemed optimal).

[0013] In total, the whole setup is a balancing act for gaining a sufficient coating quality for all regions of the substrate. In any case, as has been found by the inventors of the here presented invention, the above-described problems in UV stability and delamination of the topcoat assembly from the electrodeposition coating layer are even more pronounced in overbaked regions, while an underbaking in other regions of the substrate of course may result in other performance issues (like, for example, crosslinking density).

[0014] Additionally, it must be considered that the main need of topcoats is given on exterior parts / regions of a substrate, i.e. exactly those regions which are regularly and intensively exposed to UV radiation and likewise are often subject to overbake conditions during curing (e.g. roof and / or hood of the body). Therefore, one major detrimental effect of lack of UV stability (namely delamination of topcoats) is, of all things, most relevant in those substrate regions where the achievement of a high UV stability is most challenging. 240661 WO01 - Secondary Filing Text - 4 - BASF Coatings GmbH

[0015] WO2021 / 239264 A1 discloses an electrocoat material containing a bismuth compound and a specific binder as grinding resin. WO2021 / 239264 A1 aims for an electrocoat material being well curable at comparably low temperatures. Overbaking and any general or specific problem related to overbaking or serial processes in the context of complex substrate geometry and related challenges as mentioned above are not addressed. The same is true for UV stability of coating assemblies.

[0016] Overall and in line with the disclosure of WO2021 / 239264 A1 , it can be said that the prior art does not lie any focus on any specific issues in the context of serial process and baking of electrocoat materials deposited on metallic substrates with complex geometry. Even less, such specific issues were inspected or perceived in connection with UV stability as outlined above.

[0017] Objective

[0018] Of advantage, accordingly, would be an aqueous electrodeposition coating material which, when correspondingly electrodeposited and cured as electrodeposition coating layer, provides for (i) an improved UV stability of multilayer coating assemblies, in particular under overbake conditions (i.e. when the curing / baking of the applied electrodeposition coating material has been performed under such overbake conditions) and also provides for (ii) appropriate further properties, like in particular good corrosions resistance and crosslinking density, in particular in situations where parts of the coated substrate are exposed to the prementioned overbake conditions and where other parts of the same substrate are exposed to baking conditions with comparably low temperature and thus energy. By this means, the number of rejects within the industrial production setup should be significantly reduced. 240661 WO01 - Secondary Filing Text - 5 - BASF Coatings GmbH

[0019] Technical solution

[0020] The objective described above is achieved by the subject-matter claimed in the claims and also by the preferred embodiments of that subject-matter according to the description hereinafter.

[0021] A first subject of the present invention is therefore a serial cathodic electrodeposition coating process for metallic substrates comprising i. immersing to be coated metallic substrates in an electrodeposition bath comprising an aqueous cathodic electrodeposition coating material, ii. depositing cathodic electrodeposition coating material on the metallic substrates, whereby the deposition process includes connecting the substrates as cathode of a circuit and applying an electric voltage, iii. removing the coated substrates from the electrodeposition bath, and iv. baking the coating material deposited on the metallic substrates, wherein the aqueous cathodic electrodeposition coating material comprises at least one aqueous binder dispersion (I) comprising (a) at least one cathodically depositable polymer having functional groups (a1 ) and (b) at least one crosslinking agent having functional groups (b1 ) being complementary to the functional groups (a1 ), meaning that functional groups (a1 ) and (b1 ) are capable to undergo crosslinking reactions, and a pigment paste (II) comprising at least one filler and / or pigment (c), at least one bismuth compound (d) and at least one epoxy-based polymer (e) being different from polymer (a), wherein the epoxy-based polymer (e) comprises at least one epoxy- group containing compound (e1 ) and at least one amine-group containing compound (e2), wherein the amount of bismuth (calculated as metal), based on the total amount of the aqueous cathodically depositable electrodeposition coating material, is at most 0.15 wt.-%, and

[0022] - the baking step iv. involves that parts (i) of individual metallic substrates and corresponding parts of the coating material deposited on individual metallic substrates are heated to a temperature of above 200°C for a duration of at least 10 minutes and other parts (ii) of the same individual metallic substrates and thus corresponding other 240661 WO01 - Secondary Filing Text - 6 - BASF Coatings GmbH parts of the coating material deposited on individual metallic substrates are heated to a temperature between 160 and 190°C for a duration of at least 10 minutes, whereby the parts (ii) are not heated to a temperature of above 190°C during the entire step iv.

[0023] The above-specified process is hereinafter also referred to as process of the invention and accordingly is a subject-matter of the present invention. Preferred embodiments of the process of the invention are apparent from the description hereinafter and also from the dependent claims.

[0024] Another subject-matter of the present invention is a plurality at least partly coated substrate obtained by the inventive method.

[0025] Also, a subject-matter of the present invention is a plurality of articles or components comprising the inventive at least partly coated substrate.

[0026] Detailed description

[0027] The measurement methods to be employed in the context of the present invention for determining certain characteristic variables (parameters) are evident from the Examples section. Unless explicitly indicated otherwise, these measurement methods are to be used for determining the respective characteristic variable in the overall context of the present invention.

[0028] If reference is made in the context of the present invention to an official standard, this of course means the version of the standard that was current on the filing date, or, if no current version exists at that date, then the last current version.

[0029] All film thicknesses reported in the context of the present invention should be understood as dry film thicknesses. It is therefore the thickness of the cured film in each case. Hence, where it is reported that a coating material is applied at a particular film thickness, this means that the coating material is applied in such a way as to result in the stated film thickness after curing. 240661 WO01 - Secondary Filing Text - 7 -

[0030] BASF Coatings GmbH

[0031] Aqueous cathodically depositable electrodeposition coating material to be applied in the process of the invention.

[0032] Within the process of the present invention an aqueous cathodically depositable electrodeposition coating material (aqueous electrocoating material) is to be applied.

[0033] The cathodically depositable aqueous electrodeposition coating material composition comprises at least one binder dispersion (I) comprising at least one cathodically depositable polymer (a) (also named component (a)) having functional groups (a1 ) and at least one crosslinking agent (b) having functional groups (b1 ) being complementary to the functional groups (a1 ), meaning that functional groups (a1 ) and (b1 ) are capable to undergo crosslinking reactions.

[0034] The cathodically depositable aqueous electrodeposition coating material composition thus is suitable for at least partially coating an electrically conductive substrate with an electrodeposition coating composition, meaning that it is suitable for an at least partial application to the substrate surface of an electrically conductive substrate and whose application leads to an electrodeposition coating film (also called layer) onto the surface of the substrate.

[0035] The cathodically depositable electrodeposition coating material composition is aqueous. The term “aqueous” in connection with the electrodeposition coating material composition of the invention is understood preferably for the purposes of the present invention to mean that water, as solvent and / or as diluent, is present as the main constituent of all solvents and / or diluents present in the electrodeposition coating material composition, preferably in an amount of at least 35 wt.-%, based on the total weight of the electrodeposition coating composition of the invention. Organic solvents may be present additionally in smaller proportions, preferably in an amount of < 20 wt.- %.

[0036] The electrodeposition coating composition preferably includes a water fraction of at least 40 wt.-%, more preferably of at least 50 wt.-%, still more preferably of at least 240661 WO01 - Secondary Filing Text - 8 -

[0037] BASF Coatings GmbH

[0038] 60 wt.-%, yet more preferably of at least 65 wt.-%, in particular of at least 70 wt.-%, most preferably of at least 75 wt.-%, based in each case on the total weight of the electrodeposition coating composition.

[0039] The electrodeposition coating composition preferably includes a fraction of organic solvents that is < 10 wt.-%, more preferably in a range of from 0 to < 10 wt.-%, very preferably in a range of from 0 to < 7.5 wt.-% or of from 0 to < 5 wt.-% or of from 0 to 2 wt.-%, based in each case on the total weight of the electrodeposition coating composition. Examples of such organic solvents would 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, ethylene glycol, propylene glycol and butyl glycol ethers and also their acetates, butyl diglycol, diethylene glycol dimethyl ether, cyclohexanone, methyl ethyl ketone, methyl isobutyl ketone, acetone, isophorone, or mixtures thereof. Prominent examples of such organic solvents are, for example, ethylene glycol ethers like butyl glycol or propylene glycol ethers like butoxy propanol or phenoxy propanol.

[0040] The solids content of the electrodeposition coating material composition is preferably in a range of from 5 to 35 wt.-%, more preferably of from 7.5 to 30 wt.-%, very preferably of from 10 to 27.5 wt.-%, more particularly of from 12.5 to 25 wt.-%, most preferably of from 15 to 22.5 wt.-% or of from 15 to 20 wt.-%, based in each case on the total weight of the electrodeposition coating composition. The solids content, in other words the nonvolatile fraction, is determined in accordance with the method described hereinafter.

[0041] The electrodeposition coating material composition preferably has a pH in the range of from 2.0 to 10.0, more preferably in the range of from 2.5 to 9.5 or in the range of from 2.5 to 9.0, very preferably in the range of from 3.0 to 8.5 or in the range of from 3.0 to 8.0, more particularly in the range of from 2.5 to 7.5 or in the range of from 3.5 to 7.0, especially preferably in the range of from 4.0 to 6.5, most preferably in the range of from 3.5 to 6.5 or of from 5.0 to 6.0. 240661 WO01 - Secondary Filing Text - 9 -

[0042] BASF Coatings GmbH

[0043] The electrodeposition coating material includes component (a) preferably in an amount in a range of from 15 to 85 wt.-%, more preferably of from 20 to 80 wt.-%, very preferably of from 25 to 77.5 wt.-%, more particularly of from 30 to 75 wt.-% or of from 35 to 75 wt.-%, most preferably of from 40 to 70 wt.-% or of from 45 to 70 wt.-% or of from 50 to 70 wt.-%, based in each case on the total solids content of the electrodeposition coating composition. Alternatively, the electrodeposition coating material composition of the invention includes component (a) preferably in an amount in a range of from 1 to 80 wt.-%, more preferably of from 2.5 to 75 wt.-%, very preferably of from 5 to 70 wt.-%, more particularly of from 7.5 to 65 wt.-%, most preferably of from 8 to 60 wt.-% or of from 10 to 50 wt.-%, based in each case on the total weight of the electrodeposition coating material, respectively the coating bath.

[0044] The electrodeposition coating material composition additionally includes at least one crosslinking agent component (b), said component (b) is preferably present in an amount in the range of from 5 to 45 wt.-%, more preferably of from 6 to 42.5 wt.-%, very preferably of from 7 to 40 wt.-%, more particularly of from 8 to 37.5 wt.-% or of from 9 to 35 wt.-%, most preferably of from 10 to 35 wt.-%, especially preferably of from 15 to 35 wt.-%, based in each case on the total solids content of the electrodeposition coating composition. Alternatively, said component (b) is preferably present in an amount in a range of from 0.5 to 30 wt.-%, more preferably of from 1 to 25 wt.-%, very preferably of from 1.5 to 20 wt.-%, more particularly of from 2 to 17.5 wt.-%, most preferably of from 2.5 to 15 wt.-%, especially preferably of from 3 to 10 wt.-%, based in each case on the total weight of the electrodeposition coating material composition, respectively the coating bath.

[0045] The fractions in wt.-% of all of the components (a), (b) and water included in the electrodeposition coating composition of the invention, and also of further components that may be present additionally, add up to 100 wt.-%, based on the total weight of the electrodeposition coating material composition.

[0046] The relative weight ratio of components (a) and (b) to one another in the electrodeposition coating material composition is preferably in a range of from 5:1 to 240661W001 - Secondary Filing Text - 10 -

[0047] BASF Coatings GmbH

[0048] 1.1 :1 , more preferably in a range of from 4.5:1 to 1.1 :1 , very preferably in a range of from 4:1 to 1.2:1 , more particularly in a range of from 3:1 to 1.5:1.

[0049] The composition comprises at least one, preferably exactly one, binder dispersion (I). As known to the person skilled in the art, electrodeposition coating compositions regularly contain such a binder dispersion, i.e. an aqueous dispersion comprising at least one polymer as binder. Also, the composition contains at least one pigment paste (II). Again, as known by the skilled person in the art, electrodeposition coating compositions regularly contain such pigment pastes.

[0050] In the following, different essential and optional components of the compositions are described. More details on the binder dispersions (I) and pigment pastes (II) will also follow further below.

[0051] Component (a)

[0052] Component (a) is at least one cathodically depositable polymer, which preferably functions as at least one binder in the electrodeposition coating material composition.

[0053] Any polymer is suitable as binder and thus as component (a) as long as it is cathodically depositable. Preferred are poly(meth)acrylates, (meth)acrylate copolymers, and epoxide polymers.

[0054] Preferably, component (a) of the electrodeposition coating composition comprises and / or is at least one epoxide-amine adduct.

[0055] An epoxide-amine adduct is a reaction product of at least one epoxy resin and at least one amine. Epoxy resins used are more particularly those based on bisphenol A and / or derivatives thereof. Amines reacted with the epoxy resins are primary and / or secondary amines or salts thereof and / or salts of tertiary amines. 240661 WO01 - Secondary Filing Text - 11 -

[0056] BASF Coatings GmbH

[0057] The at least one epoxide-amine adduct used as component (a) is preferably a cationic, epoxide-based and amine-modified resin. The preparation of such cationic, am inemodified, epoxide-based resins is known and is described for example in DE 35 18 732, DE 35 18 770, EP 0 004 090, EP 0 012 463, EP 0 961 797 B1 , and EP 0 505 445 B1. Cationic, epoxide-based, amine-modified resins are understood preferably to be reaction products of at least one polyepoxide having preferably two or more, e.g., three, epoxide groups, and at least one amine, preferably at least one primary and / or secondary amine. Particularly preferred polyepoxides are polyglycidyl ethers of polyphenols that are prepared from polyphenols and epihalohydrins. Polyphenols used may in particular be bisphenol A and / or bisphenol F. Other suitable polyepoxides are polyglycidyl ethers of polyhydric alcohols, such as, for example, of ethylene glycol, diethylene glycol, triethylene glycol, propylene 1 ,2-glycol, propylene 1 ,4-glycol, 1 ,5-pentanediol, 1 ,2,6-hexanetriol, glycerol, and 2,2-bis(4- hydroxycyclohexyl)propane. The polyepoxide used may also be a modified polyepoxide. Modified polyepoxides are understood to be those polyepoxides in which some of the reactive functional groups have been reacted with at least one modifying compound. Examples of such modifying compounds are as follows: i) compounds containing carboxyl groups, such as saturated or unsaturated monocarboxylic acids (e.g., benzoic acid, linseed oil fatty acid, 2-ethylhexanoic acid, Versatic acid), aliphatic, cycloaliphatic and / or aromatic dicarboxylic acids of various chain lengths (e.g., adipic acid, sebacic acid, isophthalic acid, or dimeric fatty acids), hydroxyalkyl carboxylic acids (e.g., lactic acid, dimethylolpropionoic acid), and carboxyl-containing polyesters, or ii) compounds containing amino groups, such as diethylamine or ethylhexylamine or diamines with secondary amino groups, e.g., N,N'-dialkylalkylenediamines, such as dimethylethylenediamine, N,N'-dialkyl-polyoxyalkyleneamines, such as N,N'- dimethylpolyoxypropylenediamine, cyanoalkylated alkylenediamines, such as bis- N,N'-cyanoethylethylenediamine, cyanalkylated polyoxyalkyleneamines, such as bis- N,N'-cyanoethylpolyoxypropylenediamine, polyaminoamides, such as, for example, Versamides, especially amino-terminated reaction products of diamines (e.g., hexamethylenediamine), polycarboxylic acids, especially dimer fatty acids and 240661 WO01 - Secondary Filing Text - 12 -

[0058] BASF Coatings GmbH monocarboxylic acids, more particularly fatty acids, or the reaction product of one mole of diaminohexane with two moles of monoglycidyl ether or monoglycidyl ester, especially glycidyl esters of a-branched fatty acids, such as Versatic acid, or iii) compounds containing hydroxyl groups, such as neopentyl glycol, bisethoxylated neopentyl glycol, neopentyl glycol hydroxypivalate, dimethylhydantoin-N,N'-diethanol, hexane-1 ,6-diol, hexane-2,5-diol, 1 ,4-bis(hydroxymethyl)cyclohexane, 1 ,1 -iso- propylidenebis(p-phenoxy)-2-propanol, trimethylolpropane, pentaerythritol or amino alcohols, such as triethanolamine, methyldiethanolamine, or hydroxyl-group- containing alkylketimines, such as aminomethylpropane-1 ,3-diol methylisobutylketimine or tris(hydroxymethyl)aminomethane cyclohexanoneketimine, and also polyglycol ethers, polyester polyols, polyether polyols, polycaprolactone polyols, polycaprolactam polyols of various functionalities and molecular weights, or iv) saturated or unsaturated fatty acid methyl esters, which are esterified with hydroxyl groups of the epoxy resins in the presence of sodium methoxide.

[0059] Examples of amines which can be used for preparing component (a) are mono- and dialkylamines, such as methylamine, ethylamine, propylamine, butylamine, dimethylamine, diethylamine, dipropylamine, methylbutylamine, alkanolamines, such as methylethanolamine or diethanolamine, dialkylaminoalkylamines, such as dimethylaminoethylamine, diethylaminopropylamine, or dimethylaminopropylamine, for example. The amines which can be used may also include other functional groups as well, provided they do not disrupt the reaction of the amine with the epoxide group of the optionally modified polyepoxide and also do not lead to gelling of the reaction mixture. Secondary amines are preferably used. The charges that are needed for dilutability with water and for electrical deposition may be generated by protonation with water-soluble acids (e.g., boric acid, formic acid, acetic acid, lactic acid, alkylsulfonic acids (e.g. methanesulfonic acid)); preferably acetic acid and / or formic acid). A further way of introducing cationic groups into the optionally modified polyepoxide is to react epoxide groups of the polyepoxide with amine salts. 240661 WO01 - Secondary Filing Text - 13 - BASF Coatings GmbH

[0060] The epoxide-amine adduct which can be used as component (a) is preferably a reaction product of an epoxy resin based on bisphenol A and primary and / or secondary amines or salts thereof and / or the salt of a tertiary amine.

[0061] The polymer (a) has functional groups (a1 ) being capable to undergo crosslinking reactions with functional groups (b1 ) as described below. It is evident that such functional groups (a1 ) preferably are those functional groups being inherently present after preparation of the above-described polymers based on the likewise abovedescribed reactants. Accordingly, preferred functional groups are hydroxyl groups and amino groups.

[0062] Component (b)

[0063] At least one crosslinking agent is present in the binder dispersion (I) of the electrodeposition coating material composition as component (b), which is preferably selected from the group consisting of blocked polyisocyanates, free polyisocyanates, amino resins, and mixtures thereof. Said component (b) is different from component (a).

[0064] 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, so that the blocked polyisocyanate formed is stable in particular with respect to hydroxyl groups and 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.

[0065] In the preparation of the blocked polyisocyanates it is possible to use any desired organic polyisocyanates suitable for crosslinking. Isocyanates used preferably are 240661 WO01 - Secondary Filing Text - 14 -

[0066] BASF Coatings GmbH

[0067] (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-dimethyloctane, dodecane 1 ,12-diisocyanate, co,co'-di- isocyanatodipropyl ether, cyclobutene 1 ,3-diisocyanate, cyclohexane 1 ,3- and 1 ,4- diisocyanate, 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (isophorone diisocyanate, I P D 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'-diisocyanato-2,2',3,3',5,5',6,6'- octamethyldicyclohexylmethane, co,co'-diisocyanato-1 ,4-diethylbenzene, 1 ,4-di- isocyanatomethyl-2,3,5,6-tetramethylbenzene, 2-methyl-1 ,5-diisocyanatopentane (MPDI), 2-ethyl-1 ,4-diisocyanatobutane, 1 ,10-diisocyanatodecane, 1 ,5-diiso- cyanatohexane, 1 ,3-diisocyanatomethylcyclohexane, 1 ,4-diiso- cyanatomethylcyclohexane, 2,5(2,6)-bis(isocyanatomethyl)bicyclo[2.2.1 ]heptane

[0068] (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.

[0069] For the blocking of the polyisocyanates it is possible with preference to use any desired suitable aliphatic, cycloaliphatic, 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 240661 WO01 - Secondary Filing Text - 15 - BASF Coatings GmbH alcohols, such as cyclopentanol and cyclohexanol; 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.

[0070] Tris(alkoxycarbonylamino)-1 ,3,5-triazine (TACT) are likewise known to the skilled person. The use of tris(alkoxycarbonylamino)-1 ,3,5-triazines as crosslinking agents in coating material compositions is known. For example, DE 197 12 940 A1 describes the use of such crosslinking agents in basecoat materials. U.S. patent No. 5,084,541 describes the preparation of corresponding compounds which can be used as component (c). Such triazines are for the purposes of the present invention to be encompassed by the term “blocked polyisocyanates”.

[0071] Amino resins (am inoplast resins) are likewise known to the skilled person. Amino resins used are preferably melamine resins, more particularly melamine-formaldehyde resins, which are likewise known to the skilled person. Preference, however, is given to using no amino resins such as melamine-formaldehyde resins as crosslinking agents (c). The electrodeposition coating material composition of the invention therefore preferably comprises no amino resins such as melamine-formaldehyde resins.

[0072] The electrodeposition coating material composition is used preferably as a one- component (1 K) coating composition. For this reason, the electrodeposition coating composition preferably contains no free polyisocyanates.

[0073] The crosslinking agent (b) has functional groups (b1 ) being capable to undergo crosslinking reactions with functional groups (a1 ) as described above. It is evident that such functional groups (b1 ) preferably are blocked isocyanate groups.

[0074] Pigments and / or fillers (c) 240661 WO01 - Secondary Filing Text - 16 -

[0075] BASF Coatings GmbH

[0076] The electrodeposition coating material composition comprise at least one pigment and / or at least one filler (c).

[0077] The term “pigment” is known to the skilled person, from DIN 55943 (date: October 2001 ), for example. A “pigment” in the sense of the present invention refers preferably to a component in powder or flake form which is substantially, preferably entirely, insoluble in the medium surrounding them, such as the electrodeposition coating material composition of the invention, for example. Pigments are preferably colorants and / or substances which can be used as pigment on account of their magnetic, electrical and / or electromagnetic properties. Pigments differ from “fillers” preferably in their refractive index, which for pigments is > 1 .7.

[0078] The term “filler” is known to the skilled person, from DIN 55943 (date: October 2001 ), for example. “Fillers” for the purposes of the present invention preferably are components, which are substantially, preferably entirely, insoluble in the application medium, such as the electrodeposition coating material composition of the invention, for example, and which are used in particular for increasing the volume. “Fillers” in the sense of the present invention preferably differ from “pigments” in their refractive index, which for fillers is < 1 .7.

[0079] Any customary pigment known to the skilled person may be used. Examples of suitable pigments are inorganic and organic coloring pigments. Examples of suitable inorganic coloring pigments are white pigments such as titanium dioxide, zinc white, zinc sulfide or lithopone; black pigments such as carbon black, iron manganese black or spinel black; chromatic pigments such as chromium oxide, chromium oxide hydrate green, cobalt green or ultramarine green, cobalt blue, ultramarine blue or manganese blue, ultramarine violet or cobalt violet and manganese violet, red iron oxide, cadmium sulfoselenide, molybdate red or ultramarine red; brown iron oxide, mixed brown, spinel phases and corundum phases or chromium orange; or yellow iron oxide, nickel titanium yellow, chromium titanium yellow, cadmium sulfide, cadmium zinc sulfide, chromium yellow or bismuth vanadate. Further inorganic coloring pigments are silicon dioxide, aluminum oxide, aluminum oxide hydrate, especially boehmit, titanium 240661 WO01 - Secondary Filing Text - 17 -

[0080] BASF Coatings GmbH dioxide, zirconium oxide, cerium oxide, and mixtures thereof. Examples of suitable organic coloring pigments are monoazo pigments, disazo pigments, anthraquinone pigments, benzimidazole pigments, quinoacridone pigments, quinophthalone pigments, diketopyrrolopyrrol pigments, dioxazine pigments, indanthrone pigments, isoindoline pigments, isoindolinone pigments, azomethine pigments, thioindigo pigments metal complex pigments, perinone pigments, perylene pigments, phthalocyanine pigments or aniline black.

[0081] Any customary filler known to the skilled person may be used. Examples of suitable fillers are kaolin, dolomite, calcite, chalk, calcium sulfate, barium sulfate, graphite, silicates such as magnesium silicates, especially corresponding phyllosilicates such as hectorite, bentonite, montmorillonite, talc and / or mica, silicas, especially fumed silicas, hydroxides such as aluminum hydroxide or magnesium hydroxide. As examples of kaolin, commercial products like ASP 200 (non-calcined kaolin, Fa. BASF) or KaMin 2000C (calcined kaolin, Fa. KaMin) may be mentioned (with a preference on ASP 200). Also, organic fillers such as textile fibers, cellulose fibers, polyethylene fibers or polymer powders may be applied. For further details, reference is made to Rdmpp Lexikon Lacke und Druckfarben, Georg Thieme Verlag, 1998, pages 250 ff. , “Fillers”.

[0082] The pigment plus filler content, based on the total weight of the electrodeposition material coating composition of the invention, is preferably in the range of from 0.1 to 20.0 wt.-%, more preferably of from 0.1 to 15.0 wt.-%, very preferably of from 0.1 to 10.0 wt.-%, especially preferably of from 0.1 to 5.0 wt.-%, and more particularly of from 0.1 to 2.5 wt.-%.

[0083] The pigment and / or filler (c) is incorporated in the form of a pigment paste (II) into the electrodeposition coating material composition. It is possible and preferred that one pigment paste (II) comprises both one or more pigments and / or fillers. Such pastes include at least one polymer used as grinding resin, namely at least one epoxy-based polymer (e) (described below in more detail). The polymer(s) used as grinding resin preferably have building blocks which interact with the surfaces of the pigments / fillers. 240661W001 - Secondary Filing Text - 18 -

[0084] BASF Coatings GmbH

[0085] The grinding resins therefore preferably have the effect of an emulsifier. Besides the grinding resins, further customary additives like wetting agents or dispersants (optional components (e) as described below) and also solvents (water and organic co-solvents) may be comprised. The production of the pigment paste regularly includes a grinding / m illing step. Thereby, the pigments and / or fillers are preferably ground together with a grinding resin and the further components / solvents to form a pigment paste. To produce the finished electrodeposition coating material composition, this paste is mixed with the rest of the constituents, in particular the binder dispersion (I). The use of a pigment paste leads advantageously to a greater flexibility in electrodeposition coating, since the pigment / filler and binder of the electrodeposition coating material composition can be readily adapted at any time to the requirements of practice via the amount of the pigment paste.

[0086] Bismuth compound (d)

[0087] The electrodeposition coating material composition of the invention includes, within the pigment paste, as component (d) at least one bismuth compound (also called bismuth containing compound). Preferably, the bismuth compound is introduced before the above-described grinding / m illing step for paste production to ensure an appropriate integration and effectiveness of the respective catalyst. Therefore, preferably, the bismuth compound (d) is introduced into the inventive aqueous electrocoating material by grinding said compound (d) in the presence of a grinding resin, preferably below described polymer (e).

[0088] The bismuth compound serves as a catalyst for the crosslinking reaction as described above (functional groups (a1 ) and (b1 )). Examples of such bismuth compounds (d) are bismuth(lll) oxide, basic bismuth(lll) oxide, bismuth(lll) hydroxide, bismuth(lll) carbonate, bismuth(lll) nitrate, bismuth(lll) subnitrate (basic bismuth(lll) nitrate), bismuth(lll) salicylate and / or bismuth(lll) subsalicylate (basic bismuth(lll) salicylate), and also mixtures thereof. Especially preferred are water-insoluble, bismuth-containing catalysts. Preferred more particularly is bismuth(lll) subnitrate. The bismuth subnitrate preferably has the empirical formula 4(BiNO3(OH)2)BiO(OH). Bismuth subnitrate is a 240661 WO01 - Secondary Filing Text - 19 - BASF Coatings GmbH commercially available compound and is sold, for example, by the company MCP HEK GmbH, Lubeck, Germany.

[0089] The electrodeposition coating material composition of the invention preferably includes the at least one bismuth-compound in an amount such that the bismuth(lll) content, calculated as bismuth metal, based on the total weight of the electrodeposition coating material of the invention, is in a range from 10 ppm to 20 000 ppm. The amount of bismuth, calculated as metal, may be determined by means of inductively coupled plasma-atomic emission spectrometry (ICP-OES) in accordance with DIN EN ISO 11885 (date: September 2009).

[0090] While the existence of a respective bismuth compound is essential within the context of the present invention, the inventors surprisingly found that a pronounced effect on UV stability under overbake conditions as outlined in the introductory part requires that the content of bismuth does not exceed a certain level. More particularly, the bismuth content, calculated as metal, preferably does not exceed 1500 ppm (0.15 wt.-%), based on the total weight of the electrodeposition coating material. Even more preferably, the bismuth content, calculated as metal, does not exceed 1400 ppm (0.14 wt.-%) or 1300 ppm (0.13 wt.-%), based on the total weight of the electrodeposition coating material. e

[0091] The electrodeposition coating material composition comprises as further mandatory component (e) at least one epoxy-based polymer being different from polymer (a), wherein the epoxy-based polymer (e) comprises at least one epoxy- group containing compound (e1 ) and at least one amine-group containing compound (e2). Comprising, in this context, quite obviously means that the respective compounds (e1 ) and (e2) are comprised in the polymer (e) in reacted form, i.e. being applied as reactants in the synthesis of the polymer (e). Also, from the above, it is evident that the polymer (a) described above may also contain an epoxy-group containing compound and also an amine-group containing compound. The wording “being different from polymer (a)” just clarifies that in any case two different polymers (i.e. polymer (a) and polymer (e)) are 240661 WO01 - Secondary Filing Text - 20 - BASF Coatings GmbH contained in the inventive composition, even if these two polymers may be of similar structure and chemistry.

[0092] Preferably, the amine-group containing compound (e2) contains both an amine-group and a hydroxy group. Also, preferably, the amine group is a primary amine group.

[0093] Preferably, compound (e2) has the general formula (I)

[0094] R1R2N-(CH2)a-O-[CH2-CH(R3)]b-OH (I) wherein

[0095] R1, R2independently from each other, are selected from hydrogen or a C1-C4 alkyl residue;

[0096] R3is selected from hydrogen or a C1-C4 alkyl residue; a is an integral number of 1 to 8; and b is an integral number of 1 to 4,

[0097] As particularly preferred compounds (e2) of general formula (I) comprise a primary amino group, residues R1and R2in general formula (I) favorably are selected from hydrogen. Also, residue R3in general formula (I) is preferably selected from hydrogen. Parameter a in general formula (I) is preferably an integral number of 1 to 6, preferably 1 to 4, very preferably 2. Parameter b in general formula (I) is preferably an integral number of 1 to 3, preferably 1 to 2, very preferably 1 . A particularly preferred compound (e2) of general formula (I) is therefore H2N-(CH2)2-O-[CH2-CH2]-OH or 2-(2- aminoethoxy)ethanol.

[0098] It is preferred that the molar ratio of the at least one compound (e2) and the at least one compound (e1 ) is at least 1 :2.5 (= 0.4), for example from 1 :2.5 to 1 : 1 (=0.4 to 1 .0). It has been found that such comparably high amounts of compound (e2) may serve for an increased catalyzing effect of the crosslinking reaction between compounds (a) and (b), meaning that the crosslinking density of the cured electrocoat material is enhanced. In other words and without wanting to be bound to any theory: The respective polymer (e) may serve for an higher amount of bismuth being available for catalyzing crosslinking, for example by providing for a higher amount of solubilized (or 240661 WO01 - Secondary Filing Text - 21 -

[0099] BASF Coatings GmbH at least finely distributed / dispersed and thus active) bismuth. Surprisingly, while this contributes to a sufficient crosslinking density of electrocoat material also at lower curing temperature (substrate temperature, cf. introductory part), it does still provide for appropriate surface conditions at overbake conditions in terms of UV stability, in particular in combination of comparably low contents of bismuth (calculated as metal) as defined as preferred embodiments above.

[0100] The at least one polymer (e) being different from polymer (a) described in detail above preferably is obtained by reacting compound (e1 ) with compound (e2), more preferably also with compound (e3) and optionally (e4), namely: at least one compound (e1 ) containing at least one epoxy group with at least one specific compound (e2) and at least one hydroxy group containing compound (e3), and optionally at least one compound (e4) comprising at least one primary and at least one tertiary amino group, with the proviso that the molar ratio of the at least one specific compound (e2) to the at least one compound (e1 ) is at least 1 : 2.5.

[0101] Component (e1 ) can be any compound containing at least one reactive epoxide group. Said compound (e1 ) preferably has an epoxide equivalent weight (EEW) of below 1 ,000 g / Eq., more preferably below 500 g / Eq., very preferably of 160 to 450 mol / Eq..

[0102] Particularly preferred epoxide compounds are polyphenol diglycidyl ethers prepared from polyphenols and epihalohydrins. Examples of polyphenols which can be employed are bisphenol A, bisphenol F, 1 ,1 -bis(4-hydroxyphenyl)-n-heptane, 4,4- dihydroxybenzophenone, bis(4-hydroxyphenyl)-1 , 1 -ethane, bis(4-hydroxyphenyl)-1 , 1 - isobutane, bis(4-hydroxy-tert-butylphenyl)-2,2-propane, bis(2-hydroxynaphthyl)- methane, 1 ,5-dihydroxynaphthalene and phenolic novolak resins. Particular suitable polyphenols are selected from bisphenol A, bisphenol F and 1 ,1 -bis(4-hydroxyphenyl)- n-heptan. 240661 WO01 - Secondary Filing Text - 22 -

[0103] BASF Coatings GmbH

[0104] Further preferred epoxide compounds are diglycidyl ethers of polyhydric alcohols, such as ethylene glycol, diethylene glycol, triethylene glycol, 1 ,2-propylene glycol, 1 ,4- propylene glycol, 1 ,5-pentanediol, 1 ,2,6-hexanetriol, glycerol and bis(4- hydroxycyclohexyl)-2,2-propane. It is also possible to use diglycidyl esters of polycarboxylic acids, such as, for example, oxalic acid, succinic acid, glutaric acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, dimerized linolenic acid, etc. Typical examples are glycidyl adipate and glycidyl phthalate. Also suitable are hydantoin epoxides, epoxidized polybutadiene and diepoxide compounds obtained by epoxidation of an olefinically unsaturated alicyclic compound.

[0105] It is particularly preferred if at least two different compounds (e1 -1 ) and (e1 -2), very preferably exactly two compounds (e1 -1 ) and (e1 -2), are reacted with compounds (e2) to (e4). Said different compounds (e1 -1 ) and (e1 -2) both comprise at least one epoxy group but preferably differ in their epoxy equivalent weight (EEW).

[0106] The compound (e1 -1 ) preferably has an epoxy equivalent weight of 160 to 250 g / Eq., more preferably 170 to 220 g / Eq., very preferably 180 to 200 g / Eq., while compound (e1 -2) preferably has a higher epoxy equivalent weight of 350 to 450 g / Eq., more preferably 360 to 430 g / Eq., very preferably 370 to 410 g / Eq.. Suitable compounds (e1 - 1 ) are, for example, high viscosity liquid epoxy resin based on bisphenol A diglycidyl ether having an epoxy equivalent of 184 to 190 g / Eq. (ISO3001 ) and a viscosity of 12,000 to 14,000 mPa*s (ISO 12058-1 , 25 °C, falling ball). Suitable compounds (e1 -2) are, for example, polypropylenglycol diglycidyl ethers with an epoxy equivalent of 385 to 405 g / Eq. (ISO3001 ) and a viscosity of 42 to 52 mPa*s (ISO 12058-1 , 25 °C, falling ball).

[0107] Compounds (e1 -1 ) and (e1 -2) are preferably used in specific molar ratios of (e1 -1 ) to (e1 -2) of 2 : 1 to 1 : 2, more preferably 1.8 : 1 , very preferably 1.8 : 1.4.

[0108] Component (e3) contains at least one hydroxy group and is preferably selected from aromatic or aliphatic compounds. It is particularly preferred if component (e3) contains exactly one hydroxy group and reacts in a monofunctional manner with respect to epoxide groups of compound (e1 ). Component (e3) is preferably a compound R4-OH, 240661 WO01 - Secondary Filing Text - 23 - BASF Coatings GmbH where R4is preferably a residue of general formula (IV) with R5being H, C1-C20 alkyl, preferably t-butyl, nonyl or dodecyl, or a residue R6-O-* with R6being C1-C10 alkyl, preferably methyl or HO-(CHR7CH2-O)n-CHR7CH2-* where n = 0 to 10 and R7= hydrogen or methyl. The symbol * denotes the connection of the respective residue to the compound R4-OH or to the residue of general formula (IV).

[0109] Especially suitable compounds (e3) are thus monophenols, diphenols, for example bisphenol A, or a mixture of mono- and diphenols. A particularly suitable compound is the aromatic hydroxy compound 4-dodecyl phenol.

[0110] Optional compound (e4) comprises at least one primary and at least one tertiary amine group. Said compound (e4) should preferably be a water-soluble compound. Examples of such amines are dialkylaminoalkylamines, such as, for example, dimethylaminoethylamine, diethylamino propylamine, dimethylaminopropylamine and the like. In most cases, low-molecular-weight amines are used, but it is also possible to use relatively high-molecular-weight monoamines. A particularly preferred compound (e4) is selected from 3-(dimethylamino)-1 -propylamine.

[0111] Polyamines containing primary and tertiary amino groups can be reacted with the epoxides in the form of their ketimines. The ketimines are prepared from the polyamines in a known manner.

[0112] The charges which are necessary for water-dilutability and electrodeposition of polymer (e) can be generated by protonation by means of water-soluble acids (for example boric acid, formic acid, lactic acid, propionic acid, butyric acid, carbonic acid or preferably acetic acid) or alternatively by reaction of the oxirane groups with salts of an amine or a sulfide / acid or phosphine / acid mixture. The salt of an amine is preferably the salt of a tertiary amine. Preferred amines are tertiary amines, such as dimethyl ethanolamine, triethylamine, trimethylamine, tripropyl amine and the like. 240661 WO01 - Secondary Filing Text - 24 -

[0113] BASF Coatings GmbH

[0114] Through addition of catalysts, preferably phosphine or a phosphine derivative or phosphine salt, the reaction of the above-mentioned components can be controlled in such a way that only phenolic hydroxyl groups, but not secondary hydroxyl groups which might be present in component (e3), react with epoxide groups. The phosphine used can be any desired phosphine containing no interfering groups. Examples of such phosphines are aliphatic, aromatic or alicyclic phosphines, specific examples of such phosphines which may be mentioned being the following: lower trialkylphosphines, such as trimethylphosphine, triethylphosphine, tripropylphosphine, tributyl phosphine, mixed lower alkylphenylphosphines, such as phenyldimethylphosphine, phenyldiethylphosphine, phenyldipropylphosphine, diphenylmethylphosphine, di phenylethylphosphine, diphenylpropylphosphine, tri phenylphosphine, alicyclic phosphines, such as tetra methyleneethylphosphine and the like.

[0115] Thus, it is preferred if a catalyst, preferably triphenyl phosphine, is used to prepare the at least one polymer (e).

[0116] A particularly preferred polymer (e) is obtained by reacting:

[0117] - a compound (e1 -1 ) having an epoxy equivalent weight of 180 to 200 g / Eq. and a one compound (e1 -2) having an epoxy equivalent weight of 370 to 410 g / Eq. with

[0118] - at least one hydroxy group containing compound (e3), said compound (e3) being selected from aromatic hydroxy compounds, preferably 4-dodecyl phenol and

[0119] - at least one compound (e2) of general formula (I)

[0120] R1R2N-(CH2)a-O-[CH2-CH(R3)]b-OH (I) wherein

[0121] R1and R2are selected from hydrogen,

[0122] R3is selected from hydrogen, a is an integral number of 1 to 6, preferably 1 to 4, very preferably 2, and b is an integral number of 1 to 3, preferably 1 to 2, very preferably 1 and 240661 WO01 - Secondary Filing Text - 25 - BASF Coatings GmbH

[0123] - at least one compound (e4) comprising at least one primary and at least one tertiary amino group, preferably 3-(dimethylamino)-1 -propylamine, wherein the molar ratio of the at least one compound (e2) of general formula (I) to the compounds (e1-1 ) and (e1-2) is greater than 1 : 2, like for example 1 :1.49. The molar ratio is in this case calculated by using the total molar amount of compounds (e1 -1 ) and (e1 -2) as well as the total molar amount of compound (e2).

[0124] In a further preferred embodiment, the fraction of compound (e2) is at least 5 wt.-%, preferably at least 6.5 wt.-% or even more preferably at least 8 wt.-%, in each case based on the overall weight of the epoxy-based polymer (e). The overall weight of the epoxy-based polymer (e), in this calculation, quite obviously means the sum of raw materials (i.e. compounds like, for example, monomers (e1 ), (e2), (e3) and (e4)) applied for production for the polymer (e).

[0125] Further com

[0126] Additionally, the electrocoat materials may further comprise at least one customary and known additive selected from the group consisting of plasticizers, catalysts other than bismuth compound (d); anticrater additives; polyvinyl alcohols; polyvinylethers; dendritic polyethers or polyesters; polyurea resins; polyetheramine microgels; polyurethane microgels; polyurethanes; thermally curable reactive diluents; molecularly dispersedly soluble dyes; light stabilizers, such as UV absorbers and reversible free-radical scavengers (HALS); antioxidants; low-boiling and high-boiling (“long”) organic solvents; devolatilizers; wetting agents; emulsifiers; slip additives; polymerization inhibitors; thermolabile free-radical initiators; adhesion promoters; leveling agents; film-forming auxiliaries; flame retardants; corrosion inhibitors; flow aids; waxes; siccatives; biocides, and flatting agents. The additive content may vary very widely according to intended use. The amount, based on the total weight of the aqueous electrocoating material, is p 0.1 to 20 wt.%, more preferably 0.1 to 15 wt.%, very preferably 0.1 to 10 wt.%, especially preferably 0.1 to 5 wt.%, and more particularly 0.1 to 2.5 wt.%. 240661 WO01 - Secondary Filing Text - 26 -

[0127] BASF Coatings GmbH

[0128] The aqueous electrocoating material preferably has a nonvolatile fraction, in other words a solids content, in a range from 10 to 30 wt.%, preferably 15 to 25 wt.%, based in each case on the total weight of the electrocoating material. Methods for determining the solids content are known to the skilled person. The solids content is determined as stated in the experimental section below.

[0129] Within the context of the present invention, it is preferred that the aqueous cathodically depositable electrodeposition coating material is further characterized in that a baked electrodeposition coating layer produced from the material on a steel substrate (for example a zinc-phosphatized steel substrate) (electric oven, 170°C substrate temperature, 15 minutes) has a surface energy of at least 50 mJ / m2(Measurement method outlined in more detail in the example section being valid also in the overall context of the present invention). This feature and corresponding technical adaption of electrocoat material may contribute to the technical advantages described in the introductory part, in particular good UV stability under overbaking conditions.

[0130] While it was surprising that exactly this character and adaption of electrocoat materials contributeto the described technical advantages, it may be mentioned that the person skilled in the art does know how this adaption may be realized (i.e. how the surface energy may be increased or decreased). Quite obviously, the exact composition and characteristics of individual compounds I raw materials play a major role. As an example, it may be described that certain additive compounds may influence the surface energy. For example, addition (or omission) of certain plasticizers (and variation in amounts of such plasticizers) may vary and thus be used to adapt the surface energy in a target-oriented manner. Depending on the chemistry and thus physiochemical properties of the additives, these additions / omissions / variations then lead to the desired outcome.

[0131] As an example, well-known plasticizers in electrocoat applications are ethoxylated bisphenol A compounds, for example bisphenol A ethoxylated with 2 to 20, like 4 to 12 ethylene oxide units on average, for example bisphenol A 6EO (i.e. bisphenol A ethoxylated with 6 equivalents of ethylene oxide on average, i.e. 3 respective units on either side of the bisphenol A on average). Reduction of the amount of such plasticizer 240661 WO01 - Secondary Filing Text - 27 -

[0132] BASF Coatings GmbH may lead to an increase in surface energy. For example, in one embodiment it is preferred that the amount of ethoxylated bisphenol A, more particularly bisphenol A 6EO, does not exceed 0.6 wt.-%, based on the overall weight of the inventive electrocoat material. Even more preferably, the amount (also called fraction) does not exceed 0.5 wt.-% or even does not exceed 0.4 wt.-%, in each case based on the overall weight of the electrocoat material.

[0133] However, a certain residual amount of such plasticizer, quite obviously, may be desired or even necessary in certain embodiments to provide for the corresponding plasticity of the electrocoat material. Therefore, preferably, in one embodiment it is preferred that the amount of ethoxylated bisphenol A, more particularly bisphenol A 6EO, is at least 0.1 wt.-%, based on the overall weight of the electrocoat material.

[0134] Therefore, in one particular embodiment, the electrocoat material comprises from 0.1 wt.-% to 0.6 wt.-%, more preferably from 0.1 wt.-% to 0.5 wt.-% and even more preferably from 0.1 wt.-% to 0.4 wt.-%, in each case based on the overall weight of the electrocoat material.

[0135] As a further example, also well-known plasticizers in electrocoat applications are polypropylene glycol variants, for example polypropylene glycol 900. While addition and increase of amounts of such plasticizers, respectively, may increase the surface energy by enrichment of the plasticizer at the surface region of a baked coating, it turned out that under overbake conditions these plasticizers may also have certain drawbacks, in particular in combination with high UV light exposure (overbaking and UV may lead to deterioration of the glycol chains, thus leading to surface defects and decreased quality). Therefore, in a preferred embodiment of the present invention, the amount of polypropylene glycol-based components, more particularly polypropylene glycol-based plasticizers, does not exceed 0.6 wt.-%, more preferably does not exceed 0.5 wt.-%, or does even not exceed 0.4 wt.-%, in each case based on the overall weight of the electrocoat material. 240661 WO01 - Secondary Filing Text - 28 -

[0136] BASF Coatings GmbH

[0137] In a preferred embodiment, the aqueous cathodically depositable electrodeposition coating material is characterized in that a baked electrodeposition coating layer produced from the material on a steel substrate (electric oven, 170°C substrate temperature, 15 minutes) has a surface energy of at least 55 mJ / m2Preferred ranges in surface energy are from 50 to 100 mJ / m2, more preferably from 55 to 75 mJ / m2

[0138] Preparation of the inventive electrodeposition coating material composition:

[0139] The electrodeposition coating material composition is preferably prepared by mixing and homogenizing a pigment paste (II) prepared by (i) grinding / milling the respective pigment / filler with the above-described components (d) and (e) and potentially further components / additives and solvents / water and (ii) mixing and homogenizing the pigment paste with the aqueous binder dispersion (I) (prepared by mixing and homogenizing the respective constituents, in particular components (a) and (b) and preferably also water). Mixing and homogenization can be performed by using customary and known mixing techniques and apparatuses such as stirred tanks, stirred mills, extruders, kneading apparatuses, Ultraturrax, inline dissolvers, static mixers, micromixers, toothed-gear dispersers, pressure relief nozzles and / or microfluidizers.

[0140] Serial cathodic electrodeposition coating process

[0141] At first, general aspects for understanding and specification of a cathodic electrodeposition coating process shall be described. Thereafter, details and particularities of the serial character shall be described. All described embodiments like preferred and specific embodiments described in the section of general aspects on a cathodic electrodeposition coating process are also embodiments of the inventive serial process.

[0142] According to a step i. of a cathodic electrodeposition coating process, an electrically conductive substrate (i.e. a to be coated metallic substrate) is immersed in an electrodeposition bath comprising an aqueous cathodic electrodeposition coating material. Thereby, the substrate (which is connected to a current circuit as cathode) is 240661 WO01 - Secondary Filing Text - 29 -

[0143] BASF Coatings GmbH contacted with the electrodeposition coating material composition described previously. The electrically conductive substrate preferably comprises a motor vehicle (automotive body) or part thereof. As outlined in the introductory part, one decisive advantage of the electrodeposition coating material composition and respective process is that both and concurrently in situations where parts of a coated substrate are exposed to overbake conditions and where other parts are exposed to baking conditions with comparably low temperature and thus energy, the overall performance of the formed baked coating layer is excellent. Therefore, substrates having a three- dimensional geometry and having different regions with varying substrate thicknesses are preferred. Three-dimensional geometry, in the here discussed sense, quite obviously means that the substrate is not a simply flat substrate like a flat metal sheet. More particularly, automotive bodies are preferred substrates.

[0144] The application (or depositing) of the electrodeposition coating material composition to the substrate, or the production of a coating film on the substrate, according to a step ii. of the process are understood as follows: The composition (material) is applied in such a way that the coating film / layer produced therefrom is arranged on the substrate but need not necessarily be in direct contact with the substrate. Thus, other layers can be present between the coating film and the substrate. For example, a conversion coating, such as a zinc phosphate coating, may be arranged between the substrate and the cured electrocoating layer.

[0145] The method (or process) is preferably a method for at least partly coating an electrically conductive substrate used in and / or for automobile construction.

[0146] Within step ii. of a cathodic electrodeposition coating process, the substrate is at least partly coated with the aqueous electrocoating material by cataphoretic deposition of this coating material on the substrate surface. This is accomplished by introducing the substrate at least partly, preferably completely, into a dip-coating bath containing the electrocoating material (cf. step i.) and applying an electrical voltage between the substrate (as cathode) and at least one counterelectrode. The counterelectrode may in this case be located in the dip-coating bath. Alternatively or additionally, the 240661 WO01 - Secondary Filing Text - 30 - BASF Coatings GmbH counterelectrode may also be present separately from the dip-coating bath, for example via an anion exchange membrane which is permeable to anions. In this case, anions formed during dip coating are transported from the coating material through the membrane into the anolyte, allowing the pH in the dip-coating bath to be regulated or kept constant. The counterelectrode is preferably separate from the dip-coating bath. The passage of electrical current between anode and cathode is accompanied by deposition of a firmly adhering paint film on the cathode, i.e. , on the substrate. Overall, it can be said that the deposition process includes connecting the substrates as cathode of a circuit and applying an electric voltage.

[0147] This step ii. of a cathodic electrodeposition coating process is carried out preferably at a temperature in a range from 25 to 35°C and a voltage of 120 to 350 V, preferably of 150 to 320 V. The voltage may be kept constant during the stated duration. Alternatively, however, the voltage may also adopt different values during the deposition duration within the minimum and maximum previously listed - for example, it may swing back and forth or rise in ramp or step form from the minimum to the maximum deposition voltage. In such a step ii. of the method, preferably, there is full coating of the substrate with the aqueous electrocoating material, by complete cataphoretic, deposition on the entire substrate surface.

[0148] In a step ii. of a cathodic electrodeposition coating process, the aqueous electrocoating material (ECM) is preferably applied such that the resulting cured electrocoat film has a dry film thickness in the range from 5 to 40 pm, more preferably from 10 to 30 pm, especially preferably from 20 to 25 pm.

[0149] Thereafter, the coated substrate is removed from the electrodeposition bath (step iii.).

[0150] In an optional step, the at least partially coated substrate is rinsed with water. The implementation of this optional step permits the recycling of excess constituents of the aqueous electrocoating material, present after step iii. on the at least partly coated substrate, into the dip-coating bath. 240661 WO01 - Secondary Filing Text - 31 -

[0151] BASF Coatings GmbH

[0152] In a step iv. of a cathodic electrodeposition coating process, the coating layer obtained from at least partially applying the aqueous electrocoating material on the substrate is cured (baked).

[0153] Curing of a the electrocoating film is understood to mean the conversion of such a film to the ready-to-use state, i.e. to a state in which the substrate provided with the respective coating film can be transported, stored and used as intended. More particularly, a cured coating film is no longer soft or tacky, but has been conditioned as a solid coating film which does not undergo any further significant improvement in its desired properties, such as hardness or adhesion on the substrate, even under further exposure to curing conditions.

[0154] Such a step iv. of a cathodic electrodeposition coating process is carried out preferably by means of baking after the previous steps, preferably in an oven. The curing here takes place preferably at an oven temperature in the range from 150 to 250 °C, preferably 160 to 230°C (oven temperature means the adjusted oven temperature and thus the ambient temperature within the oven) for a duration of, for example, 10 to 120 minutes like 30 to 90 minutes. Further essential details of the curing step iv. are outlined below.

[0155] After having performed such step iv., an electrocoat layer (or film) results.

[0156] Also, after having preformed step vi. and thus having produced an electrocoat layer, one or more further coating layers can be applied onto the baked electrodeposition coating film obtained after step vi.. For example, a primer and / or filler can be applied and cured, followed by a basecoat and a clearcoat which are then jointly cured. Also, it is possible to directly apply a basecoat or more than one (for example two) basecoat layers onto the electrocoat layer followed by applying at least one clearcoat layer on top of the basecoat layer (the upmost basecoat layer), whereby all of these applied layers are then jointly cured (so called integrated processes). Thereby, a (likewise inventive) multilayered coating assembly (for example an automotive multilayered coating assembly) is produced. 240661 WO01 - Secondary Filing Text - 32 -

[0157] BASF Coatings GmbH

[0158] In the following, details and characteristics on a serial process are outlined (even if anyway known to the person skilled in the art). A serial process means that a plurality of substrates (i.e. for example at least 10 substrates or at least 50 substrates or even at least 100 substrates) are consecutively treated according to the respective features of the process, i.e. immersing, depositing / coating, removing and baking. The term “consecutively”, in particular, means that the respective steps start (and end) consecutively for the regarded substrates, i.e. an immersing of a first substrate starts before an immersing of a second substrate or the depositing on the first substrate starts before the depositing on the second substrate. Of course, however, it regularly happens that more than one substrate concurrently is subject to a certain step, for example the deposition and / or curing process. Reason is that industrial coating lines regularly have capacities I spaces being aligned in a way that multiple consecutive substrates concurrently fit into the respective area of, for example, deposition (i.e. the deposition bath) or curing (i.e. the oven). As, in such coating lines, the substrates are normally successively passed through the coating line with a certain and adjusted velocity, it most often happens that more than one substrate is concurrently treated as outlined above. However, due to the successive passing-through principle, the start (and end) or the respective process step deviates I lie one after another.

[0159] In the following, details and characteristics on the curing step vi. are outlined. As already outlined in the introductory part, in serial process within an industrial coating line, substrate regions with higher and lower temperature / energy exposure will result. In an oven, a preset oven temperature together with a preset residence time of the substrate within the oven (steered, for example, by the velocity of the passing-through in the coating line) will influence the overall temperature and energy exposure of the substrate. More importantly, however, different regions of the substrate will be exposed to different conditions in this regard. In other words: Such adjusted (preset) oven temperature in combination with a preset residence time of the substrate, in particular substrate with three-dimensional geometry and having different regions with varying substrate thicknesses, normally means that the substrate temperature and thus temperature to which a deposited electrocoat material is exposed to, will vary for each single substrate in a way that different parts of the substrates are exposed to a different 240661 WO01 - Secondary Filing Text - 33 -

[0160] BASF Coatings GmbH temperature. Interestingly, the prior art does not lie any focus on this aspect, nor on any issues connected to this aspect. Even less, any measures to encounter these issues are disclosed.

[0161] As the substrate, within the oven, also needs to be heated and such heating will require a certain time depending on region and thickness of the substrate, the duration for which a substrate is heated to a certain temperature or temperature range will vary. Therefore, the overall energy (temperature and time) to which different parts of the substrate and thus deposited coating material is exposed correspondingly varies.

[0162] Step vi. is conducted in a way that parts (i) of individual metallic substrates and corresponding parts of the coating material deposited on individual metallic substrates are heated to a temperature of above 200°C for a duration of at least 10 minutes and other parts (ii) of the same individual metallic substrates and thus corresponding other parts of the coating material deposited on individual metallic substrates are heated to a temperature between 160 and 190°C (preferably between 160 and 190°C) for a duration of at least 10 minutes, whereby these parts (ii) are not heated to a temperature of above 190°C (preferably not above 180°C) during the entire step iv. and thus, preferably, during the entire method of the invention. To be clear, the above-specified temperatures refer to the substrate (and deposited electrocoat material, respectively).

[0163] Quite obviously, the above does not exclude that parts (i) and / or parts (ii) are heated - intermediately - to a temperature below the above-defined ranges. In fact, within an oven as described above, this would be the standard (as the substrate and thus parts (i) and (ii) are gradually heated and thus run through a temperature profile making it necessary that such lower temperatures are realized. The same principle is true for the subsequent cooling process).

[0164] Also quite obviously, the above does not exclude that further parts (iii) of the individual substrate are heated to other temperatures. However, preferably, no part of the substrate is heated to a temperature of above 240°C, more preferably above 220°C for the entire step iv. and thus during the entire method of the invention. 240661 WO01 - Secondary Filing Text - 34 - BASF Coatings GmbH

[0165] Step iv. preferably is conducted in standard industrial ovens as known by the person skilled in the art, i.e. electric ovens and / or gas ovens. As is known, gas ovens (which are often used in situations where the purchase price of gas is comparably low) create an aggressive oxidative atmosphere by creation of nitrogen oxides (NOx) within the combustion process. This, in turn, may have negative reactive impact on the coating surface, ultimately leading to a lowering in surface energy and decreased UV stability. Within electric ovens, such negative influence, quite obviously, is not existing.

[0166] It is a particular advantage of the present invention that both under curing in electric ovens as well as in gas ovens an optimal UV stability for ultimately produced multilayer coating assemblies is gained.

[0167] Coated substrate and component or article comprising the coated substrate

[0168] A further subject of the present invention is an at least partly coated electrically conductive substrate which is obtainable by means of the method of the invention.

[0169] A further subject of the present invention is a preferably metallic component or preferably metallic article each produced from at least one such substrate.

[0170] Such articles may be, for example, metal strips. Components of this kind may also however - and preferably in the context of the present invention - be bodies and bodywork parts of vehicles such as automobiles, trucks, motorcycles, buses, and coaches, and components of electrical household products, or else components from the area of apparatus claddings, fagade claddings, ceiling claddings, or window profiles. As mentioned above, more particularly, automotive bodies are preferred substrates. 240661 WO01 - Secondary Filing Text - 35 - BASF Coatings GmbH

[0171] Examples

[0172] The present invention will now be explained in greater detail through the use of working examples, but the present invention is in no way limited to these working examples. Moreover, the terms "parts", "%" and "ratio" in the examples denote "parts by mass", "mass %" and "mass ratio" respectively unless otherwise indicated.

[0173] 1. Methods of determination:

[0174] 1.1 Solids content (solids, nonvolatile fraction)

[0175] The nonvolatile fraction is determined according to DIN EN ISO 3251 (date: June 2008). It involves weighing out 1 g of sample into an aluminum dish which has been dried beforehand, drying it in a drying oven at 130°C for 60 minutes, cooling it in a desiccator and then reweighing it. The residue relative to the total amount of sample used corresponds to the nonvolatile fraction.

[0176] 1 .2 Determination of glass transition temperature Tg

[0177] The glass transition temperature Tgis determined with differential scanning calorimetry (DSC) according to DIN 53765:1994-03 using a heating rate of 10 K / min.

[0178] 1.3 Determination of crosslinking start temperature and duration of crosslinking with DMA

[0179] The crosslinking start temperature of the deposited electrocoating materials and the duration of the crosslinking is determined experimentally by means of dynamic mechanical thermal analysis (DMTA). In the DMTA, by applying an oscillating force to the sample, the mechanical properties are determined guantitatively depending on the temperature, time and freguency. Most samples are elastic (stiff) and viscous (dampening) at the same time, i.e. they are viscoelastic. Thus, an applied load is partly released by viscous flow with a permanent deformation. At the same time, the mechanical behavior depends on temperature, time, height and type of the applied load. Instead of using a free coating film a small amount of the material to be examined is applied on a piece of a carbon fiber net which is clamped in the device. 240661 WO01 - Secondary Filing Text - 36 - BASF Coatings GmbH

[0180] The measurements were made with a Triton 2000B type instrument from Triton Technology according to the procedure described in patent application DE 4 409 715 A1 . However, a carbon fiber net is used instead of a glass fiber net. The measurement takes place in a temperature range relevant to the sample (here: from 2 °C to 200 °C).

[0181] Depending on the temperature control, two types of measurement are possible:

[0182] Start of crosslinking - onset measurement:

[0183] Throughout the measurement, the measured tan 6 and E' values are affected by the properties of the carbon fiber network, so the values should not be used as absolute values. As soon as the crosslinking of the electrocoating material begins, however, these values change drastically. The temperature at which this change begins marks the onset of crosslinking and is determined graphically from the memory module / temperature diagram. It is the temperature of the intersection of the extrapolated baseline of the memory module prior to onset crosslinking and the extrapolated straight line resulting from the quasi-linear ramp up region of the memory module after onset of crosslinking. In this way, the crosslinking start temperature can be accurately determined to + / - 2 ° C.

[0184] Crosslinking duration - offset measurement:

[0185] The temperature during the measurement is changed according to the line condition characteristic of the deposited electrocoating material (furnace curve). As soon as the crosslinking of the deposited material starts, E' increases and then assumes a constant value after completion of the crosslinking. Throughout the measurement, the measured E' values are affected by the properties of the carbon fiber network, so the values should not be used as absolute values. With this measurement, the offset time, i.e. the time necessary for sufficient crosslinking at a given temperature mode, can be determined.

[0186] 1 .4 Determination of pH value

[0187] The pH value was determined according to DIN 55659-1 (Jan 2012). 240661 WO01 - Secondary Filing Text - 37 - BASF Coatings GmbH

[0188] 1 .5 Determination of

[0189] The conductivity was determined according to DIN EN ISO 15091 (April 2013).

[0190] 1 .6 Determination of epoxy equivalent weiqht

[0191] The epoxy equivalent weight is determined according to DIN EN ISO 3001 :1999-11.

[0192] 1 .7 Determination of surface energy of baked electrodeposition coating layer (electric oven, 170°C substrate temperature, 15 minutes)

[0193] The surface energy of the samples (prepared according to chapter 3.2 below, electric oven, 170°C substrate temperature, 15 minutes) is measured by determination of the contact angle according to ISO19403-2. The samples are stored for 16 h at 23 °C and ca. 50 % relative humidity. At least six droplets for each of 3 different testing liquids (water, diiodomethane, ethylene glycol) are set onto the sample and the contact angle is analyzed. The average value from the at least six droplets is determined for each of the testing liquids. With these average values of the contact angles the polar and disperse amount of the surface energy is calculated by the method of Owens, Wendt, Rabel and Kaelble.

[0194] 1 .8 Determination of corrosions resistance

[0195] VDA climate change test (DIN EN ISO 11997-1 : 2018-01 ). This climate change test is used to determine the corrosion resistance of a coating on a substrate. The climate change test is carried out in 5 or 10 so-called cycles. If the coating of the samples to be tested is scored down to the substrate with a knife cut before the climate change test is performed, the samples can be tested for their degree of under-film corrosion in accordance with DIN EN ISO 4628-8 (03-2013), since the substrate corrodes along the scoring line during the climate change test. As corrosion progresses, the coating is more or less infiltrated during the test. The degree of undermining in [mm] is a measure of the corrosion resistance of the coating. 240661 WO01 - Secondary Filing Text - 38 - BASF Coatings GmbH

[0196] 2. Preparation of aqueous cathodic electrodeposition coatinq materials

[0197] The following should be taken into account regarding the formulation constituents and amounts thereof as indicated in the tables hereinafter. When reference is made to a commercial product or to a preparation protocol described elsewhere, the reference, independently of the principal designation selected for the constituent in question, is precisely this commercial product or precisely the product prepared with the referenced protocol.

[0198] 2.1 Preparation of epoxy-based polymer (e)

[0199] An aqueous dispersion of a polymer (e) is prepared by using the amounts of components 1 to 9 stated in Table 1 below as follows:

[0200] Components 1 to 3 are loaded into a reactor and heated to 125 °C. Afterwards, the catalyst 4 is added in two portions and the reaction is continued at 125 °C until the epoxy equivalent weight is determined to be 271 g / mol to ensure complete conversion of component 3. The reactor is cooled to 50 to 90 °C and component 5 is added. Afterwards, component 6 is added and an exothermic reaction of the amine with the epoxy groups is observed. After addition of component 7, the reactor is held at 110 °C for 2 to 3 hours until complete conversion of the epoxy groups is achieved (corresponds to an epoxy equivalent weight of > 40.000g / mol). The respective resin is dispersed in a mixture of components 8 and 9 to obtain the dispersion of polymer (e).

[0201] 240661 WO01 - Secondary Filing Text - 39 -

[0202] BASF Coatings GmbH

[0203] Table 1 : Components used in the preparation of dispersion of polymer (e) (all amounts are given in %by weight, based on the total weight of the respective grind resin dispersion)

[0204] 1)high viscosity liquid epoxy resin based on Bisphenol A diglycidyl ether, epoxy equivalent = 188 g / mol (= g / Eq.) (determined according to ISO3001 ), viscosity at 25 °C = 12,000 to 14,000 mPa*s (determined according to ISO 12058-1 , falling ball) (supplied by Huntsman)

[0205] 2)Polypropylenglycol diglycidyl ether, epoxy equivalent = 395 mol / g (determined according to ISO3001 ), viscosity at 25 °C = 42 to 52 mPa*s (determined according to ISO 12058-1 , falling ball) (supplied by Huntsman)

[0206] 3)4-docecyl phenol

[0207] 4)R1to R3= hydrogen, a = 2, b = 1

[0208] 5)3-(dimethylamino)-1 -propylamine

[0209] The dispersion of polymer (e) has a solids content of 35 % (see point 1.1 above), a viscosity of about 150 to 230 m*Pas (see point 1.9 above) and a theoretically calculated base equivalent of 1 .64 meq / g of solid resin. The molar ratio of compound (e2) of formula (I) with R1to R3= hydrogen, a = 2, b = 1 to epoxy compounds (e1 -1 ) and (e1 -2) in polymer (e) is 1 : 1 .49. The molar amount, quite obviously, was calculated by using the total molar amount of the epoxy compounds (e1 -1 ) and (e1 -2) as well as compound (e2) used to prepare the polymer.

[0210] 2.2. Preparation of pigment pastes

[0211] The pigment paste PP is prepared according to the procedure described in European Patent EP 0 505 455 B1 on page 10, lines 35 to 42 using the starting materials listed in Table 2 below. For this purpose, deionized water and polymer (e) as prepared above are premixed. Then the remaining ingredients according to the amounts stated in Table 2 are added and the obtained mixture is stirred for 30 minutes in a high-speed dissolver stirrer. Subsequently, the mixture is dispersed in a small laboratory mill for 1 to 1.5 240661 WO01 - Secondary Filing Text - 40 - BASF Coatings GmbH hours to a Hegmann fineness of less than 12. During or after the grinding, the viscosity is adjusted to 1 ,400 ± 400 mPa*s (determined with a rotational viscosimeter Rheolab QC (Paar Instruments) using a CC39 measuring system at a temperature of 25 °C and a shear rate of 10 s-1) with water.

[0212] Table 2: Components used in the preparation of pigment paste PP (all amounts are given in %by weight, based on the total weight of the pigment paste)

[0213] Also, a pigment paste P1 was prepared. This pigment paste P1 equals pigment paste P1 in accordance with WO2021 / 239264A1 , page 37, lines 1 -26, in particular Table 2.

[0214] The amount of bismuth (calculated as metal) in pigment paste PP is 1 .46 wt.-%, while for pigment paste P1 the amount is 4.38 wt.-%.

[0215] 2.3. Preparation of aqueous cathodic electrodeposition coating materials (as baths) Pigment paste P1 described above is combined in accordance with Table 3 below. The procedure here is to introduce the aqueous binder dispersion (I) as an initial charge and to dilute it with deionized water. Subsequently, with stirring, the pigment paste is introduced. The aqueous cathodic electrodeposition coating materials or aqueous electrocoating materials are abbreviated as “ECM”. 240661 WO01 - Secondary Filing Text - 41 -

[0216] BASF Coatings GmbH

[0217] Table 3: Components used in the preparation of aqueous electrocoating materials (all amounts are given in % by weight, based on the total weight of the electrocoating material)

[0218] * for inventive use

[0219] 1)Aqueous binder dispersion containing cathodically depositable polymer (a) and crosslinking agent (b) and further customary components like additives and organic solvents. (BD1 ) contains an amount of 1 .57 wt.-% of bisphenol A 6EO.

[0220] 2)Adaption of aqueous binder dispersion (BD1 ). (BD2) contains an amount of 0.81 wt.- % of bisphenol A 6EO (while the amounts of further components were slightly adapted (i.e. increased) to add up for 100 %).

[0221] 3)Aqueous binder dispersion (BD) according to WO2021 / 239264A1 , page 38, Table 3.

[0222] ECM-1 contains an amount of 0.66 wt.-% of bisphenol A 6EO as plasticizer, while ECM-3 und ECM-4 contain 0.33 wt.-% of this plasticizer. ECM-2 does not contain bisphenol A 6EO as plasticizer, but polypropylene glycol 900 (plasticizer) in an amount of 0.66 wt.-%. Accordingly, all electrocoat materials ECM-1 , ECM-3 and ECM-4 do not contain any polypropylene glycol-based plasticizer.

[0223] 3. Characteristics of the aqueous electrocoatinq materials (ECMs)

[0224] The pH value, the conductivity at 20 °C, the solid content and the surface energy (electric oven, 170°C, 15 min) were determined according to the above-mentioned methods. The obtained values are listed in Table 4 below. Table 4 also lists the amount of bismuth (calculated as metal). 240661 WO01 - Secondary Filing Text - 42 -

[0225] BASF Coatings GmbH

[0226] Table 4: Characteristic parameters of electrocoating materials ECM-1 to ECM-4

[0227] * for inventive use

[0228] As can be observed from Table 4, the bismuth content of ECM-3 (for inventive use) is lower than for the residual electrocoat materials.

[0229] 3.2 Deposition on electrically conductive substrates

[0230] The electrocoating materials ECM-1 to ECM-4 are aged at room temperature with stirring for 24 h, respectively. The electrocoat materials are then deposited on zinc- phosphatized steel panels (Gardobond GB26S 6800 OC, supplied by Chemetall) connected as cathodes. The deposition time is 120 s at a bath temperature of 32° C and a deposition voltage of 240 to 320 V (ultimately resulting in a dry film thickness of 15 to 25 Micrometer).

[0231] The deposited coating films are rinsed with deionized water and baked in different ovens for 15 minutes at different substrate temperatures. Specifically, a first set of coated substrates were cured at 170°C substrate temperature for 15 min (electric oven and gas oven), while a second set of coated substrates were cured at 210°C substrate temperature for 15 min (electric oven and gas oven). Quite obviously, the substrate first needs to be heated up to the above specified substrate temperature after being introduced into the oven, before then being held at this temperature for the specified duration of 15 minutes. While it is not particularly important how long this heating process takes (and, specifically, no influence on the surface energy according to chapter 1 .7 is noticed), the oven size I oven power and substrate size I substrate weight may be adapted in a way that the heating takes between 5 to 20 minutes, for example 10 minutes. Also, the substrate temperature as such, quite obviously, is a direct measure of the temperature of the deposited electrocoating material (as the thin layer of coating material will have a temperature adapted to that of the substrate). 240661 WO01 - Secondary Filing Text - 43 -

[0232] BASF Coatings GmbH

[0233] By the above procedure, the situation of a complex three-dimensional substrate geometry (like an automotive body) and corresponding deviations in heat / energy exposure during baking / curing of different parts of such substrates is validly modelled. In particular, the above procedure is a valid representation of the specific substrate temperature I duration of stay profile with regard to parts (i) and parts (ii) of individual metallic substrates as defined in the context of the technical solution of the present invention.

[0234] Also, for different types of ovens, both being in use in industrial scale electrodeposition processes, the above procedure is a valid representation.

[0235] 3.3 Determination LIV stability and general electrocoat layer properties

[0236] The baked E-Coat panels were coated with a standard multilayer topcoat system (produced by means of two aqueous basecoats and one clearcoat, i.e. by successive application of the three coating compositions and then joined curing). Afterwards, the multicoated panels were analyzed according to their UV stability (cross cutting, UV light exposure). A high UV stability corresponds to a low blistering I delamination of the topcoat system.

[0237] All multicoated panels prepared by ECM curing at 170°C substrate temperature (electric oven and gas oven) showed a decent UV stability. However, from multicoated panels prepared by ECM curing at 210°C substrate temperature (electric oven and gas oven), only those produced via the inventive electrocoat materials ECM-3 showed significant superior UV stability compared to the residual samples. While the panel based on ECM-4 showed a better performance that the panels based on ECM-1 und ECM-2 (which showed significant delamination), only the ECM-3 based system showed an optimal UV stability behavior. Furthermore, the coating film quality of the ECM-3 system was significantly better than of the ECM-4 system. 240661 WO01 - Secondary Filing Text - 44 -

[0238] BASF Coatings GmbH

[0239] Furthermore, all baked panels (ECM-1 to ECM-4, 170°C I 210°C substrate temperature, electric oven, gas oven) showed appropriate and comparable properties on glass transition temperature (method 1 .2 above), crosslinking behavior (method 1 .3 above) and corrosion resistance (method 1.8 above).

Claims

240661 WO01 - Secondary Filing Text - 45 - BASF Coatings GmbHClaims1. A serial cathodic electrodeposition coating process for metallic substrates comprising i. immersing to be coated metallic substrates in an electrodeposition bath comprising an aqueous cathodic electrodeposition coating material, ii. depositing cathodic electrodeposition coating material on the metallic substrates, whereby the deposition process includes connecting the substrates as cathode of a circuit and applying an electric voltage, iii. removing the coated substrates from the electrodeposition bath, and iv. baking the coating material deposited on the metallic substrates, wherein- the aqueous cathodic electrodeposition coating material comprises at least one aqueous binder dispersion (I) comprising (a) at least one cathodically depositable polymer having functional groups (a1 ) and (b) at least one crosslinking agent having functional groups (b1 ) being complementary to the functional groups (a1 ), meaning that functional groups (a1 ) and (b1 ) are capable to undergo crosslinking reactions, and a pigment paste (II) comprising at least one filler and / or pigment (c), at least one bismuth compound (d) and at least one epoxy-based polymer (e) being different from polymer (a), wherein the epoxy-based polymer (e) comprises at least one epoxy- group containing compound (e1 ) and at least one amine-group containing compound (e2),- the amount of bismuth (calculated as metal), based on the total amount of the aqueous cathodically depositable electrodeposition coating material, is at most 0.15 wt.-%, and- the baking step iv. involves that parts (i) of individual metallic substrates and corresponding parts of the coating material deposited on individual metallic substrates are heated to a temperature of above 200°C for a duration of at least 10 minutes and other parts (ii) of the same individual metallic substrates and thus corresponding other parts of the coating material deposited on individual metallic substrates are heated to a temperature between 160 and 190°C for a duration of at least 10 minutes, whereby the parts (ii) are not heated to a temperature of above 190°C during the entire step iv.240661 WO01 - Secondary Filing Text - 46 - BASF Coatings GmbH2. Serial process according to claim 1 , wherein the compound (e2) contains both an amine-group and a hydroxy group.

3. Serial process according to claim 1 or 2, wherein the fraction of compound (e2) is at least 5 wt.-%, preferably at least 6.5 wt.-%, in each case based on the overall weight of the epoxy-based polymer (e).

4. Serial process according to any of claims 1 -3, wherein a baked electrodeposition coating layer produced from the aqueous cathodic electrodeposition coating material on a steel substrate (electric oven, 170°C substrate temperature, 15 minutes) has a surface energy of at least 50 m J / m25. Serial process according to any of claims 1 -4, wherein the amount of polypropylene glycol-based plasticizers in the aqueous cathodic electrodeposition coating material does not exceed 0.6 wt.-%, based on the overall weight of the electrodeposition material.

6. Serial process according to any of claims 1 -5, wherein the baking step iv. involves that parts (i) of individual metallic substrates and corresponding parts of the coating material deposited on individual metallic substrates are heated to a temperature of above 200°C for a duration of at least 10 minutes and other parts (ii) of the same individual metallic substrates and thus corresponding other parts of the coating material deposited on individual metallic substrates are heated to a temperature between 160 and 180°C for a duration of at least 10 minutes, whereby the parts (ii) are not heated to a temperature of above 180°C during the entire step iv.

7. Serial process according to any of claims 1 -6, wherein within the process at least 10 individual substrates are consecutively processed.

8. Serial process according to any of claims 1 -7, wherein within the process at least 100 individual substrates are consecutively processed.240661 WO01 - Secondary Filing Text - 47 -BASF Coatings GmbH9. Serial process according to claim 7 or 8, wherein the process is conducted in an industrial coating line and wherein the substrates are successively passed through the coating line with a certain and adjusted velocity.

10. Method according to any of claims 1 -9, wherein the substrates have three- dimensional geometry (i.e. not flat substrates like a flat metal sheets) with varying thicknesses (i.e. at least some different parts of the substrates have varying thicknesses).

11. Method according to any of claims 1 -10, wherein the substrates are automotive bodies.

12. Coated substrates produced according to the method of any of claims 1 -11.

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