Electrodeposition coating material composition comprising alkoxylated polyethyleneimine

Abstract

The invention relates to an aqueous cathodically depositable electrodeposition coating material composition comprising at least one binder dispersion (I) comprising at least one cathodically depositable polymer (a) and at least one pigment paste (II) comprising at least one pigment and / or filler, wherein the production of the electrodeposition coating material composition comprises mixing the binder dispersion (I) and the pigment paste (II), and wherein the composition further comprises at least one alkoxylated polyethyleneimine (b) and wherein the at least one alkoxylated polyethyleneimine (b) is part of the at least one binder dispersion (I) and / or part of the at least one pigment paste (II).

Description

[0001] The present invention relates to an aqueous cathodically depositable electrodeposition coating material composition, comprising: at least one binder dispersion (I) comprising at least one cathodically depositable polymer (a) and at least one pigment paste (II) comprising at least one pigment and / or filler, wherein the dispersion (I) and / or the paste (II) comprises at least one alkoxylated polyethyleneimine (b). The present invention also relates to a kit of parts for producing an aqueous cathodically depositable coating material composition and also a method for producing such a composition. In addition, the present invention relates to a method for at least partially coating a conductive substrate by cathodically electrodeposition coating, the method comprising at least steps (1) to (5), comprising the step (1) of at least partially immersing the substrate in an electrodeposition coating bath, the electrodeposition coating bath comprising the electrodeposition coating material composition of the present invention. In addition, the present invention relates to a conductive substrate, which is at least partially coated with a baked electrodeposition coating material composition of the present invention and / or is obtainable by the method of the present invention. Background Art

[0002] In the automotive industry, metal parts used for manufacturing often have to be protected from corrosion. The requirements in terms of the corrosion control to be achieved are very stringent, not least because manufacturers often offer a multi-year guarantee against rust perforation. This corrosion control is usually achieved by coating the parts or the substrates used to manufacture them with at least one coating suitable for this purpose.

[0003] In order to be able to ensure the necessary corrosion control, it is common practice to apply an electrodeposition coating film to a metal substrate, which substrate may have been pretreated by phosphating and / or by other kinds of pretreatment. Electrodeposition coating (electrocoating) materials are coating materials that contain polymers as binders, optionally crosslinking agents, pigments and / or fillers, and often additives. Generally, there are electrocoating materials that can be deposited anodically and cathodically. Anodic electrodeposition coating compositions that contain metal effect pigments are disclosed, for example, in WO 2006 / 117189 A1. However, cathodically depositable materials are of the greatest importance in industrial coating and in particular in automotive finishing. In cathodic electrodeposition coating, the substrate to be coated is immersed in an electrocoating bath and connected as a cathode. The bath has an anode as a counter electrode. The particles of the electrocoating material are stabilized with a positive charge and deposited on the cathode to form a coating film. After deposition, the coated substrate is removed from the electrocoating bath, rinsed with water and the coating film is baked, i.e. thermally cured.

[0004] Cathodically depositable electrocoating materials are known in the prior art, for example from EP 1 041 125 A1, DE 197 03 869 A1 and WO 91 / 09917 A2.

[0005] As already described, the main purpose of cathodically depositable electrocoating materials is the corrosion protection of metallic substrates. In the automotive industry, these substrates are in particular automotive bodies and also metal component parts, like transverse control arms, spring-loaded control arms or dampers. These substrates inherently include multiple edges due to their geometry and the processes (e.g. stamping) carried out before the coating step. These edges remain a major challenge for proper corrosion protection by electrodeposition coating processes. Although the protection of surfaces and planes can be called very well established, the prior art does lack the best technical solutions at the edges. The reason is quite self-evident, even taking into account the peculiarities of electrodeposition and its advantages, it is challenging to ensure sufficient film formation on the edges, for example by changing the viscosity during the softening of the film during curing, while ensuring sufficient material flow to achieve the desired leveling of the film on the surfaces and planes. For economic reasons, this effect is even more significant and relevant, because currently in industrial coating processes, post-processing steps like, for example, sanding and polishing processes of the substrate edges are often omitted, which means that sharp edges are not rounded, but remain unchanged and are therefore even more difficult to be coated. The result is a reduction in coating thickness and thus reduced corrosion protection at these edges.

[0006] One measure to address this problem is to increase the viscosity of the deposited electrodeposition material and also to accelerate the viscosity increase during curing. However, this in turn often leads to a simultaneous increase in the surface roughness of the coating, since the material cannot level out after application and during curing. However, increased surface roughness is an effect to be avoided in the automotive coating industry, since its compensation either requires rigorous efforts during the subsequent coating formation or is simply not possible, resulting in unacceptable aesthetic properties of the resulting automotive multilayer coating. In fact, avoiding high surface roughness, while achieving good corrosion protection, is a major challenge in the context of electrodeposition coating in the automotive industry.

[0007] It would therefore be desirable to be able to provide an electrodeposition coating material which allows for increased corrosion protection of the edges of metal substrates without negatively affecting the surface roughness of the electrocoated substrate.

[0008] US 2010 / 0143632 A1 describes a composition comprising a mixture of polyethyleneimine and poly(meth)acrylic acid for obtaining corrosion protection of a metal substrate. Edge corrosion protection is not described. In addition, no disclosure is made about any content of an electrocoating composition, not to mention an electrocoating composition that can be deposited cathodically. This is consistent with the following findings (as presented in the following example section), i.e. such polyethyleneimine does not work in an electrocoating material composition that can be deposited cathodically, i.e. such an electrocoating material composition that can be deposited cathodically is non-depositable.

[0009] question

[0010] It is therefore an object of the present invention to provide an electrodeposition coating material which allows the formation of a smooth and uniform film during its application to a metal substrate, whereby the resulting coating exhibits excellent corrosion resistance in the edge region.

[0011] Solution

[0012] This object has been solved by the subject matter of the claims of the present application and by its preferred embodiments disclosed in the present description, ie by the subject matter described herein.

[0013] The first subject of the present invention is an aqueous cathode-depositable electrodeposition coating material composition comprising

[0014] (I) at least one binder dispersion comprising at least one cathodically depositable polymer (a), and

[0015] (II) at least one pigment paste comprising at least one pigment and / or filler,

[0016] The preparation of the electrodeposition coating material composition comprises mixing the binder dispersion (I) and the pigment paste (II), and

[0017] wherein the composition further comprises at least one alkoxylated polyethyleneimine (b), and

[0018] The at least one alkoxylated polyethyleneimine (b) is part of the at least one binder dispersion (I) and / or part of the at least one pigment paste (II).

[0019] Another subject of the invention is a kit of parts for producing an aqueous cathodically depositable electrodeposition coating material composition comprising

[0020] (I) at least one binder dispersion comprising at least one cathodically depositable polymer (a), and

[0021] (II) at least one pigment paste comprising at least one pigment and / or filler,

[0022] The at least one alkoxylated polyethyleneimine (b) is part of the at least one binder dispersion (I) and / or part of the at least one pigment paste (II).

[0023] Furthermore, the subject of the present invention is a method for producing a cathodically depositable electrodeposition coating material composition, which comprises

[0024] - providing (I) at least one binder dispersion comprising at least one cathodically depositable polymer (a)

[0025] - providing at least one pigment paste (II) comprising at least one pigment and / or filler,

[0026] wherein the binder dispersion (I) and / or the pigment paste (II) comprises at least one alkoxylated polyethyleneimine (b),

[0027] - Mixing the binder dispersion (I), the pigment paste (II) and any further potential components of the composition.

[0028] Another subject of the present invention is a method for at least partially coating an electrically conductive substrate by cathodic electrodeposition coating, the method comprising at least steps (1) to (5), namely

[0029] (1) at least partially immersing the conductive substrate in an electrodeposition coating bath containing the electrodeposition coating material composition of the present invention,

[0030] (2) connecting the substrate as a cathode,

[0031] (3) depositing a coating film obtained from the electrodeposition coating material composition on the substrate using direct current,

[0032] (4) removing the coated substrate from the electrodeposition coating bath, and

[0033] (5) Baking the coating film deposited on the substrate.

[0034] Another subject of the present invention is an electrically conductive substrate which is at least partially coated with a baked electrodeposition coating material composition according to the invention and / or is obtainable by a process according to the invention.

[0035] It has been surprisingly found that the electrodeposition coating material composition of the present invention allows excellent edge corrosion protection of conductive (i.e. metal) substrates. Furthermore, it has been surprisingly found that, in addition to the improved edge corrosion protection, the uniformity of the surface film is still of high quality, i.e. surface roughness is avoided. In summary, therefore, the present invention brings together two key properties of electrodeposition coatings, i.e. high edge corrosion protection and excellent film uniformity. DETAILED DESCRIPTION

[0036] In the sense of the present invention, the term "comprising" in relation to the electrodeposition coating material composition of the present invention, for example, includes but does not exclusively have the meaning of "consisting of". Thus, for example, with respect to the electrodeposition coating material composition of the present invention, in addition to components (a), (b) and water, it is possible to include therein one or more additional components specified below and optionally included in the electrodeposition coating material composition of the present invention. In each case, all components may be present in its preferred embodiment, as specified below. "Consisting of" may also be referred to as "only comprising" or "exclusively comprising", i.e., "comprising" may be referred to as a general term including the specific term "consisting of".

[0037] Electrodeposition coating material composition of the present invention

[0038] The cathodically depositable aqueous electrodeposition coating material composition of the present invention (hereinafter also referred to as the electrodeposition coating material composition of the present invention or the composition of the present invention) comprises at least one binder dispersion (I) (also referred to as component (a)) comprising at least one cathodically depositable polymer (a) and at least one pigment paste (II) comprising at least one pigment and / or filler. At least one of components (I) and (II), preferably exactly one, 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 composition of the present invention further comprises water. The terms "electrodeposition coating material composition" and "electrodeposition coating composition" used herein are interchangeable.

[0039] The cathodically depositable aqueous electrodeposition coating material composition of the present invention is suitable for at least partially coating a conductive substrate with an electrodeposition coating composition, meaning that it is suitable for at least partially applying to a substrate surface of a conductive substrate and its application results in an electrodeposition coating film on the substrate surface.

[0040] The cathode-depositable electrodeposition coating material composition of the present invention is aqueous. For the purposes of the present invention, the term "aqueous" in relation to the electrodeposition coating material composition of the present invention is preferably understood to mean water, as a solvent and / or as a diluent, as the main component 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 present invention. Organic solvents may additionally be present in a smaller proportion, preferably in an amount of <20 wt.-%.

[0041] The electrodeposition coating composition according to the invention preferably comprises a water fraction of at least 40 wt.-%, more preferably at least 50 wt.-%, still more preferably at least 60 wt.-%, yet more preferably at least 65 wt.-%, in particular at least 70 wt.-%, most preferably at least 75 wt.-%, in each case based on the total weight of the electrodeposition coating composition.

[0042] The electrodeposition coating composition of the invention preferably comprises an organic solvent fraction of <10 wt.-%, more preferably in the range of from 0 to <10 wt.-%, very preferably in the range of from 0 to <7.5 wt.-% or from 0 to <5 wt.-% or from 0 to 2 wt.-%, in each case based on the total weight of the electrodeposition coating composition. Examples of such organic solvents include heterocyclic, aliphatic or aromatic hydrocarbons, monohydric or polyhydric alcohols, in particular methanol and / or ethanol, ethers, esters, ketones and amides, for example N-methylpyrrolidone, N-ethylpyrrolidone, dimethylformamide, toluene, xylene, butanol, ethylene glycol, propylene glycol and butyl glycol ether 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, glycol ethers like butyl glycol or propylene glycol ethers like butoxypropanol or phenoxypropanol.

[0043] The solid content of the electrodeposition coating material composition of the present invention is preferably in the range of from 5 to 35wt.-%, more preferably from 7.5 to 30wt.-%, very preferably from 10 to 27.5wt.-%, more particularly from 12.5 to 25wt.-%, most preferably from 15 to 22.5wt.-% or from 15 to 20wt.-%, in each case based on the total weight of the electrodeposition coating composition. The solid content, in other words the non-volatile part, is determined according to the method described below.

[0044] The electrodeposition coating material composition of the present invention 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, particularly preferably in the range of from 4.0 to 6.5, most preferably in the range of from 3.5 to 6.5 or from 5.0 to 6.0.

[0045] The electrodeposition coating material of the composition comprises component (a) in an amount preferably in the range of from 15 to 85 wt.-%, more preferably from 20 to 80 wt.-%, very preferably from 25 to 77.5 wt.-%, more particularly from 30 to 75 wt.-% or from 35 to 75 wt.-%, most preferably from 40 to 70 wt.-% or from 45 to 70 wt.-% or from 50 to 70 wt.-%, in each case based on the total solid content of the electrodeposition coating composition. Alternatively, the electrodeposition coating material composition of the present invention comprises component (a) in an amount preferably in the range of from 1 to 80 wt.-%, more preferably from 2.5 to 75 wt.-%, very preferably from 5 to 70 wt.-%, more particularly from 7.5 to 65 wt.-%, most preferably from 8 to 60 wt.-% or from 10 to 50 wt.-%, in each case based on the total weight of the electrodeposition coating material composition and the coating bath, respectively.

[0046] The electrodeposition coating material of the composition comprises component (b) in an amount preferably in the range of from 0.01 to 10 wt.-%, more preferably from 0.05 to 5.0 wt.-%, very preferably from 0.1 to 2.5 wt.-%, more particularly from 0.2 to 1.4 wt.-%, most preferably from 0.4 to 1.2 wt.-% or from 0.6 to 1 wt.-%, in each case based on the total weight of the electrodeposition coating composition.

[0047] In the case of lower amounts of component (b), reduced edge corrosion protection may result in some cases. On the other hand, in the case of higher amounts of component (b), increased surface roughness and thus lower homogeneity may result in some cases.

[0048] In case the electrodeposition coating material composition of the invention additionally comprises at least one crosslinker component (c), it is preferred that said component (c) is preferably present in an amount in the range of from 5 to 45 wt.-%, more preferably from 6 to 42.5 wt.-%, very preferably from 7 to 40 wt.-%, more particularly from 8 to 37.5 wt.-% or from 9 to 35 wt.-%, most preferably from 10 to 35 wt.-%, particularly preferably from 15 to 35 wt.-%, in each case based on the total solids content of the electrodeposition coating composition. Alternatively, in case the electrodeposition coating composition of the present invention additionally comprises at least one crosslinker component (c), said component (c) is preferably present in an amount in the range of from 0.5 to 30 wt.-%, more preferably from 1 to 25 wt.-%, very preferably from 1.5 to 20 wt.-%, more particularly from 2 to 17.5 wt.-%, most preferably from 2.5 to 15 wt.-%, especially preferably from 3 to 10 wt.-%, in each case based on the total weight of the electrodeposition coating material composition and the coating bath.

[0049] The fractions in wt.-% of all components (a), (b) and water contained in the electrodeposition coating composition of the invention, and also any additional components (e.g. component (c)) which may be present, add up to 100 wt.-%, based on the total weight of the electrodeposition coating material composition.

[0050] The relative weight ratio of components (a) and (c) (if component (c) is present) to each other in the electrodeposition coating material composition is preferably in the range of from 5:1 to 1.1:1, more preferably in the range of from 4.5:1 to 1.1:1, very preferably in the range of from 4:1 to 1.2:1, and more particularly in the range of from 3:1 to 1.5:1.

[0051] The composition of the present invention comprises at least one, preferably exactly one, binder dispersion (I). As known to those skilled in the art, electrodeposition coating compositions often contain such binder dispersions, i.e. aqueous dispersions containing at least one polymer as binder. In addition, the composition of the present invention contains at least one pigment paste (II). Again, as known to those skilled in the art, electrodeposition coating compositions often contain such pigment pastes.

[0052] In the following, different essential and optional components of the composition of the present invention are described.More details about the binder dispersion (I) and the pigment paste (II) will also be presented further below.

[0053] Component (a)

[0054] Component (a) is at least one cathodically depositable polymer, which preferably acts as at least one binder in the electrodeposition coating material composition of the present invention. At the same time, component (a) may also act as a grinding resin, as will be outlined in more detail below.

[0055] Any polymer is suitable as binder and thus as component (a) as long as it is cathodically depositable. Preference is given to poly(meth)acrylates, (meth)acrylate copolymers, and epoxide polymers.

[0056] Preferably, component (a) of the electrodeposition coating composition of the present invention comprises and / or is at least one epoxide-amine adduct.

[0057] The epoxide-amine adducts used for the purposes of the present invention are the reaction products of at least one epoxy resin and at least one amine. The epoxy resins used are more particularly those based on bisphenol A and / or its derivatives. The amines reacted with the epoxy resins are primary and / or secondary amines or their salts and / or salts of tertiary amines.

[0058] 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, amine-modified, epoxide-based resins is known and described in, for example, DE 35 18 732, DE 35 18 770, EP 0 004 090, EP 0 012 463, EP 0 961 797 B1 and EP0 505 445 B1. Cationic, epoxide-based, amine-modified resins are understood to be preferably the reaction product of at least one polyepoxide preferably having two or more (e.g. three) epoxy groups and at least one amine, preferably at least one primary amine and / or secondary amine. Particularly preferred polyepoxides are polyglycidyl ethers of polyphenols prepared from polyphenols and epihalohydrins. The polyphenols used can be bisphenol A and / or bisphenol F in particular. Other suitable polyepoxides are polyglycidyl ethers of polyols such as, for example, ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,4-propylene glycol, 1,5-pentanediol, 1,2,6-hexanetriol, glycerol and 2,2-bis(4-hydroxycyclohexyl)propane. The polyepoxides used may also be modified polyepoxides. Modified polyepoxides are to be understood as 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:

[0059] 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 different chain lengths (e.g. adipic acid, sebacic acid, isophthalic acid, or dimer fatty acids), hydroxyalkylcarboxylic acids (e.g. lactic acid, dimethylolpropionic acid), and polyesters containing carboxyl groups, or

[0060] ii) compounds containing amino groups, such as diethylamine or ethylhexylamine or diamines with secondary amino groups, for example N,N'-dialkylalkylenediamines, such as dimethylethylenediamine, N,N'-dialkyl-polyoxyalkylenediamines, such as N,N'-dimethylpolyoxypropylenediamine, cyanoalkylated alkylenediamines, such as bis-N,N'-cyanoethylethylenediamine, cyanoalkylated polyoxyalkylenediamines, such as bis-N,N'-cyanoethylpolyoxypropylenediamine, polyaminoamides, such as, for example, tertiary carbonamides, especially diamines (e.g. hexamethylenediamine), amino-terminated reaction products of polycarboxylic acids, especially dimerized fatty acids and monocarboxylic acids, more especially fatty acids, or reaction products of one mole of diaminohexane with two moles of monoglycidyl ethers or monoglycidyl esters, especially glycidyl esters of α-branched fatty acids, such as versatile carbonic acid, or

[0061] 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-isopropylbis(p-phenoxy)-2-propanol, trimethylolpropane, pentaerythritol or amino alcohols, such as triethanolamine, methyldiethanolamine, or alkyl ketimines containing hydroxyl groups, such as aminomethylpropane-1,3-diol methylisobutylketimine or tris(hydroxymethyl)aminomethanecyclohexanoneketimine, and also polyglycol ethers, polyester polyols, polyether polyols, polycaprolactone polyols, polycaprolactam polyols of varying functionality and molecular weight, or

[0062] iv) Saturated or unsaturated fatty acid methyl esters which are esterified with the hydroxyl groups of the epoxy resin in the presence of sodium methoxide.

[0063] For example, examples of amines that can be used to prepare component (a) are monoalkylamines 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 amines that can be used may also include other functional groups, provided that they do not destroy the reaction of the amine with the epoxy groups of the optionally modified polyepoxide and do not cause gelation of the reaction mixture. Preferably secondary amines are used. The charge required for water dilutability and electrodeposition can be 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). Another way to introduce cationic groups into the optionally modified polyepoxide is to react the epoxy groups of the polyepoxide with an amine salt.

[0064] The epoxide-amine adducts which can be used as component (a) are preferably reaction products of epoxy resins based on bisphenol A with primary and / or secondary amines or their salts and / or salts of tertiary amines.

[0065] Component (b)

[0066] The electrodeposition coating material composition of the present invention comprises at least one alkoxylated polyethyleneimine. Preferably, it comprises exactly one type of alkoxylated polyethyleneimine.

[0067] Polyethyleneimines are well known to those skilled in the art. Polyethyleneimines are polymers with repeating units formally consisting of reacted aziridine molecules, i.e. amine functional groups separated by ethylene (-CH2-CH2-) spacer units. In the case of linear polyethyleneimines, the amino groups within the chain are all secondary amino groups, while in branched polyethyleneimines, depending on the branching characteristics and their degree, tertiary amino groups are also present within the molecule (branching points are then depicted). Quite obviously, the chain / polymer termination produces primary amino groups.

[0068] The synthesis of such polyethyleneimines is also well known and can be carried out by ring-opening polymerization of aziridine. Different reaction conditions lead to different degrees of branching. For details, reference is made to the widely known and available established scientific literature and general knowledge.

[0069] Polyethyleneimine (b) is an alkoxylated polyethyleneimine. Thus, the NH functional groups of the primary and secondary amino groups present in the polyethyleneimine itself are modified and reacted by suitable components to produce the corresponding alkoxylation. As an example, the nucleophilic center of the amino group (NH functional group) can react with ethylene oxide (ethylene oxide), thereby leading to the alkoxylation (here ethoxylation) of the polyethyleneimine via the ring-opening polymerization of ethylene oxide.

[0070] The degree of alkoxylation (i.e. the average number of polymerized alkoxy moieties (i.e. O-alkyl moieties) per alkoxylation modification on an amino group) and the statistical distribution of the size and length of the individual alkoxylation modifications of the amino group depend on the stoichiometric conditions and also the reaction conditions. Again, for details, reference is made to the scientific literature and knowledge familiar to the person skilled in the art.

[0071] Obviously, each alkoxylation modification consumes a protic NH function and thus results in a primary to a secondary amino group or a secondary to a tertiary amino group.

[0072] Since tertiary amino groups are generally more basic than primary and secondary amino groups, this leads to a tendency for the entire molecule to be more protonated at a given pH value. More specifically, a certain degree of protonation may already be achieved at the pH values ​​preferred in the context of electrodeposition coating materials, for example at pH values ​​of, for example, 3.5 to 7.0 or 4.0 to 6.5 (i.e., pH values ​​that on the one hand ensure the protonation state of the dispersed binder polymers preferably applied in the context of cathodically depositable coating materials, meaning that these polymers are stable in the dispersion and migrate to the cathode when an electric current is applied, and on the other hand allow deposition 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 of their protonation behavior under pH conditions suitable for cathodically depositable coating materials.

[0073] Preferably, the alkoxylated polyethyleneimine (b) has a branching character, i.e. the polyethyleneimine part of component (b) is a branched polyethyleneimine part. Therefore, due to the branching character, it (also) contains tertiary amino groups, even if only for statistical reasons, it may still contain secondary and primary amino groups. In addition, the branching character of the polyethylene part can produce at least partially spherical, dendritic structures. This in turn corresponds to a relatively compact molecular core of the branched polyethyleneimine part and a shell-like structure containing a plurality of easily accessible NH functional groups for alkoxylation.

[0074] 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. Although the alkoxylation of the two aforementioned types is easy to implement and conveniently feasible, they also contribute to enhanced water dispersibility (which is important in the context of the aqueous electrodeposition coating material of the present invention). This is especially true for ethoxylated polyethyleneimine. In addition, for example, they can show a steric effect as a shell-like structure, affecting the interaction with the electrodeposition coating material of the present invention and the alkalinity of the amine functional group of the alkoxylated polyethyleneimine (b), ensuring compatibility with other components of the electrodeposition coating material of the present invention, such as component (a). Therefore, insufficient or missing alkoxylation degree may lead to incompatibility with the electrodeposition coating, such as causing instability of the coating material bath.

[0075] The degree of alkoxylation (i.e. the average number of polymerized alkoxy moieties (i.e. O-alkyl moieties) per alkoxylation modification on the amino group) can preferably be selected in the range from 5 to 100, more preferably from 10 to 90 or from 15 to 70. Within these ranges of alkoxylation, a high proportion (or even all) of the NH functions are consumed by the alkoxylation modification, apparently only for statistical reasons, which means that the above-mentioned effects (low amount of NH functions, high water dispersibility at pH values ​​that are very suitable in the context of cathodically depositable coating materials, core-shell structure, steric effects, etc.) are achieved to a large extent.

[0076] The degree of alkoxylation is determined by 13C NMR spectroscopy and comparison of the signal intensities of (i) the carbon signal assignable to the alkoxylated alkyl-O unit (e.g., ethoxylated type (CH2-CH2-O)) and (ii) the carbon signal assignable to the alpha carbon of the terminal hydroxyl group of such alkoxylation.

[0077] The number average molecular weight (Mn) of the alkoxylated polyethyleneimine (b) may be, for example, in the range of from 1000 to 30000 g / mol, such as from 2500 to 25000 g / mol, preferably from 5000 to 20000 g / mol or even from 7500 to 15000 g / mol. The number average molecular weight is determined by gel permeation chromatography (eluent tetrahydrofuran / triethylamine (0.5 vol.-%), calibrated against polymethyl methacrylate standards).

[0078] Component (b) can 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).

[0079] Since component (b) itself contains a large part of basic amino groups, it is obvious that only mixing it with water will eventually lead to an increase in pH to the alkaline range. Therefore, in order to finally achieve the above-mentioned preferred pH value and range of the composition of the present invention, it may be necessary to add acid. Preferred are water-soluble acids as known in the art and as mentioned before, such as acetic acid or methanesulfonic acid, to introduce acidity. In this way, an equilibrium state comprising at least partially protonated amino moieties of component (b) in water is produced.

[0080] Component (b), particularly preferred component (b), is an ethoxylated and branched polyethyleneimine, such as is commercially available under the trade name Sokalan HP, such as Sokalan Available.

[0081] Although these commercially available products are provided for applications like laundry, dishwashing and cleaning, it is quite surprising that they also have a significant positive impact on the edge corrosion protection of electrodeposition coated materials as outlined in the introductory part.

[0082] Optional component (c)

[0083] At least one crosslinking agent may be present in the electrodeposition coating material composition as component (c), which 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).

[0084] The term "blocked polyisocyanate" is known to the skilled person. Blocked polyisocyanates that can be used are polyisocyanates having at least two isocyanate groups (diisocyanates in the case of exactly two isocyanate groups), but preferably having more than two, such as, for example, 3 to 5 isocyanate groups, wherein the isocyanate groups have reacted such that the blocked polyisocyanate formed is stable at room temperature (i.e. at a temperature of 18° C. to 23° C.), in particular with respect to hydroxyl groups and amino groups, such as primary and / or secondary amino groups, but reacts at elevated temperatures, such as, for example, at ≥80° C., ≥110° C., ≥130° C., ≥140° C., ≥150° C., ≥160° C., ≥170° C., or ≥180°, respectively, with conversion and formation of urethane and / or urea bonds.

[0085] In the preparation of blocked polyisocyanates, any desired organic polyisocyanates suitable for crosslinking can be used. The isocyanates used are preferably (hetero)aliphatic, (hetero)alicyclic, (hetero)aromatic or (hetero)aliphatic-(hetero)aromatic isocyanates. Preferred polyisocyanates are those containing 2 to 36, in particular 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)-trimethylhexamethylene 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, cyclobutylene 1,3-diisocyanate, cyclohexane 1,3- and 1,4-diisocyanate, 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (isophorone diisocyanate). cyanate, IPDI), 1,4-diisocyanatomethyl-2,3,5,6-tetramethyl-cyclohexane, decahydro-8-methyl (1,4-endomethylenenaphthalene-2 ​​(or 3), 5-endomethylene diisocyanate, hexahydro-4,7-endomethyleneindan-1 (or 2), 5 (or 6)-endomethylene diisocyanate, hexahydro-4,7-endomethyleneindan-1 (or 2), 5 (or 6)-endomethylene diisocyanate, hexahydro-4,7-endomethyleneindan-1 (or 2), 5 (or 6)-endomethylene 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 124-Diisocyanatomethyl)-2,3-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 also any mixtures of these compounds. It is also possible to use polyisocyanates having a higher isocyanate functionality. Examples thereof are trimerized hexamethylene diisocyanate and trimerized isophorone diisocyanate, more particularly the corresponding isocyanurates. Furthermore, it is also possible to use mixtures of polyisocyanates.

[0086] For the end-capping of polyisocyanates, any desired suitable aliphatic, alicyclic, or aromatic alkyl monoalcohols can be preferably used. Examples thereof are aliphatic alcohols such as methanol, ethanol, chloroethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, nonanol, 3,3,5-trimethylhexanol, decanol and lauryl alcohol; alicyclic alcohols such as cyclopentanol and cyclohexanol; aromatic alkyl alcohols such as benzyl alcohol and methylbenzyl alcohol. Similarly, suitable diols such as ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol and / or polyols can also be used for the end-capping of polyisocyanates. Other suitable end-capping 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.

[0087] Tris(alkoxycarbonylamino)-1,3,5-triazines (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 940A1 describes the use of such crosslinking agents in primer materials. U.S. Pat. No. 5,084,541 describes the preparation of corresponding compounds that can be used as component (c). For the purposes of the present invention, such triazines are covered by the term "blocked polyisocyanates".

[0088] Amino resins (amino plastic resins) are also known to the skilled person. The amino resin used is preferably a melamine resin, more particularly a melamine-formaldehyde resin, which is also known to the skilled person. However, preference is given to not using amino resins such as melamine-formaldehyde resins as crosslinking agents (c). Therefore, the electrodeposition coating material composition of the present invention preferably does not contain amino resins such as melamine-formaldehyde resins.

[0089] The electrodeposition coating material 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.

[0090] Pigments and / or fillers

[0091] The electrodeposition coating material composition of the present invention contains at least one pigment and / or at least one filler.

[0092] The term "pigment" is known to the skilled person, for example from DIN 55943 (date: October 2001). "Pigment" in the sense of the present invention preferably refers to components in the form of powders or flakes, which are substantially, preferably completely insoluble in the medium surrounding them, such as, for example, the electrodeposition coating material composition of the present invention. Pigments are preferably colorants and / or substances which can act as pigments due to their magnetic, electric and / or electromagnetic properties. Pigments differ from "fillers" preferably in their refractive index, the refractive index of pigments being ≥1.7.

[0093] The term "filler" is known to the skilled person, for example from DIN 55943 (date: October 2001). For the purposes of the present invention, a "filler" is preferably a component which is substantially, preferably completely, insoluble in the application medium (such as, for example, the electrodeposition coating material composition of the present invention) and which is used in particular to increase the volume. "Fillers" in the sense of the present invention preferably differ from "pigments" in their refractive index, the refractive index of fillers being <1.7.

[0094] Any conventional pigment known to the technician can 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 zinc lithopone; black pigments, such as carbon black, iron manganese black or spinel black; colored pigments, such as chromium oxide, hydrated chromium oxide 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, molybdenum chromium red or ultramarine red; iron oxide brown, mixed brown, spinel phase and corundum phase or chrome orange; or iron oxide yellow, nickel titanium yellow, chrome titanium yellow, cadmium sulfide, cadmium sulfide zinc, chrome yellow or bismuth vanadate. Other inorganic coloring pigments are silicon dioxide, aluminum oxide, hydrated aluminum oxide, especially boehmite, titanium dioxide, zirconium oxide, cerium oxide, and mixtures thereof. Examples of suitable organic colored pigments are monoazo pigments, disazo pigments, anthraquinone pigments, benzimidazole pigments, quinacridone pigments, quinoline yellow 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.

[0095] Any conventional filler known to the skilled person can be used. Examples of suitable fillers are kaolin, dolomite, calcite, chalk, calcium sulfate, barium sulfate, graphite, silicates such as magnesium silicate, especially corresponding phyllosilicates such as hectorite, bentonite, montmorillonite, talc and / or mica, silicon dioxide, especially fumed silica, hydroxides such as aluminum hydroxide or magnesium hydroxide. As examples of kaolin, commercial products like ASP 200 (non-calcined kaolin, BASF) or KaMin 2000C (calcined kaolin, KaMin) (preferably ASP 200) can be mentioned. In addition, organic fillers such as textile fibers, cellulose fibers, polyethylene fibers or polymer powders can be used. For further details, reference is made to Lexikon Lacke und Druckfarben, Georg Thieme Verlag, 1998, pp. 250 ff., “Fillers”.

[0096] Based on the total weight of the electrodeposition material coating composition of the present invention, the pigment plus filler content is preferably in the range of from 0.1 to 20.0 wt.-%, more preferably from 0.1 to 15.0 wt.-%, very preferably from 0.1 to 10.0 wt.-%, especially preferably from 0.1 to 5.0 wt.-%, and more particularly from 0.1 to 2.5 wt.-%.

[0097] Pigments and / or fillers are incorporated into the electrodeposition coating material composition in the form of a pigment paste (II). It is possible and preferred that a pigment paste (II) contains both one or more pigments and / or fillers. Such pastes typically include at least one polymer used as a grinding resin. Preferably, therefore, at least one such polymer used as a grinding resin is included in the electrodeposition coating composition of the present invention. It is possible that at least one polymer (a) used as a binder in the electrodeposition coating material composition can also additionally serve as a grinding resin in the pigment paste (II). The grinding resin in question is preferably an epoxide-amine adduct, as outlined above, which can correspond to and / or can be included under the definition of component (a). The polymer used as a grinding resin preferably has a structural unit that interacts with the surface of the pigment. Therefore, the grinding resin preferably has the effect of an emulsifier. In many cases, quaternary ammonium compounds are incorporated for the purpose of improving the properties of the grinding resin. In addition to the grinding resin, additional conventional additives such as wetting agents or dispersants (such as the optional component (e) described below) and also solvents (water and organic co-solvents) can also be included. The production of the pigment paste includes a grinding / milling step. Thus, pigment and / or filler are preferably ground together with grinding resin and other components / solvent to form pigment paste.Usually, before the grinding / milling step, catalyst (optional component (d) as described below) is also added to ensure the appropriate integration and effectiveness of catalyst.In order to produce final electrodeposition coating material composition, this paste is mixed with the remaining ingredients, particularly binder dispersion (I).The use of pigment paste advantageously causes the greater flexibility in electrodeposition coating, because the pigment / filler and the binder of the electrodeposition coating material composition can easily adapt to the requirements of practice at any time via the amount of pigment paste.

[0098] As mentioned above, in one embodiment of the invention, pigment paste (II) contains at least one component (b). In principle, polyethyleneimine (b) can be added at any position and time (for example before or after grinding / milling) in the preparation of pigment paste. However, it is preferred to add component (b) before the grinding / milling step. Usually, the production of pigment paste involves adding solid components (particularly pigment and filler and also catalyst) and then grinding / milling before adding all non-solid components (i.e. liquid components). It has been observed that it may be advantageous to directly add polyethyleneimine (b) before adding solid components for the first time. After adding all components, grind / mill.

[0099] Additional optional ingredients

[0100] The electrodeposition coating material composition of the present invention preferably comprises at least one component (d) catalyst, such as a metal-containing catalyst, such as a catalyst containing tin or bismuth in particular. The catalyst optionally included is even more preferably a bismuth-containing catalyst. Particularly preferably, a bismuth-containing catalyst can be used, such as bismuth (III) oxide, basic bismuth oxide (III), bismuth (III) hydroxide, bismuth (III) carbonate, bismuth (III) nitrate, bismuth (III) subnitrate (bismuth (III) subnitrate), bismuth (III) salicylate and / or bismuth (III) subsalicylate (bismuth (III) subsalicylate), and also mixtures thereof. Particularly preferred are water-insoluble, bismuth-containing catalysts. More particularly, preferred is bismuth (III) subnitrate. The electrodeposition coating material composition of the present invention preferably comprises at least one bismuth-containing catalyst in an amount such that the bismuth (III) content calculated as bismuth metal based on the gross weight of the electrodeposition coating material of the present invention is in the range of from 10ppm to 20 000ppm. The amount of bismuth, calculated as metal, can be determined in accordance with DIN EN ISO 11885 (date: September 2009) by inductively coupled plasma-atomic emission spectrometry (ICP-OES).

[0101] Depending on the desired application, the electrodeposition coating material composition of the present invention may contain one or more commonly used additional additives as one or more optional components (e). Component (e) is different from any one of components (a) to (d). Preferably, these additives are selected from the group consisting of: wetting agents, emulsifiers, dispersants, surface active compounds such as surfactants, flow control aids, solubilizers, defoamers, rheological aids, antioxidants, stabilizers (preferably heat stabilizers), process stabilizers, and UV and / or light stabilizers, tougheners, plasticizers, and mixtures of the above additives. The additive content can vary very widely depending on the intended use. Based on the gross weight of the electrodeposition material coating composition of the present invention, the additive content is preferably in the range of from 0.1 to 20.0 wt.-%, more preferably from 0.1 to 15.0 wt.-%, very preferably from 0.1 to 10.0 wt.-%, especially preferably from 0.1 to 5.0 wt.-%, and more particularly from 0.1 to 2.5 wt.-%.

[0102] As mentioned above, the composition of the present invention comprises at least one adhesive dispersion (I). Adhesive dispersion (I) contains at least one component (a). In addition, adhesive dispersion (I) often contains the other optional components mentioned above, particularly component (c). In addition, often comprise different components (d) and. In addition to water, also having other organic cosolvents can be a part of adhesive dispersion (I).

[0103] In a preferred embodiment, the adhesive dispersion (I) contains at least one component (e) selected from the group of polymer softeners and surfactant additives. Preferred polymer softeners are, for example, alkoxylated bisphenols, such as, in particular, alkoxylated bisphenol A, preferably ethoxylated bisphenol A. Preferred surfactant additives are polydimethylsiloxanes, such as, for example, polydimethylsiloxane-poly(ethylene oxide-co-propylene oxide)-copolymers. In a preferred embodiment, both of the aforementioned components (e) are contained in the adhesive dispersion (I).

[0104] As mentioned above, in one embodiment of the present invention, adhesive dispersion (I) contains at least one component (b). In principle, polyethyleneimine (b) can be added at any position and time of the preparation adhesive dispersion (I). As known, the production of adhesive dispersion containing polymer (a), water and also other components such as components (c) or (e) and organic solvents involves different steps of adding components in a separate order, thereby including one or more intermediate and / or final stirring and / or dispersion steps in the addition procedure. For example, polyethyleneimine (b) can be introduced as the first component or one of the first components. In addition, polyethyleneimine (b) can be added in an intermediate position before or after the intermediate dispersion step. Quite obviously, it can also be added in the final position, for example directly before or even after the final stirring / dispersion step. Preferably, polyethyleneimine (b) is added in a certain position before carrying out at least one other dispersion step.

[0105] Complete set packaging part

[0106] Another subject of the invention is a kit of parts for producing an aqueous cathodically depositable electrodeposition coating material composition comprising

[0107] (I) at least one binder dispersion comprising at least one cathodically depositable polymer (a), and

[0108] (II) at least one pigment paste comprising at least one pigment and / or filler,

[0109] The at least one alkoxylated polyethyleneimine (b) is part of the at least one binder dispersion (I) and / or part of the at least one pigment paste (II).

[0110] The kit of parts thus comprises at least two different parts, namely the binder dispersion (I) and the pigment paste (II). At least one of these separate parts comprises the polyethyleneimine (b).

[0111] The present invention also includes a method for producing a cathode-depositable electrodeposition coating material composition, comprising:

[0112] - providing (I) at least one binder dispersion comprising at least one cathodically depositable polymer (a)

[0113] - providing at least one pigment paste (II) comprising at least one pigment and / or filler,

[0114] wherein the binder dispersion (I) and / or the pigment paste (II) comprises at least one alkoxylated polyethyleneimine (b),

[0115] - Mixing the binder dispersion (I), the pigment paste (II) and any further potential components of the composition.

[0116] Quite obviously, any and all essential and also preferred features and embodiments mentioned above in the context of the composition of the invention apply equally to the kit parts and the method of manufacture.

[0117] Method for electrocoating

[0118] Another subject of the present invention is a method for at least partially coating an electrically conductive substrate by cathodic electrodeposition coating, the method comprising at least steps (1) to (5), namely

[0119] (1) at least partially immersing the conductive substrate in an electrodeposition coating bath containing the electrodeposition coating material composition of the present invention,

[0120] (2) connecting the substrate as a cathode,

[0121] (3) depositing a coating film obtained from the electrodeposition coating material composition on the substrate using direct current,

[0122] (4) removing the coated substrate from the electrodeposition coating bath, and

[0123] (5) Baking the coating film deposited on the substrate.

[0124] All preferred embodiments described hereinabove with respect to the electrodeposition coating material composition of the present invention are also preferred embodiments with respect to the above-described method of the present invention for at least partially coating a conductive substrate by cathodic electrodeposition coating using such an electrodeposition coating material composition.

[0125] Preferably, the above method comprises a step (4.1) of rinsing the coated substrate, for example with DI water, between steps (4) and (5). Quite obviously, this step serves to clean the substrate, ie to remove residual coating material that was not well deposited on the substrate.

[0126] The method of the present invention is particularly suitable for the electrodeposition coating of automobile bodies or parts thereof (comprising corresponding metal substrates). Therefore, preferred substrates are automobile bodies or parts thereof. Since the electrodeposition coating material composition of the present invention is particularly useful for obtaining excellent edge protection, as a preferred embodiment, metal substrates with quite a lot of such edges will be mentioned. In particular, such substrates are metal automobile component parts, such as transverse control arms, spring-loaded control arms or dampers. Such component parts can be cast iron parts or can also be produced by other established methods known in the art. In addition, such substrates are metal automobile bodies, such as partially stamped to cut out specific parts or form specific geometric shapes and therefore also include automobile bodies with quite a lot of edges. Therefore, in a preferred embodiment of the present invention, substrates are selected from the aforementioned substrates with many edges.

[0127] As also already described above, the significant edge protection achieved by the present invention is particularly useful in the context of metal substrates having edges that have at least partially not been post-treated like, for example, sanded or polished, which means that these edges remain quite sharp. Therefore, in another preferred embodiment of the present invention, the substrate is selected from the aforementioned substrates having edges that have at least partially not been post-treated like, for example, sanded or polished or otherwise treated to reduce the edge, furthermore, referred to as unsanded or unpolished.

[0128] Suitable as conductive substrates for use according to the invention are all conductive substrates commonly used and known to the skilled person. The conductive substrate used according to the invention is preferably a metal substrate, more preferably selected from the group consisting of steel, preferably steel selected from the group consisting of bare steel, cold rolled steel (CRS), hot rolled steel, galvanized steel (such as hot dip galvanized steel (HDG)), alloy galvanized steel (e.g. Galvalume, Galvannealed or Galfan) and aluminized steel, aluminum and magnesium, and also Zn / Mg alloys and Zn / Ni alloys. Particularly suitable substrates are parts for the production of car bodies or entire car bodies.

[0129] Before the corresponding electrically conductive substrate is used in step (1) of the method according to the invention, it is preferably cleaned and / or degreased.

[0130] The conductive substrate used according to the invention is preferably a pretreated substrate, for example with at least one metal phosphate such as zinc phosphate. This pretreatment by phosphating is usually carried out after the substrate has been cleaned and before the substrate is coated by electrodeposition in step (1), and is in particular a pretreatment step commonly used in the automotive industry. However, pretreatment methods other than phosphating are also possible, for example thin film pretreatment based on zirconium oxide or typical silanes.

[0131] During the steps (1), (2) and (3) of the method of the present invention, the electrodeposition coating material composition of the present invention is cathode deposited on the substrate area immersed in the bath in step (1). In step (2), the substrate is connected as a cathode, and a voltage is applied between the substrate and at least one counter electrode, which is located in the deposition bath or exists separately from it, for example, through an anion exchange membrane permeable to anions. Therefore, the counter electrode acts as an anode. When an electric current is passed between the anode and the cathode, a firmly adhered coating film is deposited on the cathode, that is, on the immersed part of the substrate. The voltage applied here is preferably in the range of from 50 to 500 volts. When the steps (1), (2) and (3) of the method of the present invention are carried out, the electrodeposition coating bath preferably has a bath temperature in the range of from 20° C. to 45° C.

[0132] The baking temperature in step (5) is preferably in the range of from 100°C to 210°C, more preferably from 120°C to 205°C, very preferably from 120°C to 200°C, more particularly from 125°C to 195°C or from 125°C to 190°C, most preferably from 130°C to 185°C or from 140°C to 180°C.

[0133] After carrying out step (5) of the method of the present invention, one or more additional coatings may be applied to the baked coating film obtained after step (5). For example, a primer and / or filler may be applied, followed by a basecoat and a clearcoat.

[0134] Therefore, the method of the present invention preferably comprises at least one further step (6), namely

[0135] (6) At least one additional coating material composition different from the composition applied in step (1) is at least partially applied to the baked coating film obtained after step (5).

[0136] Substrate

[0137] Another subject of the invention is an electrically conductive substrate at least partially coated with the baked electrodeposition coating material of the invention. The baked coating material corresponds to the baked coating film obtained after step (5) of the process of the invention.

[0138] All preferred embodiments described above with respect to the electrodeposition coating material composition of the invention and the method of the invention are also preferred embodiments with respect to the above-mentioned at least partially coated substrate of the invention.

[0139] Of course, the baked electrodeposition coating produced from the electrodeposition coating material composition of the present invention is also a subject of the present invention.

[0140] method

[0141] 1. Determination of the non-volatile fraction

[0142] The non-volatile fraction (solids or solids content) is determined according to DIN EN ISO 3251 (date: June 2019). This involves weighing 1 g of sample into an aluminum pan that has been dried beforehand, drying the pan with the sample at 180° C. in a drying cabinet for 30 minutes, cooling it in a desiccator and then reweighing. The residue corresponds to the non-volatile fraction (in % or wt.-%) relative to the total amount of sample used.

[0143] 2. VDA Climate Change Test (DIN EN ISO 11997-1:2018-01)

[0144] 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 10 or 20 so-called cycles.

[0145] If the coating to be tested is present on a metal substrate with holes, these holes simulate real metal substrates with a rather high number of edges / edge areas. Furthermore, in the case of substrates with holes, the edges of these holes have not been post-treated, like for example sanding or polishing before any pre-treatment and coating process begins, these substrates are even more challenging in terms of coating and therefore corrosion edge protection. The extent of corrosion on the edges of these holes (also called "hole edge corrosion" or "edge corrosion") can be visually assessed by observing the extent / portion of the hole edge that is corroded after the climate change test (rating scale from 1 to 5, where "5" means 100% corrosion (the entire edge of the hole is corroded) and "1" means 0% corrosion).

[0146] If the coating of the sample to be tested is scored to the substrate by knife cutting before the climate change test, the sample can be tested for the extent of subfilm corrosion in accordance with DIN EN ISO 4628-8 (03-2013), because during the climate change test the substrate corrodes along the score line. As the corrosion progresses, the coating is more or less penetrated during the test. The extent of the damage in [mm] is a measure of the corrosion resistance of the coating (also called score corrosion).

[0147] Each scoring result further shown below is the average of 3 to 5 individual test results. Each individual test result is produced by an individual plate (i.e., a coated test substrate), whereby each individual plate exhibits seven individual holes. Thus, an individual test result of an individual plate regarding hole edge protection is itself an average of the analysis of seven individual holes.

[0148] 3. Salt spray test

[0149] The corrosion resistance of the coating can also be determined by a salt spray test. The coated substrates under investigation were subjected to a salt spray test according to DIN EN ISO 9227 NSS (date: September 2012). The samples under investigation were housed in a chamber at a temperature of 35°C, continuously over a duration of 1008 hours or 2016 hours, with a mist generated by a 5% strength sodium chloride solution with a controlled pH in the range from 6.5 to 7.2. The mist was deposited on the samples under investigation and covered them with a film of corrosive salt water.

[0150] If the coating to be tested is present on a metal substrate with holes, these holes are similar to real metal substrates with a rather high number of edges / edge areas. Moreover, in the case of substrates with holes, the edges of these holes have not been sanded / polished before any pre-treatment and coating process begins, these substrates are similar to corresponding substrates with a large number of edges / edge areas that have not been sanded / polished and are therefore even more challenging in terms of coating and therefore corrosion edge protection. The extent of corrosion on the edges of these holes (also called "hole edge corrosion" or "edge corrosion") can be visually assessed by observing the extent / portion of the hole edge that is corroded after the climate change test (rating scale from 1 to 5, where "5" means 100% corrosion (the entire edge of the hole is corroded) and "1" means 0% corrosion).

[0151] If the coating on the sample under investigation is scored to the substrate with a razor blade cut before the salt spray test according to DIN EN ISO 9227 NSS, the level of corrosion damage of the sample can be investigated according to DIN EN ISO 4628-8 (03-2013), because during the DIN EN ISO 9227 NSS salt spray test, the substrate corrodes along the score line. As a result of the progressive course of corrosion, the coating is more or less destroyed during the test. The degree of damage in [mm] is a measure of the corrosion resistance of the coating (also called score corrosion).

[0152] Each scoring result further shown below is the average of 3 to 5 individual test results. Each individual test result is produced by an individual plate (i.e., a coated test substrate), whereby each individual plate exhibits seven individual holes. Thus, an individual test result of an individual plate regarding hole edge protection is itself an average of the analysis of seven individual holes.

[0153] 4. Surface roughness

[0154] The surface roughness was determined according to DIN EN 10049:2014-03. Quite obviously, lower values ​​[micrometers] reflect lower surface roughness and thus better coating smoothness and uniformity.

[0155] Each scoring result shown further below is an average of 3 to 5 individual test results. Each individual test result was produced from an individual panel (ie, coated test substrate).

[0156] Examples

[0157] The following examples further illustrate the present invention but should not be construed as limiting its scope.

[0158] 1. Preparation of aqueous cathode-depositable electrodeposition coating material composition

[0159] 1.1 Pigment paste (II)

[0160] The standard pigment paste P1 commonly used in the preparation of aqueous cathodically depositable electrodeposition coating material compositions is prepared by (i) mixing the corresponding ingredients in a dissolver and (ii) grinding the mixture from (i) using a standard mill under conventional conditions. Thus, all liquid ingredients are added in step (i) and then the solid components are introduced.

[0161] Pigment paste P1 contains an aqueous dispersion of an epoxy-amine adduct as grinding resin (component (a), solids content 40.4%). In addition, paste P1 contains bismuth (III) subsalicylate as catalyst, carbon black as black pigment, kaolin (ASP 200) as filler and also further components, in particular water and additives customary for aqueous cathodically depositable electrodeposition coating material compositions. The solids content of pigment paste P1 is 62.0%.

[0162] Furthermore, a pigment paste P2 was prepared. In principle, the preparation was carried out as for paste P1. However, as the last position of the liquid components, HP20 (BASF) (component (b), solids content 80%-82%) The effective amount of component (b) is 2 wt.-%, based on the total weight of the pigment paste P2.

[0163] HP20 (BASF) is a branched ethoxylated polyethyleneimine having a degree of ethoxylation of 28 and a number average molecular weight of 8600 g / mol (for the determination method, see the detailed description of the invention above).

[0164] 1.2 Adhesive dispersion (I)

[0165] As standard binder dispersion (I), the system B1 usually used in electrodeposition coating material compositions was used. The binder dispersion contains an aqueous dispersion of an epoxy-amine adduct as a binder resin (also component (a), but different from the epoxy-amine adduct used in the pigment paste), a blocked isocyanate as a crosslinking component (c) and also further ingredients, such as, in particular, conventional additives, organic cosolvents and water. The ingredients of the binder dispersion are added in a separate order, whereby different mixing (dissolving) steps and two dispersion stages occur. The solids content of the binder dispersion is 36% (binder dispersion B1).

[0166] Furthermore, adhesive dispersions B2 to B4 containing alkoxylated polyethyleneimines were produced. In principle, the preparation was carried out in accordance with dispersion B1. The deviations and differences were as follows:

[0167] Binder Dispersion B2: After preparing Binder Dispersion B1, add HP20 (BASF).

[0168] Binder Dispersion B3: In the production process of Binder Dispersion B1, the last component added before the first dispersion stage is the crosslinking component (c). In the preparation of Binder Dispersion B3, directly after the addition of the crosslinker (c) and before the start of the first dispersion stage, HP20 (BASF).

[0169] Binder dispersion B4: The preparation of binder dispersion B1 includes a second dispersion stage, whereby the dispersion speed of this step is higher than during the first dispersion stage. In the preparation of binder dispersion B4, HP20 (BASF).

[0170] The effective amount of component (b) in the binder dispersions B2-B4 is 2.0 wt.-%, based on the total weight of the corresponding binder dispersion.

[0171] 1.3 Electrodeposition coating material composition

[0172] By the above pigment paste and binder dispersion, an electrodeposition coating material composition was prepared. Although the comparative system was prepared by pigment paste P1 and binder dispersion B1 not containing component (b) (i.e. alkoxylated polyethyleneimine), the composition of the present invention contains component (b) in the pigment paste or binder dispersion.

[0173] Details of the corresponding baths and their components are shown in Table 1. The components listed in the table were mixed with one another in this order, thereby forming an electrodeposition coating material composition for application (item 2. below).

[0174] Table 1: Electrodeposition coating material composition

[0175]

[0176]

[0177] As can be observed above, the amount of component (b) in the composition (E-1) according to the invention is 2000 ppm, while in the compositions (E-2) to (E-4) according to the invention the amount is about 0.95 wt.-% (or 9500 ppm), in each case based on the total weight of the bath.

[0178] 2. Electrodeposition coating of substrate

[0179] The coating film obtained from the electrodeposition coating material composition described above under Item 1.3 was deposited on a cathodically connected test board 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 thickness of 20 μm.

[0180] As test panels, cold rolled steel substrates ( GB26S 6800 OC). Before pretreatment, the test plate was punched to produce seven individual holes. These holes and their edges were not sanded or polished, respectively, which means that they are similar to the corresponding unsanded / polished edges of the real substrate.

[0181] Table 2 shows the details of the cured coatings prepared on substrates according to study 3. below.

[0182] Table 2: Cured coatings on substrates

[0183] Cured coating on substrate Electrodeposition coating material composition SC C SE-1 E-1 SE-2 E-2 SE-3 E-3 SE-4 E-4

[0184] 3. Characterization of coated substrates

[0185] According to the above method, the corrosion resistance of the cured coating on the substrate is studied. More specifically, the coating on the substrate is studied with respect to some or all of the following properties:

[0186] -Hole edge corrosion (edge ​​corrosion), salt spray test 1008 hours (SST 1008)

[0187] -Edge corrosion, VDA climate change test 10 cycles (VDA 10)

[0188] - Scribe corrosion, SST 1008

[0189] -Surface roughness

[0190] Table 4 shows the corresponding data on the corrosion test

[0191]

[0192] The results show that the composition and cured coating of the present invention, respectively, show significantly enhanced edge corrosion protection. Similarly, the impact on scribe corrosion is negligible or at least not very high.

[0193] Furthermore, the results for the surface roughness of all investigated systems lie within a generally acceptable range between 0.5 and 1.0, which means that no relevant negative impact on the surface roughness is observed.

Claims

1. An aqueous cathode-depositable electrodeposition coating material composition comprising (I) at least one binder dispersion comprising at least one cathodically depositable polymer (a), and (II) at least one pigment paste comprising at least one pigment and / or filler, The preparation of the electrodeposition coating material composition comprises mixing the binder dispersion (I) and the pigment paste (II), and wherein the composition further comprises at least one alkoxylated polyethyleneimine (b), and The at least one alkoxylated polyethyleneimine (b) is part of the at least one binder dispersion (I) and / or part of the at least one pigment paste (II).

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

3. The coating material composition according to claim 1 or 2, characterized in that: The at least one alkoxylated polyethyleneimine (b) is an ethoxylated, propoxylated and / or mixed ethoxylated / propoxylated polyethyleneimine.

4. The coating material composition according to claim 3, characterized in that: The at least one alkoxylated polyethyleneimine (b) is an ethoxylated polyethyleneimine.

5. The coating material composition according to any one of the preceding claims, characterized in that The at least one alkoxylated polyethyleneimine (b) has a degree of alkoxylation (ie the average number of polymeric alkoxy moieties (ie O-alkyl-moieties) per alkoxylation-modified amino group) of from 10 to 100.

6. The coating material composition according to any one of the preceding claims, characterized in that The at least one alkoxylated polyethyleneimine (b) has a number average molecular weight of 2500 to 30000 g / mol.

7. The coating material composition according to any one of the preceding claims, characterized in that The component (b) is contained in the composition in an amount ranging from 0.01 to 10 wt.-%, based on the total weight of the electrodeposition material coating composition.

8. The coating material composition according to any one of the preceding claims, characterized in that At least one epoxide-amine adduct is present as at least one polymer (a).

9. The coating material composition according to any one of the preceding claims, characterized in that As at least one polymer (a), at least one epoxide-amine adduct is present, which is the reaction product of at least one epoxy resin based on bisphenol A with at least one primary and / or secondary amine and / or salt thereof and / or at least one tertiary amine or salt thereof.

10. The coating material composition according to any one of the preceding claims, characterized in that It contains (c) at least one crosslinker component.

11. The coating material composition according to claim 10, characterized in that: At least one blocked polyisocyanate is present as at least one crosslinker component (c).

12. A kit of parts for making an aqueous cathode-depositable electrodeposition coating material composition, comprising (I) at least one binder dispersion comprising at least one cathodically depositable polymer (a), and (II) at least one pigment paste comprising at least one pigment and / or filler, The at least one alkoxylated polyethyleneimine (b) is part of the at least one binder dispersion (I) and / or part of the at least one pigment paste (II).

13. A method for producing a cathode-depositable electrodeposition coating material composition, comprising: - providing at least one binder dispersion (I) comprising at least one cathodically depositable 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.

14. A method for at least partially coating a conductive substrate by cathodic electrodeposition coating, the method comprising at least steps (1) to (5), namely (1) at least partially immersing the conductive substrate in an electrodeposition coating bath comprising the electrodeposition coating material composition according to any one of claims 1 to 11, (2) connecting the substrate as a cathode, (3) depositing a coating film obtained from the electrodeposition coating material composition on the substrate using direct current, (4) removing the coated substrate from the electrodeposition coating bath, and (5) Baking the coating film deposited on the substrate.

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

16. An electrically conductive substrate at least partially coated with an electrodeposition coating material composition in baked form according to any one of claims 1 to 11 and / or produced according to claim 12 and / or obtainable by a process according to claim 13 or 14.

17. Use of at least one alkoxylated polyethyleneimine as defined in any one of claims 1 to 6 for improving the edge corrosion protection of an electrically conductive substrate with a baked coating film obtained from an aqueous cathodically depositable electrodeposition coating material composition comprising - in addition to the at least one alkoxylated polyethyleneimine - at least one cathodically depositable polymer (a).

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