Electrodeposition coating composition containing alkoxylated polyethyleneimine

Abstract

The present invention relates to an aqueous cathodic electrodeposition coating composition comprising at least one binder dispersion (I) containing at least one cathode-depositable polymer (a) and at least one pigment paste (II) containing at least one pigment and / or filler. The production of the electrodeposition coating composition includes mixing the binder dispersion (I) and the pigment paste (II). The composition also contains at least one alkoxylated polyethyleneimine (b), and at least one alkoxylated polyethyleneimine (b) is part of at least one binder dispersion (I) and / or part of at least one pigment paste (II).

Description

Technical Field

[0001] The present invention relates to an aqueous cathodic electrodeposition coating composition comprising at least one binder dispersion (I) containing at least one cathodic depositing polymer (a) and at least one pigment paste (II) containing at least one pigment and / or filler, wherein the dispersion (I) and / or the paste (II) contains at least one alkoxylated polyethyleneimine (b). The present invention also relates to a kit of parts for producing an aqueous cathodic electrodeposition coating composition and a method for producing such a composition. The present invention also relates to a method for at least partially coating a conductive substrate, the method comprising at least step (1) of at least partially immersing the substrate in an electrodeposition coating bath containing the electrodeposition coating composition of the present invention, and being by cathodic electrodeposition coating comprising at least steps (1) to (5). The present invention further relates to a conductive substrate at least partially coated with the baked electrodeposition coating composition of the present invention and / or obtainable by the method of the present invention.

[0002] In the automotive field, metal parts used in manufacturing usually need to be protected from corrosion. The requirements regarding corrosion inhibition to be achieved are extremely strict. This is all the more so since manufacturers often guarantee that there will be no rust perforation over the years. Such corrosion inhibition is usually achieved by applying a coating film with at least one coating suitable for the purpose to the components or to the substrates used in the manufacture of the components.

[0003] To ensure the necessary corrosion inhibition, it is a common method to apply an electrodeposited coating film to its metal substrate. At this time, the substrate may be pretreated by phosphate treatment and / or other types of pretreatment. Electrodeposition (electrocoat) paints are paints that contain a polymer as a binder and optionally a crosslinking agent, pigments and / or fillers, and often additives. Generally, there are anodic deposition electrocoat materials and cathodic deposition electrocoat materials. In particular, an anodic electrodeposition coating composition containing metallic effect pigments is disclosed, for example, in WO2006 / 117189A1. However, cathodic deposition materials are the most important in industrial painting, especially in automotive finishing. In cathodic electrodeposition coating, the substrate to be coated is immersed in an electrocoat bath and connected as the cathode. The bath has an anode as the counter electrode. The particles of the electrocoat material are stabilized with a positive charge and deposit on the cathode to form a coating film. After deposition, the coated substrate is removed from the electrocoat bath, rinsed with water, and then the coating film is baked, that is, thermoset.

[0004] Cathodic deposition electrocoat materials are known in the prior art, for example, in EP1041125A1, DE19703869A1, and WO91 / 09917A2.

[0005] As already mentioned, the main purpose of the cathodic deposition electrocoat material is to protect metal substrates from corrosion. In the automotive field, these substrates are typically metal components such as automotive body panels and lateral control arms, spring-loaded control arms, or dampers. These substrates inherently include multiple edges due to their shape and processes such as stamping that occur prior to the painting process. These edges remain a major challenge for proper corrosion protection during the electrocoating process. While protection of surfaces and flats is fairly well established, current optimal technical solutions for edges have not been achieved. The reason, although quite obvious, is that even considering the particularities and advantages of electrocoating, it is difficult to build a sufficient film on the edges by changing the viscosity during softening of the film during curing while ensuring sufficient material flow to achieve the desired leveling of the film on the surfaces and flats. This effect is even more important and relevant because, for economic reasons, in recent industrial painting processes, sharp edges often remain unrounded and unchanged in post-treatment processes such as sanding and polishing processes of substrate edges are often omitted, making painting even more difficult. As a result, the thickness of the paint film becomes thinner, and the corrosion protection of these edges decreases.

[0006] One way to address this problem is to increase the viscosity of the deposited electrocoat material and further promote the increase in viscosity during curing. However, this often simultaneously results in an increase in the surface roughness of the coating because the material cannot be leveled evenly after application and during curing. However, an increase in surface roughness is an effect to be avoided in the automotive painting industry because its correction requires severe effort or is completely impossible during the formation of subsequent coating layers, making the resulting aesthetic properties of automotive multi-layer coatings unacceptable. In fact, avoidance of high surface roughness is one of the major challenges in electrocoating in the automotive industry while achieving good corrosion protection.

[0007] Therefore, there is a need to provide an electrocoating paint that can enhance the corrosion protection of the edges of metal substrates without adversely affecting the surface roughness of the electrocoated substrates.

[0008] US2010 / 0143632A1 describes a composition containing a mixture of polyethyleneimine and poly(meth)acrylic acid for obtaining corrosion protection of a metal substrate. Edge corrosion is not described. Also, nothing is disclosed about an electrocoat composition, let alone a cathodic depositable electrocoat composition. This is consistent with the finding (shown below in the Examples section) that such polyethyleneimine does not perform in a cathodic depositable electrocoat composition, i.e., such a cathodic depositable electrocoat composition is not depositable.

Prior Art Documents

Patent Documents

[0009]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Summary of the Invention

Problems to be Solved by the Invention

[0010] Accordingly, an object of the present invention is to provide an electrocoat that can build a smooth and homogeneous film when applied onto a metal substrate, whereby the resulting coating exhibits excellent corrosion resistance in the edge regions.

[0011] This object is solved by the subject matter of the claims of the present application and its preferred embodiments disclosed herein, i.e., by the subject matter described herein.

Means for Solving the Problems

[0012] The first subject of the present invention is, (I) at least one binder dispersion containing at least one cathodic depositing polymer (a), and (II) at least one pigment paste containing at least one pigment and / or filler, an aqueous cathodic depositing electrocoating composition comprising: the production of the electrocoating composition comprising mixing the binder dispersion (I) and the pigment paste (II), the composition also containing at least one alkoxylated polyethyleneimine (b), and at least one alkoxylated polyethyleneimine (b) being part of the at least one binder dispersion (I) and / or part of the at least one pigment paste (II).

[0013] A further subject of the present invention is the following: (I) at least one binder dispersion containing at least one cathodic depositing polymer (a), and (II) at least one pigment paste containing at least one pigment and / or filler a kit of parts for producing an aqueous cathodic depositing electrocoating composition comprising: at least one alkoxylated polyethyleneimine (b) being part of the at least one binder dispersion (I) and / or part of the at least one pigment paste (II).

[0014] Also, the subject of the present invention is the following steps: - providing at least one binder dispersion (I) containing at least one cathodic depositing polymer (a), - providing at least one pigment paste (II) containing at least one pigment and / or filler, wherein the binder dispersion (I) and / or the pigment paste (II) contains at least one alkoxylated polyethyleneimine (b). - A step of mixing the binder dispersion (I), the pigment paste (II), and any further potential components of the composition A method for producing a cathodic electrodepositable coating composition, comprising:

[0015] A further subject of the present invention is a method for at least partially coating a conductive substrate by cathodic electrodeposition, comprising at least steps (1) to (5), namely: (1) A step of at least partially immersing a conductive substrate in an electrodeposition coating bath containing the electrodeposition coating composition of the present invention; (2) A step of connecting the substrate as a cathode; (3) A step of depositing a coating film obtained from the electrodeposition coating composition on the substrate using a direct current; (4) A step of removing the coated substrate from the electrodeposition coating bath; and (5) A step of baking the coating film deposited on the substrate. A method comprising the above steps.

[0016] A further subject of the present invention is a conductive substrate at least partially coated with the baked electrodeposition coating composition of the present invention and / or obtainable by the method of the present invention.

[0017] Surprisingly, it has been found that the electrodeposition coating composition of the present invention enables excellent edge corrosion protection of a conductive (i.e., metal) substrate. Furthermore, surprisingly, in addition to improved edge corrosion protection, it has been found that the homogeneity of the surface film remains of high quality, i.e., surface roughness is avoided. That is, the present invention thus achieves both two important properties of electrodeposition coating, namely high edge corrosion protection and excellent film homogeneity.

Embodiments for Carrying Out the Invention

[0018] The term "comprising" in the context of the present invention, for example in relation to the electrodeposition coating composition of the present invention, includes, but is not limited to, the meaning of "consisting of". Thus, for example, with respect to the electrodeposition coating composition of the present invention, in addition to components (a), (b) and water, one or more additional components specified below and optionally comprised in the electrodeposition coating composition of the present invention may be comprised in the composition. All constituents are present in their preferred embodiments as specified below in each case. "Consisting of" is also referred to as "comprising only" or "exclusively comprising", i.e., "comprising" is a generic term that includes the specific term "consisting of".

[0019] The electrodeposition coating composition of the present invention The cathodic electrodeposition aqueous coating composition of the present invention (hereinafter also referred to as the electrodeposition coating composition of the present invention or the composition of the present invention) comprises at least one binder dispersion (I) comprising at least one cathodic electrodepositable polymer (a) (also referred to as component (a)) and at least one pigment paste (II) comprising at least one pigment and / or filler. At least one, preferably exactly one, of components (I) and (II) comprises at least one alkoxylated polyethyleneimine (b) (also referred to as component (b)). Preferably, the composition of the present invention comprises exactly one alkoxylated polyethyleneimine (b). The terms "electrodeposition coating composition" and "electrodeposition painting composition" are interchangeable in the use herein.

[0020] The cathodic electrodeposition aqueous coating composition of the present invention is suitable for at least partially coating a conductive substrate with an electrodeposition coating composition, i.e., it means that the cathodic electrodeposition aqueous coating composition of the present invention is suitable for at least partially applying to the substrate surface of a conductive substrate, and by such application, an electrodeposited coating film is provided on the surface of the substrate.

[0021] The cathodic electrodeposition coating composition of the present invention is aqueous. The term "aqueous" in relation to the electrodeposition coating composition of the present invention preferably means, for the purposes of the present invention, that water is present as the main constituent of any solvent and / or diluent present in the electrodeposition coating composition, and the amount thereof is preferably at least 35% by mass based on the total mass of the electrodeposition coating composition of the present invention. An organic solvent may additionally be present in a lower proportion, preferably in an amount of <20% by mass.

[0022] The electrodeposition coating composition of the present invention preferably contains water in a fraction of at least 40% by mass, more preferably at least 50% by mass, still more preferably at least 60% by mass, still more preferably at least 65% by mass, particularly at least 70% by mass, and most preferably at least 75% by mass, each in each case relative to the total mass of the electrodeposition coating composition.

[0023] The electrodeposition coating composition of the present invention preferably contains an organic solvent in a fraction in the range of <10% by mass, more preferably in the range of 0 to <10% by mass, very preferably in the range of 0 to <7.5% by mass or 0 to <5% by mass or 0 to 2% by mass, each in each case relative to the total mass of the electrodeposition coating composition. Examples of such organic solvents include heterocyclic, aliphatic, or aromatic hydrocarbons, monohydric or polyhydric alcohols, particularly methanol and / or ethanol, ethers, esters, ketones, and amides, such as N-methylpyrrolidone, N-ethylpyrrolidone, dimethylformamide, toluene, xylene, butanol, ethylene glycol, propylene glycol, and butyl glycol ethers and 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 such as butyl glycol, or propylene glycol ethers such as butoxypropanol or phenoxypropanol.

[0024] The solid content of the electrodeposition coating composition of the present invention is preferably in the range of 5 to 35% by mass, more preferably 7.5 to 30% by mass, very preferably 10 to 27.5% by mass, more specifically 12.5 to 25% by mass, most preferably 15 to 22.5% by mass or 15 to 20% by mass, and these are in each case based on the total mass of the electrodeposition coating composition. The solid content, in other words, the non-volatile fraction, is measured by the method described below.

[0025] The electrodeposition coating composition of the present invention preferably has a pH in the range of 2.0 to 10.0, more preferably in the range of 2.5 to 9.5 or 2.5 to 9.0, very preferably in the range of 3.0 to 8.5 or 3.0 to 8.0, more specifically in the range of 2.5 to 7.5 or 3.5 to 7.0, particularly preferably in the range of 4.0 to 6.5, and most preferably in the range of 3.5 to 6.5 or 5.0 to 6.0.

[0026] The electrodeposition coating composition preferably contains component (a) in an amount in the range of 15 to 85% by mass, more preferably 20 to 80% by mass, very preferably 25 to 77.5% by mass, more specifically 30 to 75% by mass or 35 to 75% by mass, most preferably 40 to 70% by mass or 45 to 70% by mass or 50 to 70% by mass, and these are in each case based on the total solid content of the electrodeposition coating composition. Alternatively, the electrodeposition coating composition of the present invention preferably contains component (a) in an amount in the range of 1 to 80% by mass, more preferably 2.5 to 75% by mass, very preferably 5 to 70% by mass, more specifically 7.5 to 65% by mass, most preferably 8 to 60% by mass or 10 to 50% by mass, and these are in each case based on the total mass of each electrodeposition coating composition in the coating bath.

[0027] The electrodeposition coating composition preferably contains component (b) in an amount in the range of 0.01 to 10% by mass, more preferably 0.05 to 5.0% by mass, very preferably 0.1 to 2.5% by mass, more specifically 0.2 to 1.4% by mass, most preferably 0.4 to 1.2% by mass or 0.6 to 1% by mass, and these are in each case based on the total mass of the electrodeposition coating composition.

[0028] When the amount of component (b) is small, in some cases, edge corrosion may deteriorate. On the other hand, when the amount of component (b) is large, in some cases, the surface roughness may increase, and thus the homogeneity may deteriorate.

[0029] It is preferable that the electrodeposition coating composition of the present invention further contains at least one crosslinking agent component (c). The component (c) is preferably present in an amount in the range of 5 to 45% by mass, more preferably 6 to 42.5% by mass, very preferably 7 to 40% by mass, more specifically 8 to 37.5% by mass or 9 to 35% by mass, most preferably 10 to 35% by mass, particularly preferably 15 to 35% by mass, and these are in each case based on the total solid content of the electrodeposition coating composition. Alternatively, when the electrodeposition coating composition of the present invention further contains at least one crosslinking agent component (c), the component (c) is preferably present in an amount in the range of 0.5 to 30% by mass, more preferably 1 to 25% by mass, very preferably 1.5 to 20% by mass, more specifically 2 to 17.5% by mass, most preferably 2.5 to 15% by mass, particularly preferably 3 to 10% by mass, and these are in each case based on the total mass of each electrodeposition coating composition in the coating bath.

[0030] The fractions, expressed in mass%, of all components (a), (b) and water contained in the electrodeposition coating composition of the present invention, and of any additional components that may be present, such as component (c), in total amount to 100% by mass relative to the total mass of the electrodeposition coating composition.

[0031] The relative mass ratio of component (a) and (c) (when component (c) is present) to each other in the electrodeposition coating composition is preferably in the range of 5:1 to 1.1:1, more preferably in the range of 4.5:1 to 1.1:1, very preferably in the range of 4:1 to 1.2:1, more specifically in the range of 3:1 to 1.5:1.

[0032] The composition of the present invention contains at least one, preferably exactly one, binder dispersion (I). As is known to those skilled in the art, an electrocoating composition usually contains such a binder dispersion, i.e., an aqueous dispersion containing at least one polymer as a binder. Further, the composition of the present invention contains at least one pigment paste (II). Again, as is known to those skilled in the art, an electrocoating composition usually contains such a pigment paste.

[0033] The different essential and optional components of the composition of the present invention are described below. Details of the binder dispersion (I) and the pigment paste (II) are also further described below.

[0034] Component (a) Component (a) is at least one cathodically depositable polymer and preferably functions as at least one binder in the electrocoating composition of the present invention. At the same time, component (a) may also function as an abrasive resin. Details will be described later.

[0035] As long as it is cathodically depositable, any polymer is suitable as a binder and thus as component (a). Preferred are poly(meth)acrylates, (meth)acrylate copolymers, and epoxide polymers.

[0036] Preferably, component (a) of the electrocoating composition of the present invention contains at least one epoxide-amine adduct and / or is at least one epoxide-amine adduct.

[0037] The epoxide-amine adduct for the purposes of the present invention is the reaction product of at least one epoxide resin and at least one amine. The epoxide resin used is more specifically based on bisphenol A and / or its derivatives. The amine reacting with the epoxide resin is a primary and / or secondary amine or its salt and / or the salt of a tertiary amine.

[0038] At least one epoxy - amine adduct (a) used as component (a) is preferably a cationic, epoxy - based amine - modified resin. The preparation of such cationic, amine - modified epoxy - based resins is known and is described, for example, in DE3518732, DE3518770, EP0004090, EP0012463, EP0961797B1, and EP0505445B1. The cationic, epoxy - based amine - modified resin is preferably understood to be a reaction product of at least one polyepoxide having preferably two or more, for example three, epoxy groups, and at least one amine, preferably at least one primary and / or secondary amine. Particularly preferred polyepoxides are polyglycidyl ethers of polyphenols prepared from polyphenols and epihalohydrins. The polyphenols used are especially bisphenol A and / or bisphenol F. Other suitable polyepoxides are polyglycidyl ethers of polyhydric alcohols such as 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 polyepoxides used may be modified polyepoxides. A modified polyepoxide is understood to be a polyepoxide in which some of the reactive functional groups have reacted with at least one modifying compound. Examples of such modifying compounds are as follows.

[0039] 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, alicyclic and / or aromatic dicarboxylic acids of various chain lengths (e.g., adipic acid, sebacic acid, isophthalic acid, or dimerized fatty acids), hydroxyalkyl carboxylic acids (e.g., lactic acid, dimethylolpropionic acid), and carboxyl - containing polyesters, or ii) Compounds containing diamines having an amino group or a secondary amino group such as diethylamine or ethylhexylamine, for example, N,N'-dialkylalkylene-diamines such as dimethylethylenediamine, N,N'-dialkyl-polyoxyalkyleneamines such as N,N'-dimethylpolyoxypropylenediamine, cyanoalkylated alkylene diamines such as bis-N,N'-cyanoethyl ethylenediamine, cyanoalkylated polyoxyalkyleneamines such as bis-N,N'-cyanoethyl polyoxypropylenediamine, polyaminoamides such as Versamide, especially amino-terminal reaction products of diamines (e.g., hexamethylenediamine), polycarboxylic acids, especially dimer fatty acids and monocarboxylic acids, more specifically fatty acids, or reaction products of 1 mole of diaminohexane and 2 moles of monoglycidyl ether or monoglycidyl ester, especially glycidyl esters of α-branched fatty acids such as versatic acid, or iii) Hydroxyl group-containing compounds 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-isopropylidene bis(p-phenoxy)-2-propanol, trimethylolpropane, pentaerythritol, or amino alcohols such as triethanolamine, methyldiethanolamine, or hydroxyl group-containing alkyl ketimines such as aminomethylpropane-1,3-diol methyl isobutyl ketimine or tris(hydroxymethyl)aminomethane cyclohexanone ketimine, and 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 esterified with the hydroxyl groups of epoxy resins in the presence of sodium methoxide.

[0040] Examples of amines that can be used in the preparation of component (a) are, for example, 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. The amine that can be used may contain other functional groups as long as it does not interrupt the reaction between the amine and the epoxy groups of the optionally modified polyepoxide and does not cause gelation of the reaction mixture. Secondary amines are preferably used. The dilutability in water and the charge required for electrodeposition are generated by protonation with a water-soluble acid (e.g., boric acid, formic acid, acetic acid, lactic acid, alkylsulfonic acid (e.g., methanesulfonic acid)), preferably acetic acid and / or formic acid. A further means of introducing a cationic group into the optionally modified polyepoxide is to react the epoxy groups of the polyepoxide with an amine salt.

[0041] The epoxy-amine adduct that can be used as component (a) is preferably a reaction product of an epoxy resin based on bisphenol A and a primary and / or secondary amine or its salt and / or a salt of a tertiary amine.

[0042] Component (b) The electrodeposition coating composition of the present invention contains at least one alkoxylated polyethyleneimine. Preferably, exactly one kind of alkoxylated polyethyleneimine is contained.

[0043] Polyethyleneimine is well known to those skilled in the art. Polyethyleneimine is a polymer having repeating units formally composed of reacted aziridine molecules, i.e., amine functional groups separated by ethylene (-CH2-CH2-) spacer units. In the case of linear polyethyleneimine, all the amino groups in the chain are secondary amino groups, but in branched polyethyleneimine, depending on the nature and degree of branching, tertiary amino groups (representing the branch points) also exist within the molecule. When the chain / polymer is cleaved, primary amino groups are of course formed.

[0044] The synthetic methods for such polyethyleneimine are also well known and are carried out by ring-opening polymerization of aziridine. Depending on the reaction conditions, the degree of branching varies. For details, reference may be made to the widely known and accessible established scientific literature and general knowledge.

[0045] Polyethyleneimine (b) is alkoxylated polyethyleneimine. Thus, the N-H functional groups of the primary and secondary amino groups present in such polyethyleneimine are modified by suitable components and react, whereby each alkoxylation occurs. As an example, the nucleophilic center (N-H functional group) of the amino group is reacted with ethylene oxide (oxirane), and polyethyleneimine is alkoxylated (here ethoxylated) via ring-opening polymerization of ethylene oxide.

[0046] The degree of alkoxylation (i.e., the average number of polymer alkoxy moieties (i.e., O-alkyl moieties) per alkoxylation modification of the amino group), and the statistical distribution of the size and length of the individual alkoxylation modifications of the amino group also depend on the stoichiometric conditions and reaction conditions. As a repetition, for details, reference may be made to the well-known scientific literature and the knowledge of those skilled in the art.

[0047] Obviously, each alkoxylation modification consumes one protonic N-H functional group, thus leading from a primary amino group to a secondary amino group, or from a secondary amino group to a tertiary amino group.

[0048] Since the tertiary amino group is usually more alkaline than the primary and secondary amino groups, the whole molecule tends to be more protonated at a given pH value. More specifically, at a pH value preferred in the context of an electrodeposition coating material, for example, a pH value of 3.5 to 7.0 or 4.0 to 6.5, a certain degree of protonation may already be achieved (i.e., the pH value, on the one hand, guarantees the protonation state of the dispersed binder polymer preferably applied in the context of a cathodic deposition paint (i.e., these polymers are stabilized in the dispersion and move to the cathode when an electric current is applied), and on the other hand, it means that deposition can occur on the substrate without any defects or, for example, redissolution of the material). Therefore, with regard to water dispersibility, the presence of these amino groups is advantageous because the protonation behavior under pH conditions is suitable for cathodic deposition paints.

[0049] Preferably, the alkoxylated polyethyleneimine (b) has a branched characteristic, i.e., the polyethyleneimine moiety of component (b) is a branched polyethyleneimine moiety. Thus, even if it still contains secondary and primary amino groups only for statistical reasons, it also contains (also) tertiary amino groups due to the branched characteristic. Furthermore, the branched characteristic of the polyethylene moiety may result in at least a partially spherical, dendritic structure. And this corresponds to a relatively compact molecular core of the branched polyethyleneimine moiety and a shell-like structure containing a plurality of N-H functional groups accessible for alkoxylation.

[0050] Preferably, at least one alkoxylated polyethyleneimine (b) is ethoxylated, propoxylated and / or mixed ethoxylated / propoxylated polyethyleneimine. More preferably, at least one alkoxylated polyethyleneimine (b) is ethoxylated polyethyleneimine. Both types of alkoxylation are readily available and conveniently achievable, but they also contribute to enhancing the water dispersibility (which is important in the context of the aqueous electrodeposition paint of the present invention). This is especially the case for ethoxylated polyethyleneimine. Furthermore, both show, for example, a steric effect as a shell-like structure, affect the interaction with the electrodeposition paint of the present invention, and can ensure the compatibility with other components of the electrodeposition paint of the present invention, such as component (a), due to the alkalinity of the amine functional groups of the alkoxylated polyethyleneimine (b). Therefore, if the degree of alkoxylation is insufficient or lacking, the compatibility with electrodeposition coating deteriorates, and for example, the paint bath may become unstable.

[0051] The degree of alkoxylation (i.e., the average number of polymerized alkoxy moieties (i.e., O-alkyl moieties) per alkoxylation modification of the amino group) is preferably selected in the range of 5 to 100, more preferably 10 to 90 or 15 to 70. Within these ranges of alkoxylation, for statistical reasons only, a high proportion (or all) of the N-H functional groups are consumed by the alkoxylation modification, that is, the above effects (a small amount of N-H functional groups, high water dispersibility at a pH value highly suitable in the context of cathodic deposition paints, core-shell-like structure, steric effect, etc.) are achieved to a considerable extent, which is obvious.

[0052] The degree of alkoxylation is determined by 13C NMR spectroscopy and by comparing the signal intensities of (i) the carbon signal assigned to the alkoxylated alkyl - O unit (e.g., (CH2 - CH2 - O) in the case of ethoxylation type) of the alkoxylation and (ii) the carbon signal assigned to the carbon at the alpha position relative to the hydroxyl end group of such alkoxylation.

[0053] The number average molecular weight (Mn) of the alkoxylated polyethyleneimine (b) may, for example, range from 1000 to 30000 g / mol, for example from 2500 to 25000 g / mol, preferably from 5000 to 20000 g / mol, or even more preferably from 7500 to 15000 g / mol. The number average molecular weight is determined via gel permeation chromatography (eluent: tetrahydrofuran / triethylamine (0.5% by volume), calibrated against polymethyl-methacrylate standards).

[0054] Component (b) may be applied in the form of an aqueous dispersion or solution. Thus, such a dispersion or solution is added during the production of the binder dispersion (I) and / or the pigment paste (II).

[0055] Since component (b) itself contains a significant portion of basic amino groups, it is clear that simply mixing it with water will ultimately raise the pH to the basic range. Therefore, the addition of an acid may be necessary to finally achieve the above-mentioned preferred pH values and ranges of the composition of the present invention. Preferred for the introduction of acidity are those known in the art and the aforementioned water-soluble acids, such as acetic acid or methanesulfonic acid. By this means, an equilibrium state is created that contains at least a partially protonated amino group portion of component (b) in water.

[0056] Component (b), particularly preferred component (b), is an ethoxylated branched polyethyleneimine and is available commercially, for example, under the trade name Sokalan HP, for example Sokalan HP20 (registered trademark).

[0057] These commercial products are provided for applications such as laundry, dishwashing, and cleaning. However, extremely surprisingly, they also have a significant positive effect on the edge corrosion protection of the electrocoating materials described at the beginning.

[0058] Any component (c) As component (c), at least one crosslinking agent can be present in the electrodeposition coating composition. This crosslinking agent is selected from the group consisting of blocked polyisocyanates, free polyisocyanates, amino resins, and mixtures thereof. The component (c) is different from the component (a).

[0059] The term "blocked polyisocyanate" is known to those skilled in the art. The blocked polyisocyanate that can be used is a polyisocyanate having at least two isocyanate groups (diisocyanate in the case of exactly two isocyanate groups), preferably a polyisocyanate having more than two, for example, 3 to 5 isocyanate groups. Here, the isocyanate groups have reacted, and as a result, the formed blocked polyisocyanate is stable at room temperature, that is, a temperature of 18 to 23 °C, particularly with respect to amino groups such as hydroxyl groups, primary amino groups, and / or secondary amino groups, but at high temperatures, for example, 80 °C or higher, 110 °C or higher, 130 °C or higher, 140 °C or higher, 150 °C or higher, 160 °C or higher, 170 °C or higher, or 180 °C or higher, it reacts with the formation of conversion and urethane and / or urea bonds respectively.

[0060] In the preparation of the blocked polyisocyanate, any desired organic polyisocyanate suitable for crosslinking can be used. Preferred isocyanates include (hetero)aliphatic, (hetero)alicyclic, (hetero)aromatic, or (hetero)aliphatic-(hetero)aromatic isocyanates. Preferred polyisocyanates are those containing 2 to 36 carbon atoms, particularly 6 to 15 carbon atoms. Preferred examples include ethylene 1,2-ethylenediisocyanate, 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, ω,ω’-diisocyanatodipropyl ether, cyclobutene 1,3-diisocyanate, cyclohexane 1,3- and 1,4-diisocyanate, 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (isophorone diisocyanate, IPDI), 1,4-diisocyanatomethyl-2,3,5,6-tetramethyl-cyclohexane, decahydro-8-methyl(1,4-methanonaphthalene-2(or 3),5-ylenedimethylene diisocyanate, hexahydro-4,7-methanoindane-1(or 2),5(or 6)-ylenediisocyanate, hexahydro-4,7-methanoindane-1(or 2),5(or 6)-ylene diisocyanate, hexahydrotoluene 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 (H 12MDI), 4,4'-diisocyanato-3,3',5,5'-tetramethyldicyclohexylmethane, 4,4'-diisocyanato-2,2',3,3',5,5',6,6'-octamethyldicyclohexylmethane, ω,ω'-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-diisocyanatohexane, 1,3-diisocyanatomethylcyclohexane, 1,4-diisocyanatomethylcyclohexane, 2,5(2,6)-bis(isocyanatomethyl)bicyclo[2.2.1]heptane (NBDI), and any mixtures of these compounds. Higher isocyanate-functional polyisocyanates may also be used. Examples thereof include trimerized hexamethylene diisocyanate and trimerized isophorone diisocyanate, more specifically the corresponding isocyanurates. Furthermore, it is also possible to use mixtures of polyisocyanates.

[0061] For the blocking of polyisocyanates, it is preferably possible to use any desired suitable aliphatic, cycloaliphatic, or aromatic alkyl monoalcohol. Examples thereof include aliphatic alcohols such as methyl, ethyl, chloroethyl, propyl, butyl, amyl, hexyl, heptyl, octyl, nonyl, 3,3,5-trimethylhexyl, decyl, and lauryl alcohol, cycloaliphatic alcohols such as cyclopentanol and cyclohexanol, and aromatic alkyl alcohols such as phenylcarbinol and methylphenylcarbinol. Similarly, suitable diols such as ethanediol, 1,2-propanediol, 1,3-propanediol, and / or polyols may also be used for the blocking of 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.

[0062] Tris(alkoxycarbonylamino)-1,3,5-triazine (TACT) is likewise known to those skilled in the art. It is known to use tris(alkoxycarbonylamino)-1,3,5-triazine as a crosslinking agent in coating compositions. For example, DE19712940A1 describes the use of such a crosslinking agent in basecoat materials. U.S. Patent No. 5,084,541 describes the preparation of corresponding compounds that can be used as component (c). Such triazines are included in the term "blocked polyisocyanate" for the purposes of the present invention.

[0063] Amino resins (aminoplast resins) are likewise known to those skilled in the art. The amino resin to be used is preferably a melamine resin, more specifically a melamine-formaldehyde resin, which is likewise known to those skilled in the art. However, it is preferred not to use amino resins such as melamine-formaldehyde resins as crosslinking agent (c). Accordingly, the electrodeposition coating composition of the present invention preferably does not contain amino resins such as melamine-formaldehyde resins.

[0064] The electrodeposition coating composition of the present invention is preferably used as a one-component (1K) coating composition. For this reason, the electrodeposition coating composition of the present invention preferably does not contain free polyisocyanate.

[0065] Pigments and / or fillers The electrodeposition coating composition of the present invention contains at least one pigment and / or at least one filler.

[0066] The term "pigment" is known to those skilled in the art, for example, from DIN 55943 (date: October 2001). In the context of the present invention, "pigment" preferably refers to a component in the form of a powder or flake that is substantially, preferably completely insoluble in the surrounding medium, such as, for example, the electrocoating composition of the present invention. The pigment is preferably a colorant and / or substance that can be used as a pigment due to its magnetic, electrical, and / or electromagnetic properties. The pigment preferably differs from a "filler" in terms of its refractive index. In the case of a pigment, the refractive index is 1.7 or more.

[0067] The term "filler" is known to those skilled in the art, for example, from DIN 55943 (date: October 2001). For the purposes of the present invention, a "filler" is preferably a component that is substantially, preferably completely insoluble in the coating medium, such as, for example, the electrocoating composition of the present invention, and is used in particular to increase the volume. The "filler" in the context of the present invention preferably differs from a "pigment" in terms of its refractive index. In the case of a filler, the refractive index is less than 1.7.

[0068] Any conventional pigment known to those skilled in the art may be used. Examples of suitable pigments include inorganic coloring pigments and organic coloring pigments. Examples of suitable inorganic coloring pigments include white pigments such as titanium dioxide, zinc white, zinc sulfide or lithopone, black pigments such as carbon black, iron manganese black or spinel black, colored 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, iron oxide red, cadmium sulfoselenide, molybdate red or ultramarine red, brown iron oxide, mixed brown, spinel phase and corundum phase or chrome orange, or iron oxide yellow, nickel titanium yellow, chrome titanium yellow, cadmium sulfide, cadmium zinc sulfide, chrome yellow or bismuth vanadate. Further inorganic coloring pigments include silicon dioxide, aluminum oxide, aluminum oxide hydrate, particularly boehmite, titanium dioxide, zirconium oxide, cerium oxide, and mixtures thereof. Examples of suitable organic coloring pigments include monoazo pigments, disazo pigments, anthraquinone pigments, benzimidazole pigments, quinacridone pigments, quinophthalone pigments, diketopyrrolopyrrole 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.

[0069] Any conventional filler known to those skilled in the art may be used. Examples of suitable fillers are kaolin, dolomite, calcite, chalk, calcium sulfate, barium sulfate, graphite, silicates such as magnesium silicate, especially the corresponding phyllosilicates such as hectorite, bentonite, montmorillonite, talc and / or mica, silica, especially fumed silica, hydroxides such as aluminum hydroxide or magnesium hydroxide. Examples of kaolin include commercial products such as ASP200 (non-fired kaolin, manufactured by BASF) or KaMin2000C (fired kaolin, manufactured by KaMin) (ASP200 is recommended). Organic fillers such as textile fibers, cellulose fibers, polyethylene fibers or polymer powders may also be applied. For further details, see Roempp Lexikon Lacke und Druckfarben, Georg Thieme Verlag, 1998, pages 250 ff., "Filler".

[0070] The total content of the pigment and the filler relative to the total mass of the electrodeposition coating composition of the present invention is preferably in the range of 0.1 to 20.0% by mass, more preferably 0.1 to 15.0% by mass, very preferably 0.1 to 10.0% by mass, particularly preferably 0.1 to 5.0% by mass, and more specifically 0.1 to 2.5% by mass.

[0071] The pigment and / or filler is incorporated into the electrodeposition coating composition in the form of pigment paste (II). It is possible and preferred to use one pigment paste containing both one or more pigments and / or fillers. Such pastes generally contain at least one polymer used as a grinding resin. Thus, it is preferred that there is at least one such polymer present that is used as a grinding resin in the electrodeposition coating composition of the present invention. It is also possible for at least one polymer (a) used as a binder in the electrodeposition coating composition to additionally function as a grinding resin in pigment paste (II). The grinding resin is preferably an epoxide-amine adduct, which can correspond to and / or be included in the definition of component (a) as outlined above. The polymer used as a grinding resin preferably has building blocks that interact with the surface of the pigment. Thus, the grinding resin preferably has the effect of an emulsifier. In many cases, a quaternary ammonium compound is incorporated for the purpose of improving the properties of the grinding resin. In addition to the grinding resin, further conventional additives such as wetting agents or dispersions (any component (e) described later) and solvents (water and organic co-solvents) may also be included. The production of the pigment paste includes a grinding / milling step. Thereby, the pigment and / or filler is preferably milled together with the grinding resin and further components / solvents to form the pigment paste. Often, a catalyst (any component (d) described later) is also added before the grinding / milling step to ensure proper integration and effectiveness of the catalyst. To produce the finished electrodeposition coating composition, this paste is mixed with the remaining constituents, in particular the binder dispersion (I). The use of the pigment paste advantageously leads to greater flexibility in electrodeposition coating. Because the pigment / filler and binder of the electrodeposition coating composition can easily be adapted to the actual requirements at any time via the amount of the pigment paste.

[0072] As described above, in one embodiment of the present invention, the pigment paste (II) contains at least one component (b). The polyethyleneimine (b) may, in principle, be added at any position and time during the preparation of the pigment paste, for example, before or after grinding / pulverization. However, it is preferred to add the component (b) before the grinding / pulverization step. Often, the production of the pigment paste involves adding solid components (especially pigments and fillers, and catalysts) after the addition of all non-solid components (i.e., liquid components), and then grinding / pulverizing. It has been observed that it is advantageous to add the polyethyleneimine (b) directly before the first addition of the solid components. After the addition of all components, grinding / pulverization is carried out.

[0073] Any further optional components The electrodeposition coating composition of the present invention preferably contains at least one component (d) catalyst, for example, a metal-containing catalyst such as a tin-containing catalyst or a bismuth-containing catalyst in particular. The optionally included catalyst is even more preferably a bismuth-containing catalyst. Particularly preferably, a bismuth-containing catalyst such as bismuth(III) oxide, basic bismuth(III) oxide, bismuth(III) hydroxide, bismuth(III) carbonate, bismuth(III) nitrate, bismuth(III) subnitrate (basic bismuth(III) nitrate), bismuth(III) salicylate and / or bismuth(III) subsalicylate (basic bismuth(III) salicylate), and mixtures thereof can be used. Particularly preferably, it is a water-insoluble bismuth-containing catalyst. More specifically preferably, it is bismuth(III) subnitrate. The electrodeposition coating composition of the present invention contains at least one bismuth-containing catalyst, preferably in an amount such that the bismuth(III) content (calculated as bismuth metal) is in the range of 10 ppm to 20,000 ppm based on the total mass of the electrodeposition coating of the present invention. The amount of bismuth calculated as metal is determined by inductively coupled plasma - optical emission spectrometry (ICP - OES) in accordance with DIN EN ISO 11885 (date: September 2009).

[0074] Depending on the desired use, the electrodeposition coating composition of the present invention may contain 11 or more commonly used additional additives as one or more optional components (e). Component (e) is different from any of components (a) to (d). Preferably, these additives are wetting agents, emulsifiers, dispersants, surfactants, surface-active compounds such as surfactants, flow control aids, solubilizers, defoamers, rheology aids, antioxidants, stabilizers, preferably heat stabilizers, process stabilizers, and UV and / or light stabilizers, softeners, plasticizers, and mixtures of the aforementioned additives. The additive content can vary greatly depending on the purpose of use. The additive content is preferably in the range of 0.1 to 20.0% by mass, more preferably 0.1 to 15.0% by mass, very preferably 0.1 to 10.0% by mass, particularly preferably 0.1 to 5.0% by mass, and more specifically 0.1 to 2.5% by mass, based on the total mass of the electrodeposition coating composition of the present invention.

[0075] As described above, the composition of the present invention contains at least one binder dispersion (I). The binder dispersion (I) contains at least one component (a). Also, the binder dispersion (I) usually contains the aforementioned additional optional components, particularly component (c). Also, different components (d) are usually included. In addition to water, further organic co-solvents may be part of the binder dispersion (I).

[0076] In a preferred embodiment, the binder dispersion (I) contains at least one component (e) selected from the group consisting of polymer softeners and surface-active additives. Preferred polymer softeners are, for example, alkoxylated bisphenol A, preferably alkoxylated bisphenols such as ethoxylated bisphenol A. Preferred surface-active additives are, for example, polydimethylsiloxanes such as polydimethylsiloxane-poly(ethylene oxide-co-propylene oxide)-copolymers. In a preferred embodiment, both of the aforementioned components (e) are included in the binder dispersion (I).

[0077] As described above, in one embodiment of the present invention, the binder dispersion (I) contains at least one component (b). The polyethyleneimine (b) may, in principle, be added at any position and time during the preparation of the binder dispersion (I). As is known, the production of a binder dispersion containing a polymer (a), water and further components such as, for example, component (c) or (e) and an organic solvent involves different steps of adding the components in individual sequences, whereby one or more intermediate and / or final stirring and / or dispersion steps are included within the addition procedure. The polyethyleneimine (b) may, for example, be introduced as the first component or as one of the first components. Also, the polyethyleneimine (b) may be added at an intermediate position before and after the intermediate dispersion step. Although extremely obvious, the polyethyleneimine (b) may also be added at the final position, for example, even immediately before or after the final stirring / dispersing step. Preferably, the polyethyleneimine (b) is added at a position before at least one further dispersion step is carried out.

[0078] Kit of parts A further subject of the present invention is a kit of parts for producing an aqueous cathodic electrodepositable coating composition, the kit of parts comprising the following: (I) at least one binder dispersion comprising at least one cathodic electrodepositable polymer (a); and (II) at least one pigment paste comprising at least one pigment and / or filler and comprising at least one alkoxylated polyethyleneimine (b) is part of at least one binder dispersion (I) and / or part of at least one pigment paste (II).

[0079] Thus, the kit of parts comprises at least two different parts, namely the binder dispersion (I) and the pigment paste (II). At least one of these separate parts contains polyethyleneimine (b).

[0080] The present invention also relates to the following steps: - providing at least one binder dispersion (I) comprising at least one cathode-precipitable polymer (a); - providing at least one pigment paste (II) comprising at least one pigment and / or filler, wherein the binder dispersion (I) and / or the pigment paste (II) comprises at least one alkoxylated polyethyleneimine (b); - mixing the binder dispersion (I), the pigment paste (II) and any further potential components of the composition A method for producing a cathode-precipitable electrodeposition coating composition is provided.

[0081] It is extremely clear that all the essential and preferred features and embodiments described above in the context of the composition of the present invention are equally applicable to the kits of parts and the manufacturing methods.

[0082] Electrodeposition method A further subject of the present invention is a method for at least partially coating a conductive substrate by cathodic electrodeposition, comprising at least steps (1) to (5), namely: (1) immersing the conductive substrate at least partially in an electrodeposition bath containing the electrodeposition coating composition of the present invention; (2) connecting the substrate as a cathode; (3) depositing a coating film obtained from the electrodeposition coating composition on the substrate using a direct current; (4) removing the coated substrate from the electrodeposition bath, and (5) baking the coating film deposited on the substrate A method comprising the steps is provided.

[0083] Any of the above preferred embodiments related to the electrodeposition coating composition of the present invention is also a preferred embodiment of the method of the present invention described above for at least partially coating a conductive substrate by cathodic electrodeposition using this electrodeposition coating composition.

[0084] Preferably, the above method includes a step (4.1) of rinsing the painted substrate, for example, with DI water, between steps (4) and (5). Although this step is extremely obvious, it is for cleaning the substrate, that is, removing the residual paint that has not been sufficiently deposited on the substrate.

[0085] The method of the present invention is particularly suitable for electrocoating automobile vehicle bodies or parts thereof, and further for each metal substrate. Therefore, a preferred substrate is an automobile vehicle body or a part thereof. Since the electrocoating composition of the present invention is particularly useful for obtaining excellent edge protection, as a preferred embodiment, metal substrates having relatively many such edges can be mentioned. Such substrates are in particular metal automotive component parts such as, for example, lateral control arms, spring-loaded control arms or dampers. Such component parts may be cast iron parts or may be manufactured by other established methods known in the art. Furthermore, such substrates are metal automobile bodies, for example, automobile bodies that are partially stamped to cut out specific parts or form specific shapes and therefore contain relatively many edges. Thus, in a preferred embodiment of the present invention, the substrate is selected from the above-mentioned substrates having many edges.

[0086] As already mentioned above, the remarkable edge protection provided by the present invention is particularly useful in the context of metal substrates that have at least partially edges that have not been post-treated, such as sanding or polishing, that is, edges that remain relatively sharp. Thus, in another preferred embodiment of the present invention, the substrate is selected from the above-mentioned substrates that have edges that have not been at least partially post-treated, such as sanding or polishing, or other treatments, to reduce the edges, and further edges that are referred to as without sanding or polishing.

[0087] As the conductive substrate used in the present invention, any commonly used conductive substrate known to those skilled in the art is suitable. The conductive substrate used in the present invention is preferably a metal substrate, more preferably selected from the group consisting of steel, preferably bare steel, cold rolled steel (CRS), hot rolled steel, zinc plated steel such as hot dip galvanized steel (HDG), alloy zinc plated steel (e.g., galvalume, galvannealed or galfan) and steel selected from the group consisting of aluminum plated steel, aluminum and magnesium, and Zn / Mg alloys and Zn / Ni alloys. A particularly preferred substrate is a part of a vehicle body or a complete vehicle body for automobile manufacturing.

[0088] Before using each of the conductive substrates in step (1) of the method of the present invention, the substrate is preferably cleaned and / or degreased.

[0089] The conductive substrate used in the present invention is preferably a pretreated substrate, for example, a substrate pretreated with at least one metal phosphate such as zinc phosphate. This type of pretreatment by phosphate treatment is usually carried out after cleaning the substrate and before electrocoating the substrate in step (1), and is a conventional pretreatment process particularly in the automotive industry. However, pretreatment methods other than phosphate treatment, such as thin film pretreatment based on zirconium oxide or typical silanes, are also possible.

[0090] During the execution of steps (1), (2), and (3) of the method of the present invention, the electrodeposition coating composition of the present invention is cathodically deposited on the area of the substrate immersed in the bath in step (1). In step (2), the substrate is connected as the cathode, and a voltage is applied between the substrate and at least one counter electrode. The counter electrode is located in the deposition bath or exists separately from the bath, for example, by an anion-permeable anion exchange membrane. In this way, the counter electrode functions as an anode. When an electric current flows between the anode and the cathode, a firmly adhering coating film is deposited on the cathode, that is, on the immersed portion of the substrate. The voltage applied here is preferably in the range of 50 to 500 volts. When steps (1), (2), and (3) of the method of the present invention are executed, the electrodeposition coating bath preferably has a bath temperature in the range of 20 to 45 °C.

[0091] The baking temperature in step (5) is preferably in the range of 100 to 210 °C, more preferably 120 to 205 °C, very preferably 120 to 200 °C, more specifically 125 to 195 °C or 125 °C to 190 °C, and most preferably 130 to 185 °C or 140 to 180 °C.

[0092] After performing step (5) of the method of the present invention, one or more additional coating films can be applied on the baked coating film obtained after step (5). For example, a primer and / or a filler can be applied, and subsequently a base coat and a clear coat can be applied.

[0093] Therefore, the method of the present invention includes at least one additional step (6), that is, (6) the step of at least partially applying at least one additional coating composition different from the composition applied in step (1) on the baked coating film obtained after step (5) is preferably included.

[0094] Substrate A further subject of the present invention is a conductive substrate at least partially coated with the baked electrodeposition coating of the present invention. This baked coating corresponds to the baked coating film obtained after step (5) of the method of the present invention.

[0095] All of the foregoing preferred embodiments related to the electrocoating composition of the present invention and the method of the present invention are also preferred embodiments related to at least partially coated substrates of the present invention described above.

[0096] Of course, the baked electrocoating layer produced from the electrocoating composition of the present invention is also an object of the present invention.

[0097] Method 1. Determination of non-volatile fraction The non-volatile fraction (solids or solids content) is determined in accordance with DIN EN ISO 3251 (date: June 2019). This involves weighing 1 g of the sample into a pre-dried aluminum dish, drying the dish containing the sample in a drying oven at 180 °C for 30 minutes, cooling in a desiccator, and weighing again. The residue relative to the total amount of the sample used corresponds to the non-volatile fraction (% or mass %).

[0098] 2. VDA climate change test (DIN EN ISO 11997-1:2018-01) This climate change test is used to determine the corrosion resistance of the coating on the substrate. The climate change test is carried out in 10 to 20 so-called cycles.

[0099] If the coating to be tested is present on a perforated metal substrate, these holes simulate a realistic metal substrate with a relatively large number of edge / edge zones. Also, for substrates with holes that have not been post-treated, such as sanding or polishing, before starting any pretreatment and coating process, these substrates are more difficult in terms of coating and thus corrosion edge protection. The degree of corrosion at the edges of these holes (also called "corrosion at the edge of the hole" or "edge corrosion") is visually evaluated by observing the degree / portion of corrosion at the edge of the hole after the climate change test (on an evaluation scale from 1 to 5, where "5" means 100% corrosion (the entire edge of the hole is corroded) and "1" means 0% corrosion).

[0100] Before conducting the climate change test, if a cut is made with a knife to the substrate through the coating of the sample to be tested, the substrate will corrode along the cut during the climate change test. Therefore, the degree of under-film corrosion of the sample can be tested according to DIN EN ISO4628-8 (03-2013). As corrosion progresses, the coating will be infiltrated more or less during the test. The degree of erosion (in mm) serves as an indicator of the corrosion resistance of the coating (also referred to as scribing corrosiveness).

[0101] Furthermore, each of the evaluation results shown below is the average value of 3 to 5 individual test results. Each individual test result was generated by an individual panel (i.e., the coated test substrate), and each individual panel thus presented 7 individual holes. The individual test result itself for one individual panel regarding hole protection is the analytical average value of the 7 individual holes.

[0102] 3. Salt Spray Test The corrosion resistance of the coating may be determined by a salt spray test. The salt spray test is carried out in accordance with DIN EN ISO9227 NSS (date: September 2012) for the coated substrate to be investigated. The sample to be investigated is continuously housed in a chamber at a temperature of 35 °C for 1008 hours or 2016 hours, and a mist is generated from a 5% concentration sodium chloride solution with a pH controlled in the range of 6.5 - 7.2. The mist adheres to the sample to be investigated, and the sample is covered with a corrosive salt water film.

[0103] When the coating under test is present on a perforated metal substrate, these holes are similar to a realistic metal substrate having a relatively large number of edges / edge zones. Also, for substrates with holes whose edges are not sanded / polished before starting any pretreatment and coating process, these substrates are similar to substrates having a large number of edges / edge zones that are not sanded / polished, and thus are more difficult in terms of coating and corrosion edge protection. The degree of corrosion at the edges of these holes (also called "corrosion at the hole edge" or "edge corrosion") is visually evaluated by observing the degree / portion of corrosion at the hole edge after a climate change test (on an evaluation scale from 1 to 5, where "5" means 100% corrosion (the entire hole edge is corroded) and "1" means 0% corrosion).

[0104] Before the salt spray test according to DIN EN ISO9227 NSS, if the coating of the sample under investigation is cut to the substrate with a blade cut, the substrate will corrode along the cut line during the DIN EN ISO9227 NSS salt spray test, so the sample can be investigated for the level of corrosive erosion of DIN EN ISO4628-8 (03-2013). As a result of the progress of corrosion, the coating is eroded more or less during the test. The degree of erosion (in mm) becomes an index indicating the resistance of the coating to corrosion (also called scribing corrosivity).

[0105] Furthermore, each of the evaluation results shown below is the average value of 3 to 5 individual test results. Each individual test result is generated by an individual panel (i.e., the coated test substrate), and thus each individual panel presented seven individual holes. The individual test result itself for one individual panel regarding hole protection is the analysis average value of the seven individual holes.

[0106] 4. Surface roughness The surface roughness is measured in accordance with DIN EN10049:2014-03. A low value [micrometer] clearly reflects that the surface roughness is extremely low, and thus the smoothness and homogeneity of the coating are excellent.

[0107] Furthermore, each of the evaluation results shown below is the average value of 3 to 5 individual test results. Each individual test result is generated by an individual panel (i.e., a painted test substrate).

Example

[0108] The present invention will be further described by the following examples, but should not be construed as limiting the scope thereof.

[0109] 1. Preparation of Aqueous Cathodic Electrodeposition Paint Composition 1.1 Pigment Paste (II) The standard pigment paste P1 commonly used in the preparation of aqueous cathodic electrodeposition paint compositions was prepared by (i) mixing each of the constituent components with a dissolver and (ii) grinding the mixture from (i) under conventional conditions using a standard mill. In this way, all liquid constituent components were added in step (i), and then the solid components were introduced.

[0110] Pigment paste P1 contained, as a grinding resin, an aqueous dispersion of an epoxy-amine adduct (component (a), solid content 40.4%). Further, paste P1 contained bismuth subsalicylate (III) as a catalyst, carbon black as a black pigment, kaolin (ASP200) as a filler, and further constituent components, in particular, water and additives conventional in aqueous cathodic electrodeposition paint compositions. The solid content of pigment paste P1 was 62.0%.

[0111] Furthermore, pigment paste P2 was prepared. The preparation was carried out in principle in the same manner as for paste P1. However, as the final position of the liquid component, Sokalan (registered trademark) HP20 (manufactured by BASF) (component (b), solid content 80 - 82%) was added. The effective amount of component (b) was 2% by mass based on the total mass of pigment paste P2.

[0112] Sokalan® HP (manufactured by BASF) was a branched ethoxylated polyethyleneimine having an ethoxylation degree of 28 and a number average molecular weight of 8600 g / mol (for the measurement method, refer to the detailed description of the present invention above).

[0113] 1.2 Binder dispersion (I) As the standard binder dispersion (I), System B1, which is customarily applied in an electrocoating composition, was used. The binder dispersion contained an aqueous dispersion of an epoxy-amine adduct (which is also component (a), but different from the epoxy-amine adduct applied to the pigment paste) as the binder resin, a blocked isocyanate as the crosslinking component (c), and further contained additional constituents such as particularly customary additives, organic co-solvents, and water. The constituents of the binder dispersion were added in an individual order, thereby performing different mixing (dissolving) steps and two dispersion stages. The solid content of the binder dispersion was 36% (binder dispersion B1).

[0114] Furthermore, binder dispersions B2 to B4 containing an alkoxylated polyethyleneimine were produced. The preparation was carried out in principle like that of dispersion B1. The deviations and differences were as follows.

[0115] Binder dispersion B2: After the preparation of binder dispersion B1, Sokalan® HP20 (manufactured by BASF) was added with stirring.

[0116] Binder dispersion B3: During the production of binder dispersion B1, the component that was added last before the first dispersion stage was the crosslinking component (c). In the preparation of binder dispersion B3, Sokalan® HP20 (manufactured by BASF) was added immediately after the addition of the crosslinking agent (c) and before the start of the first dispersion stage.

[0117] Binder dispersion B4: The preparation of binder dispersion B1 included a second dispersion step, and the dispersion rate in this step was faster than that in the first dispersion step. In the preparation of binder dispersion B4, Sokalan® HP20 (manufactured by BASF) was added immediately before the second dispersion step.

[0118] The effective amount of component (b) in binder dispersions B2 to B4 was 2.0% by mass based on the total mass of each binder dispersion.

[0119] 1.3 Electrodeposition coating composition An electrodeposition coating composition was prepared using the above pigment paste and binder dispersion. The comparative example system was prepared from pigment paste P1 and binder dispersion B1 (not containing component (b), i.e., alkoxylated polyethyleneimine), while the composition of the present invention contained component (b) in the pigment paste or the binder dispersion.

[0120] Details of each bath and their constituent components are shown in Table 1. By mixing the constituent components listed in the table in this order, an electrodeposition coating composition for coating (Item 2 below) was formed.

[0121]

Table 1

[0122] As observed from the above, the amount of component (b) in the composition (E-1) of the present invention was 2000 ppm based on the total mass of the bath in each case, while in the compositions (E-2) to (E-4) of the present invention, the amount was approximately 0.95% by mass (or 9500 ppm).

[0123] 2. Electrodeposition coating of the substrate A coating film obtained from the electrodeposition coating composition described in Item 1.3 above was deposited on a cathodically connected test panel at a deposition voltage of 220 V and a coating bath temperature of 32 °C, and then baked at a substrate temperature of 175 °C for 15 minutes to obtain a coating layer thickness of 20 micrometers.

[0124] As a test panel, a cold-rolled steel substrate pretreated with a phosphate treatment composition (spray coating of a zinc manganese phosphate treatment composition) was used (Gardobond® GB26S 6800OC). Before the pretreatment, seven individual holes were drilled in the test panel. These holes and their edges were not sanded or polished respectively, and each resembled the non-sanded / polished edge of an actual substrate.

[0125] Table 2 shows the details investigated for the cured coatings on the prepared substrates according to item 3 below.

[0126]

Table 2

[0127] 3. Investigation of the properties of the coated substrates The corrosion resistance of the cured coatings on the substrates was investigated by the method described above. More specifically, for the coatings on the substrates, investigations were carried out regarding multiple or all of the following properties.

[0128] - Corrosion at the edge of the hole (end corrosion), salt spray test for 1008 hours (SST1008) - End corrosion, VDA climate change test for 10 cycles (VDA10) - Scribe corrosion, SST1008 - Surface roughness.

[0129] Table 4 shows each data regarding the corrosion test.

[0130]

Table 3

[0131] From the results, it can be seen that the compositions and cured coatings of the present invention each show significantly improved end corrosion prevention. Similarly, the influence on scribe corrosiveness is negligible or at least not so high.

[0132] Furthermore, the results regarding the surface roughness of all investigated systems were mainly in the acceptable range between 0.5 and 1.0, meaning that no relevant adverse effects on the surface roughness were observed.

Claims

1. The following components, (I) at least one binder dispersion containing at least one cathode-precipitable polymer (a), and (II) at least one pigment paste containing at least one pigment and / or filler, An aqueous cathode-precipitable electrodeposition coating composition comprising: The production of the electrodeposition coating composition includes mixing the binder dispersion (I) and the pigment paste (II), The composition also includes at least one alkoxylated polyethyleneimine (b), and At least one alkoxylated polyethyleneimine (b) is part of at least one of the binder dispersion (I) and / or at least one of the pigment paste (II). A coating composition.

2. The coating composition according to claim 1, wherein the polyethyleneimine moiety of the at least one alkoxylated polyethyleneimine (b) is a branched polyethyleneimine moiety.

3. The coating composition according to claim 1 or 2, wherein the at least one alkoxylated polyethyleneimine (b) is an ethoxylated, propoxylated and / or mixed ethoxylated / propoxylated polyethyleneimine.

4. The coating composition according to claim 3, wherein the at least one alkoxylated polyethyleneimine (b) is an ethoxylated polyethyleneimine.

5. The coating composition according to claim 1 or 2, wherein the at least one alkoxylated polyethyleneimine (b) has an alkoxylation degree (i.e., the average number of polymer alkoxy moieties (i.e., O-alkyl moieties) per alkoxylation modification of amino groups) of 10 to 100.

6. The coating composition according to claim 1 or 2, wherein the at least one alkoxylated polyethyleneimine (b) has a number average molecular weight of 2,500 to 30,000 g / mol.

7. The coating composition according to claim 1 or 2, wherein the amount of component (b) contained in the composition is in the range of 0.01 to 10% by mass based on the total mass of the electrodeposition coating composition.

8. The coating composition according to claim 1 or 2, wherein at least one epoxide-amine adduct is present as at least one polymer (a).

9. The coating composition according to claim 1 or 2, wherein at least one epoxide-amine adduct is present as at least one polymer (a) and is a reaction product of at least one epoxy resin based on bisphenol A and at least one primary and / or secondary amine and / or its salt and / or at least one tertiary amine or its salt.

10. The coating composition according to claim 1 or 2, comprising (c) at least one crosslinking agent component.

11. The coating composition according to claim 10, wherein at least one blocked polyisocyanate is present as at least one crosslinking agent component (c).

12. The following: (I) at least one binder dispersion containing at least one cathodically depositable polymer (a), and (II) at least one pigment paste containing at least one pigment and / or filler containing A kit of parts for producing an aqueous cathodically depositable electrodeposition coating composition, A kit of parts, wherein at least one alkoxylated polyethyleneimine (b) is part of said at least one binder dispersion (I) and / or part of said at least one pigment paste (II).

13. The following steps - Providing at least one binder dispersion (I) comprising at least one cathode-depositable polymer (a); - Providing at least one pigment paste (II) comprising at least one pigment and / or filler, wherein said binder dispersion (I) and / or said pigment paste (II) comprises at least one alkoxylated polyethyleneimine (b); - Mixing said binder dispersion (I), said pigment paste (II) and any further potential components of said composition A method for producing a cathode-depositable electrodeposition coating composition comprising.

14. A method for at least partially coating a conductive substrate by cathodic electrodeposition, comprising at least steps (1) to (5), namely: (1) Immersing said conductive substrate at least partially in an electrodeposition coating bath comprising the electrodeposition coating composition according to claim 1 or 2; (2) Connecting said substrate as a cathode; (3) Depositing a coating film obtained from said electrodeposition coating composition onto said substrate using a direct current; (4) Removing said coated substrate from said electrodeposition coating bath; and (5) Baking said coating film deposited on said substrate. A method comprising.

15. At least one further step (6), namely: (6) Applying at least partially onto the baked coating film obtained after step (5) at least one further coating composition different from said composition applied in step (1). The method according to claim 13, characterized in that it comprises

16. A conductive substrate coated in a form at least partially baked with an electrocoating composition according to claim 1 and / or manufactured according to claim 12, and / or obtainable by the method according to claim 13.

17. A method of using at least one alkoxylated polyethyleneimine as defined in claim 1 or 2 for improving the edge corrosion protection of a conductive substrate having a baked coating film, wherein the baked coating film is obtained from an aqueous cathodic electrodepositable electrocoating composition, and the composition comprises at least one cathodic depositable polymer (a) in addition to the at least one alkoxylated polyethyleneimine.

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