EP1192226B1 - Electrodeposition bath with water-soluble polyvinyl alcohol (co)polymers - Google Patents

Abstract

The invention relates to the use of a water-soluble polyvinyl alcohol (co)polymer or a mixture of polyvinyl alcohol (co)polymers as additives in aqueous electrodeposition baths, to electrodeposition baths comprising a polyvinyl alcohol (co)polymer, and to a method of coating an electrically conductive substrate.

Description

The invention relates to a new use of water-soluble Polyvinyl alcohol (co) polymers, containing a polyvinyl alcohol (co) polymer Electrocoating bath and a process for the production of coated Substrates using the electrodeposition bath.

Electrocoating is a well-known method of coating the surface of electrically conductive objects (compare for example: Glasurit manual paints and paints, Curt R. Vincentz Verlag, Hanover, 1984, Pages 374 to 384 and pages 457 to 462, as well as DE-A-35 18 732, DE-A-35 18 770, EP-A-0 040 090, EP-A-0 012 463, EP-A-0 259 181, EP-A-0 433 783 and EP-A-0 262 069). The process is used to coat objects made of metal, especially for priming automobile bodies, or for Coating of conductive plastic used.

The paints used in electrodeposition coating generally contain synthetic resins containing amino groups or carboxyl groups as binders, the neutralization of the amino or carboxyl groups achieving water dispersibility. Special grinding resins and optionally other non-water-dispersible constituents such as polymers, plasticizers, pigments, fillers, additives and auxiliaries can be further constituents of the electrodeposition paints. The crosslinking agents used in the electrodeposition paints are either not water-dispersible or can be water-dispersible, the electrodeposition paints being externally crosslinking, or also self-crosslinking or curable with condensation.
By modifying the binding agent, selecting the crosslinking agent and varying the composition of the constituents of the electrodeposition paint, the properties of the paint, such as corrosion protection, adhesion and flow, are influenced. In particular, electrodeposition paints are known in which the addition of polymer microparticles or suspended or dispersed polymer powders is intended to favorably influence the protection against corrosion, especially on edges.

For example, EP-A-0 259 181 recommends that the edges of the coated substrate be closed observed increased susceptibility to corrosion due to an inadequate to fix thick lacquer layer by adding polymer microgels, e.g. Poly (meth) acrylate copolymers in combination with ethylenically unsaturated Vinyl compounds can be part of such microgels.

Subsequently addable microgel dispersions based on epoxy-amine adducts are characterized by their good tolerance and high efficacy as Edge protection additives from, as described in EP 0626 000.

In DE-B-26 50 611, EP-A-0 052 831, DE-A-39 40 782, EP-A-0 433 783, SU-A-436890, JP-A-53094346, JP-A-79028410 and JP-A-0624820 are used Electrocoating agents with suspendable or dispersible Plastic powders described, which are predominantly free from ionic groups, may melt during stoving, are uncrosslinked or crosslinked, the coating agents additionally being those typical for electrocoating contain water-dispersible synthetic resins. The particle sizes of such Plastic powder can significantly reduce the particle sizes of the water-dispersible synthetic resins of known electrodeposition paints exceed: the average particle diameter in JP-A-0624820 is 1 to 50 Micrometers, in DE-A-39 40 782 and EP-A-0 433 783 at 0.1 to 100 Micrometer.

The addition of those in EP-A-0 259 181, DE-B-26 50 611, EP-A-0 052 831, EP-A-0 433 783, SU-A-436890, JP-A-53094346, JP-A-79028410 and JP-A-0624820 polymer particles described leads to aqueous electrodeposition paints in some Cases to improve the edge coverage. In contrast, the corrosion protection of the deposited electrocoat films, especially at the edges, despite the Improved edge coverage inadequate.

Disadvantageous side effects of adding plastic powder are one Deterioration of the wrap around the electrocoat, the adhesion to the substrate and / or to subsequent coatings, such as overcoated paint layers or PVC underbody protection, deterioration in mechanical properties, such as Flexibility, ductility, breaking and impact resistance, poorer flow properties and a drastic deterioration in the course.

Another major disadvantage of the patent specifications EP-A-0 259 181, DE-B-26 50 611, EP-A-0 052 831, EP-A-0 433 783, SU-A-436890, JP-A-53094346, JP-A-79028410, JP-A-0624820, SU-A-661637, SU-A-998592 and SU-A-310952 aqueous and non-aqueous formulations described is the deficient one Stability of paints that tend to sediment. It can be in aqueous Electrodeposition paints for massive coverage of the ultrafiltration membrane with coarse plastic particles come.

The stability disadvantages of the paints are eliminated by incorporating copolymers with vinyl acetal, vinyl alcohol and ethylene units directly into the resins, for example. by grafting reaction, as described in DE 196 18 379.
The proportion is more than 10% by weight. of polymer resin is necessary to achieve adequate edge coverage.
The incorporation of plastic powder or microgels requires proportions in the percentage range, whereby the flow is in some cases drastically impaired.

Much more effective, even at low concentrations such as 500 ppm, im Electrodeposition paints are water-soluble cellulose ethers, such as hydroxyethyl cellulose, (EP 0640 700). The effectiveness is not permanent, however, because of the degradation of the polymer takes place.

Polyvinyl alcohols are widely used in paints, especially as Suspension stabilizers in the polymerization of vinyl monomers. During the Use of polyvinyl alcohols as complexing agents and suspension stabilizers in the pre-treatment of iron, steel, zinc and aluminum sheets in combination with chromates or fluorine compounds is known (J 73008702, WO 9627034), in particular the electrophoretic deposition of metal suspensions, such as Aluminum (SU 738334, J-A-111201), metal oxide suspensions, such as bsw. Chrome-, Aluminum, titanium and zirconium oxide (J-A-111201, SU 493817), metal salt suspensions, such as lead, zinc or copper salts (SU 436890, SU 511392, SU 054452, WO 9208168), as well as direct deposition of metals such as lead (SU 321265), direct use in electrodeposition paints is limited to one subsequent treatment of the deposited film by contact with a aqueous polyvinyl alcohol solution and subsequent stoving. Through this subsequent treatment creates a matting effect (JP 56044799) or Surface defects such as craters are reduced (DE 4303787).

In contrast, the invention is based on the technical problem, a Electrocoating indicate which coatings result in all requirements in terms of edge protection and resistance to contamination, especially towards Oiling is sufficient and at the same time can be produced with little effort and has long-term stability are.

To solve this technical problem, the invention teaches the use of a water soluble polyvinyl alcohol (co) polymers or a mixture of Polyvinyl alcohol (co) polymers as an additive in aqueous electrocoating baths.

Aqueous electrocoating baths contain little or no organic Solvent.

The term water soluble means a real dissolution process in water and not a dispersion of particulate units at the supermolecular level. The polyvinyl alcohol (co) polymer is preferably used as an additive in aqueous solution prepared, if necessary with conventional paint additives, and the aqueous solution dem Electrocoating bath added. The term "additive" defines that the Polyvinyl alcohol (co) polymer as a molecularly independent unit in Electrocoating bath is present and in particular not reactive in a binder, resin or the like is involved. Of course, this definition does not conclude from that the polyvinyl alcohol (co) polymer is reactive in a deposited coating is incorporated into the other components of the deposited coating.

In the context of the present invention, the term polyvinyl alcohol (co) polymer denotes a random copolymer or block copolymer which contains polymer units of the general formula I, or a homopolymer which consists of polymer units of the general formula I, the polyvinyl alcohol copolymers being advantageous according to the invention, and therefore are preferred. - [- C (R ¹ ) ₂ -C (R ¹ ) (OH) -] - (I)

In the polyvinyl alcohol (co) polymers to be used according to the invention the polymer building blocks I be linked head-to-head or head-to-tail. The polymer building blocks I are advantageously to a far predominant extent Head and tail linked.

In the general formula I, the variable R ^{1 stands} for hydrogen atoms or for substituted or unsubstituted alkyl, cycloalkyl, alkylcycloalkyl, cycloalkylalkyl, aryl, alkylaryl, cycloalkylaryl, arylalkyl or arylcycloalkyl radicals.

Examples of suitable alkyl radicals are methyl, ethyl, propyl, isopropyl, n-butyl, iso-butyl, tert-butyl, amyl, hexyl or 2-ethylhexyl.

Examples of suitable cycloalkyl radicals are cyclobutyl, cyclopentyl or cyclohexyl.

Examples of suitable alkylcycloalkyl radicals are methylenecyclohexane, Ethylene cyclohexane or propane-1,3-diyl-cyclohexane.

Examples of suitable cycloalkylalkyl radicals are 2-, 3- or 4-methyl-, -ethyl-, - Propyl- or -butylcyclohex-1-yl.

Examples of suitable aryl radicals are phenyl, naphthyl or biphenylyl.

Examples of suitable alkylaryl radicals are benzyl, ethylene or propane-1,3-diylbenzene.

Examples of suitable cycloalkylaryl radicals are 2-, 3- or 4-phenylcyclohex-1-yl.

Examples of suitable arylalkyl radicals are 2-, 3- or 4-methyl-, -ethyl-, -propyl- or -Butylphen-1-yl.

Examples of suitable arylcycloalkyl radicals are 2-, 3- or 4-cyclohexylphen-1-yl.

The radicals R ¹ described above can be substituted. For this purpose, electron-withdrawing or electron-donating atoms or organic radicals can be used.

Examples of suitable substitutes are halogen atoms, especially chlorine and Fluorine, nitrile groups, nitro groups, partially or fully halogenated, in particular chlorinated and / or fluorinated, alkyl, cycloalkyl, alkylcycloalkyl, Cycloalkylalkyl, aryl, alkylaryl, cycloalkylaryl, arylalkyl and Arylcycloalkyl radicals, including those mentioned above by way of example, in particular tert-butyl; Aryloxy, alkyloxy and cycloalkyloxy radicals, in particular phenoxy, Naphthoxy, methoxy, ethoxy, propxy, butyloxy or cyclohexyloxy; Arylthio, Alkylthio and cycloalkylthio radicals, in particular phenylthio, naphthylthio, Methylthio, ethylthio, propylthio, butylthio or cyclohexylthio; Hydroxyl groups; and / or primary, secondary and / or tertiary amino groups, especially amino, N-methylamino, N-ethylamino, N-propylamino, N-phenylamino, N-cyclohexylamino, N, N-dimethylamino, N, N-diethylamino, N, N-dipropylamino, N, N-diphenylamino, N, N-dicyclohexylamino, N-cyclohexyl-N-methylamino or N-ethyl-N-methylamino.

According to the invention, it is advantageous if the radicals R ^{1 are} predominantly hydrogen atoms, that is to say that the other radicals R ^{1 are} only present in a minor proportion. In the context of the present inventions, the term “subordinate portion” denotes a portion which advantageously varies the application properties profile of the polyvinyl alcohol (co) polymers, in particular their water solubility, and does not deteriorate or even completely change them. Special advantages result if they change the radicals R ^{1 are} exclusively hydrogen atoms, that is to say that the polymer building blocks I are derived from the hypothetical polyvinyl alcohol. Accordingly, polyvinyl alcohol (co) polymers which contain these polymer building blocks I are used with particular preference.

In addition to the polymer building blocks I, the polyvinyl alcohol copolymers to be used according to the invention also contain, in particular, polymer building blocks of the general formula II. - [- C (R ¹ ) ₂ -C (R ¹ ) (OC (O) R ² ) -] - (II)

In the general formula II, the radicals R ^{1 have} the meaning given above, hydrogen atoms also being of particular advantage here and therefore being used with particular preference. The radicals R ² represent alkyl radicals with one to ten carbon atoms, preferably methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, tert-butyl, amyl, hexyl or 2-ethylhexyl, particularly preferably methyl. Accordingly, the particularly preferred polymer building blocks II are derived from vinyl acetate. Here, the polymer building blocks II can be linked head-to-head or head-to-tail. Advantageously, the polymer building blocks II are by far predominantly head-to-tail linked.

• im wesentlichen säuregruppenfreien (Meth)acrylsäureester,
• Monomere, welche mindestens eine Hydroxylgruppe pro Molekül tragen und im wesentlichen säuregruppenfrei sind, wie Hydroxyalkylester der Acrylsäure, Methacrylsäure oder einer anderen alpha,beta-olefinisch ungesättigten Carbonsäure, die sich von einem Alkylenglykol ableiten, das mit der Säure verestert ist, oder die durch Umsetzung der alpha,beta-olefinsich ungesättigten Carbonsäure mit einem Alkylenoxid erhältlich sind,
• Monomere, welche mindestens eine Säuregruppe, die in die entsprechende Säureaniongruppe überführbar ist, pro Molekül tragen,
• Vinylester von in alpha-Stellung verzweigten Monocarbonsäuren mit 5 bis 18 Kohlenstoffatomen im Molekül,
• Umsetzungsprodukte aus Acrylsäure und/oder Methacrylsäure mit dem Glycidylester einer in alpha-Stellung verzweigten Monocarbonsäure mit 5 bis 18 C-Atomen je Molekül,
• cyclische und/oder acyclische Olefine wie Ethylen, Propylen, But-1-en, Pent-1-en, Hex-1-en, Cyclohexen, Cyclopenten, Norbonen, Butadien, Isopren, Cylopentadien und/oder Dicyclopentadien, insbesondere Ethylen,
• (Meth)Acrylsäureamide
• Epoxidgruppen enthaltende Monomere wie die Glycidylester ethylenisch ungesättigter Carbonsäuren,
• vinylaromatische Kohlenwasserstoffe,
• Nitrile,
• Vinylverbindungen, insbesondere Vinyl- und/oder Vinylidendihalogenide, N-Vinylpyrrolidon oder Vinylether,
• Allylverbindungen, insbesondere Allylether und -ester.

In addition, the polyvinyl alcohol copolymers can also contain other customary and known ethylenically unsaturated monomers such as

• essentially acid group-free (meth) acrylic acid esters,
• Monomers which carry at least one hydroxyl group per molecule and are essentially free of acid groups, such as hydroxyalkyl esters of acrylic acid, methacrylic acid or another alpha, beta-olefinically unsaturated carboxylic acid, which are derived from an alkylene glycol which is esterified with the acid, or which are obtained by reaction the alpha, beta-olefin unsaturated carboxylic acid can be obtained with an alkylene oxide,
• Monomers which carry at least one acid group per molecule that can be converted into the corresponding acid anion group,
• Vinyl esters of alpha-branched monocarboxylic acids with 5 to 18 carbon atoms in the molecule,
• Reaction products of acrylic acid and / or methacrylic acid with the glycidyl ester of a monocarboxylic acid branched in the alpha position and having 5 to 18 carbon atoms per molecule,
• cyclic and / or acyclic olefins such as ethylene, propylene, 1-butene, 1-pentene, 1-hexene, cyclohexene, cyclopentene, norbonene, butadiene, isoprene, cyclopentadiene and / or dicyclopentadiene, in particular ethylene,
• (Meth) acrylic acid amides
• Monomers containing epoxy groups such as the glycidyl esters of ethylenically unsaturated carboxylic acids,
• vinyl aromatic hydrocarbons,
• Nitriles,
• Vinyl compounds, in particular vinyl and / or vinylidene dihalides, N-vinylpyrrolidone or vinyl ethers,
• Allyl compounds, especially allyl ethers and esters.

If these monomers are also used, they are to be used according to the invention using polyvinyl alcohol copolymers only in a minor proportion included, this term also here in the sense explained above is applied. Of these monomers, the acyclic olefins offer in particular ethylene and propylene, in particular ethylene, particular advantages and are therefore preferably used if necessary.

Advantageously, those to be used according to the invention have Polyvinyl alcohol (co) polymers have a degree of polymerization of 100 to 20,000, preferably 200 to 15,000, particularly preferably 300 to 12,000 and in particular 400 up to 10,000.

The content of polymer building blocks I is advantageously in the Polyvinyl alcohol copolymers at 50 to 99.9, preferably 60 to 99.9, especially preferably 70 to 99 and in particular 80 to 99 mol%.

In the context of the present invention, the polyvinyl alcohol copolymers offer the particularly advantageous polymer building blocks I and II contain very special ones Advantages and are therefore used very particularly preferably according to the invention. These polyvinyl alcohol copolymers are also known in the art for short Called polyvinyl alcohols.

It is known that the polyvinyl alcohols are not by direct Polymerization processes are accessible, but are based on polymer analogs Reactions produced by hydrolysis of polyvinyl acetate. Particularly advantageous Commercial polyvinyl alcohols have molecular weights of 10,000 to 500,000 Daltons, preferably 15,000 to 320,000 Daltons and especially 20,000 to 300,000 daltons. Very particularly advantageous, commercially available polyvinyl alcohols have a degree of hydrolysis of 98 to 99 or 87 to 89 mol%.

The vinyl alcohol content can be determined, for example, indirectly via the DIN ester number 53401 determine, namely by the remaining proportion of vinyl acetate after the Hydrolysis is determined by means of the ester number.

The water solubility of these polyvinyl alcohols can be reduced by the subsequent polymer-analogous modification with aldehydes varies within a wide range will. It is known that cyclic acetals are formed in this reaction. Examples of suitable acetalized polyvinyl alcohols are from patent DE-A-196 18 379 known.

Surprisingly, with the addition of the easy to manufacture and easy to use Way as an additive to the electrodeposition paint bath Polyvinyl alcohol (co) polymers, especially polyvinyl alcohols, all Edge protection that meets requirements and a very good one Contamination resistance, especially against oil, achieved. The same is true of the course outstanding. It has also been shown that only very small amounts of Polyvinyl alcohol (co) polymer are required as an additive, which also leads to a considerable cost advantage compared to the additives that improve the edge protection from the state of the art.

In the context of the invention, it is advantageous if the proportion of Polyvinyl alcohol (co) polymers, especially polyvinyl alcohols, in the Electrocoating bath 2 to 10,000 ppm, preferably 20 to 5,000 ppm, each based on the total weight of the electrocoating bath. If that Electrocoating bath pigments (inorganic) in a proportion of more than 10%, based on the solids of the electrodeposition bath, then usually suffices Addition in an amount of 2 to 3,000, in particular 300 to 1,500 ppm.

The use according to the invention is within the scope of all customary anodic (ATL) or cathodic (KTL) electrodeposition paint baths (ETL) are advantageous.

These electrodeposition baths are aqueous coating materials (ETL) with a Solids content of in particular 5 to 30% by weight.

(A) üblichen und bekannten Bindemitteln, die ionische oder in ionische Gruppen überführbare funktionelle Gruppen (a1) sowie zur chemischen Vernetzung befähigte funktionelle Gruppen (a2) tragen, wobei sie fremd- und/oder selbstvernetzend, insbesondere aber fremdvernetzend, sind;

(B) gegebenenfalls Vernetzungsmitteln, die komplementäre funktionelle Gruppen (b1) tragen, die mit den funktionellen Gruppen (a2) chemische Vernetzungsreaktionen eingehen können, und dann obligatorisch angewandt werden, wenn die Bindemittel (A) fremdvernetzend sind;

(C) übliche und bekannte Lackadditive sowie

(D) die vorstehend im Detail beschriebenen erfindungsgemäß zu verwendenden Polyvinylalkohol(co)polymeren, insbesondere Polyvinylalkohole.

The solid of the ETL according to the invention consists of

(A) customary and known binders which carry ionic functional groups (a1) or functional groups which can be converted into ionic groups and functional groups (a2) capable of chemical crosslinking, whereby they are externally and / or self-crosslinking, but in particular externally crosslinking;

(B) optionally crosslinking agents which carry complementary functional groups (b1) which can enter into chemical crosslinking reactions with the functional groups (a2) and which are then used obligatorily if the binders (A) are externally crosslinking;

(C) customary and known paint additives as well

(D) the polyvinyl alcohol (co) polymers to be used according to the invention, in particular polyvinyl alcohols, described in detail above.

Are the crosslinking agents (B) and / or their functional groups (b1) ready in the binder (A) incorporated, one speaks of self-crosslinking.

The binders (A) come as complementary functional groups (a2) preferably thio, amino, hydroxyl, carbamate, allophanate, carboxy, and / or (meth) acrylate groups, but in particular hydroxyl groups, and as complementary functional groups (b1) preferably anhydride, carboxy, Epoxy, blocked isocyanate, urethane, methylol, methylol ether, siloxane, amino, Hydroxy and / or beta-hydroxyalkylamide groups, but especially blocked Isocyanate groups into consideration.

(a11) funktionelle Gruppen, die durch Neutralisationsmittel und/oder Quaternisierungsmittel in Kationen überführt werden können, und/oder kationische Gruppen
oder

(a12) funktionelle Gruppen, die durch Neutralisationsmittel in Anionen überführt werden können, und/oder anionische Gruppen.

Examples of suitable ionic functional groups (a1) of the binders (A) which can be converted into ionic groups are

(a11) functional groups which can be converted into cations by neutralizing agents and / or quaternizing agents, and / or cationic groups
or

(a12) functional groups which can be converted into anions by neutralizing agents and / or anionic groups.

The binders (A) with functional groups (a11) are in cathodic separable electrodeposition paints (KTL) are used, whereas the binders (A) with functional groups (a12) used in anodic electrodeposition paints (ATL) will.

Examples of suitable functional groups (a11) to be used according to the invention, those by neutralizing agents and / or quaternizing agents in cations are primary, secondary or tertiary amino groups, secondary sulfide groups or tertiary phosphine groups, especially tertiary ones Amino groups or secondary sulfide groups.

Examples of suitable cationic groups to be used according to the invention (a11) are primary, secondary, tertiary or tertiary sulfonium groups or quaternary Phosphonium groups, preferably quaternary ammonium groups or quaternary Ammonium groups, tertiary sulfonium groups, but especially quaternary groups Ammonium groups.

Examples of suitable functional groups (a12) to be used according to the invention, which can be converted into anions by neutralizing agents Carboxylic acid, sulfonic acid or phosphonic acid groups, in particular Carboxylic acid groups.

Examples of suitable anionic groups to be used according to the invention (a12) are carboxylate, sulfonate or phosphonate groups, in particular Carboxylate groups.

The selection of the groups (a11) or (a12) is to be made so that no disturbing Reactions with the functional groups (a2) with the crosslinking agents (B) can react, are possible. The person skilled in the art can therefore make the selection in a simpler manner Wise, based on their expertise.

Examples of suitable neutralizing agents for functional ones convertible to cations Groups (a11) are inorganic and organic acids such as sulfuric acid, Hydrochloric acid, phosphoric acid, formic acid, acetic acid, lactic acid, Dimethylolpropionic acid or citric acid, especially formic acid, acetic acid or lactic acid.

Examples of suitable neutralizing agents for convertible into anions functional groups (a12) are ammonia, ammonium salts such as, for example

Ammonium carbonate or ammonium hydrogen carbonate, as well as amines, e.g. Trimethylamine, triethylamine, tributylamine, dimethylaniline, diethylaniline, Triphenylamine, dimethylethanolamine, diethylethanolamine, methyldiethanolamine, Triethanolamine and the like.

In general, the amount of neutralizing agent is chosen so that 1 to 100 equivalents, preferably 50 to 90 equivalents of the functional Groups (a11) or (a12) of the binder (b1) are neutralized.

Examples of suitable binders (A) for ATL are from patent DE-A-2824 418 known. These are preferably polyester, epoxy resin ester, Poly (meth) acrylates, maleic oils or polybutadiene oils with a weight average Molecular weight from 300 to 10,000 Daltons and an acid number from 35 to 300 mg KOH / g.

Examples of suitable KTL can be found in the patents EP-A-0 082 291, EP-A-0 234 395, EP-A-0 227 975, EP-A-0 178 531, EP-A-333 327, EP-A-0 310 971, EP-A-0 456 270, US-A-3,922,253, EP-A-0 261 385, EP-A-0 245 786, DE-A-33 24 211, EP-A-0 414 199 or EP-A-476 514 known. These are preferably primary, secondary, tertiary or quaternary amino or ammonium groups and / or resins (A) containing tertiary sulfonium groups and having amine numbers preferably between 20 and 250 mg KOH / g and a weight average Molecular weight from 300 to 10,000 daltons. In particular, be Amino (meth) acrylate resins, amino epoxy resins, amino epoxy resins with terminal Double bonds, aminoepoxy resins with primary and / or secondary Hydroxyl groups, amino polyurethane resins, amino group-containing polybutadiene resins or modified epoxy-carbon dioxide-amine reaction products.

According to the invention, KTL and the corresponding electrodeposition baths preferably used.

The EDL preferably contain crosslinking agents (B).

Examples of suitable crosslinking agents (B) are blocked organic ones Polyisocyanates, in particular blocked so-called paint polyisocyanates, with aliphatically, cycloaliphatically, araliphatically and / or aromatically bound, blocked isocyanate groups.

Polyisocyanates with 2 to 5 isocyanate groups are preferred for their preparation per molecule and with viscosities from 100 to 10,000, preferably 100 to 5000 and in particular 100 to 2000 mPas (at 23 ° C) are used. In addition, the Polyisocyanates in the customary and known manner are hydrophilic or hydrophobic be modified.

Examples of suitable polyisocyanates are, for example, in "Methods of organic chemistry ", Houben-Weyl, Volume 14/2, 4th edition, Georg Thieme Verlag, Stuttgart 1963, pages 61 to 70, and by W. Siefken, Liebigs Annalen der Chemie, Volume 562, pages 75 to 136. For example, the Polyurethane prepolymers containing isocyanate groups, which are produced by the reaction of polyols can be prepared with an excess of polyisocyanates and the are preferably of low viscosity.

Further examples of suitable polyisocyanates are isocyanurate, biuret, allophanate, Iminooxadiazinedione, urethane, urea and / or uretdione groups Polyisocyanates. Polyisocyanates containing urethane groups are, for example by reacting part of the isocyanate groups with polyols, e.g. Trimethylolpropane and glycerol, obtained, are preferably aliphatic or cycloaliphatic polyisocyanates, especially hexamethylene diisocyanate, dimerized and trimerized hexamethylene diisocyanate, isophorone diisocyanate, 2-isocyanatopropylcyclohexyl isocyanate, Dicyclohexylmethane-2,4'-diisocyanate, Dicyclohexylmethane-4,4'-diisocyanate or 1,3-bis (isocyanatomethyl) cyclohexane (BIC), diisocyanates derived from dimer fatty acids such as those under the The trade name DDI 1410 is sold by the Henkel company, 1,8-diisocyanato-4-isocyanatomethyl octane, 1,7-diisocyanato-4-isocyanatomethylheptane or 1-isocyanato-2- (3-isocyanatopropyl) cyclohexane or mixtures of these polyisocyanates are used.

i) Phenole wie Phenol, Cresol, Xylenol, Nitrophenol, Chlorophenol, Ethylphenol, t-Butylphenol, Hydroxybenzoesäure, Ester dieser Säure oder 2,5- di-tert.-Butyl-4-hydroxytoluol;

ii) Lactame, wie ε-Caprolactam, δ-Valerolactam, γ-Butyrolactam oder β-Propiolactam;

iii) aktive methylenische Verbindungen, wie Diethylmalonat, Dimethylmalonat, Acetessigsäureethyl- oder -methylester oder Acetylaceton;

iv) Alkohole wie Methanol, Ethanol, n-Propanol, Isopropanol, n-Butanol, Isobutanol, t-Butanol, n-Amylalkohol, t-Amylalkohol, Laurylalkohol, Ethylenglykolmonomethylether, Ethylenglykolmonoethylether, Ethylenglykolmonobutylether, Diethylenglykolmonomethylether, Diethylenglykolmonoethylether, Propylenglykolmonomethylether, Methoxymethanol, Glykolsäure, Glykolsäureester, Milchsäure, Milchsäureester, Methylolharnstoff, Methylolmelamin, Diacetonalkohol, Ethylenchlorohydrin, Ethylenbromhydrin, 1,3-Dichloro-2-propanol, 1,4-Cyclohexyldimethanol oder Acetocyanhydrin;

v) Mercaptane wie Butylmercaptan, Hexylmercaptan, t-Butylmercaptan, t-Dodecylmercaptan, 2-Mercaptobenzothiazol, Thiophenol, Methylthiophenol oder Ethylthiophenol;

vi) Säureamide wie Acetoanilid, Acetoanisidinamid, Acrylamid, Methacrylamid, Essigsäureamid, Stearinsäureamid oder Benzamid;

vii) Imide wie Succinimid, Phthalimid oder Maleimid;

viii) Amine wie Diphenylamin, Phenylnaphthylamin, Xylidin, N-Phenylxylidin, Carbazol, Anilin, Naphthylamin, Butylamin, Dibutylamin oder Butylphenylamin;

ix) Imidazole wie Imidazol oder 2-Ethylimidazol;

x) Harnstoffe wie Harnstoff, Thioharnstoff, Ethylenharnstoff, Ethylenthioharnstoff oder 1,3-Diphenylharnstoff;

xi) Carbamate wie N-Phenylcarbamidsäurephenylester oder 2-Oxazolidon;

xii) Imine wie Ethylenimin;

xiii) Oxime wie Acetonoxim, Formaldoxim, Acetaldoxim, Acetoxim, Methylethylketoxim, Düsobutylketoxim, Diacetylmonoxim, Benzophenonoxim oder Chlorohexanonoxime;

xiv) Salze der schwefeligen Säure wie Natriumbisulfit oder Kaliumbisulfit;

xv) Hydroxamsäureester wie Benzylmethacrylohydroxamat (BMH) oder Allylmethacrylohydroxamat; oder

xvi) substituierte Pyrazole, Ketoxime, Imidazole oder Triazole; sowie

Examples of suitable blocking agents for preparing the blocked polyisocyanates (B) are the blocking agents known from US Pat. No. 4,444,954, such as

i) Phenols such as phenol, cresol, xylenol, nitrophenol, chlorophenol, ethylphenol, t-butylphenol, hydroxybenzoic acid, esters of this acid or 2,5-di-tert-butyl-4-hydroxytoluene;

ii) lactams, such as ε-caprolactam, δ-valerolactam, γ-butyrolactam or β-propiolactam;

iii) active methylenic compounds such as diethyl malonate, dimethyl malonate, ethyl or methyl acetoacetate or acetylacetone;

iv) alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, t-butanol, n-amyl alcohol, t-amyl alcohol, lauryl alcohol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol ether, methyl glycol monomethyl ether, diethylene glycol ether, methyl glycol monomethyl ether, diethylene glycol monobutyl ether, diethylene glycol ether, glycol monomethyl ether, Glycolic acid esters, lactic acid, lactic acid esters, methylol urea, methylol melamine, diacetone alcohol, ethylene chlorohydrin, ethylene bromohydrin, 1,3-dichloro-2-propanol, 1,4-cyclohexyldimethanol or acetocyanhydrin;

v) mercaptans such as butyl mercaptan, hexyl mercaptan, t-butyl mercaptan, t-dodecyl mercaptan, 2-mercaptobenzothiazole, thiophenol, methylthiophenol or ethylthiophenol;

vi) Acid amides such as acetoanilide, acetoanisidinamide, acrylamide, methacrylamide, acetic acid amide, stearic acid amide or benzamide;

vii) imides such as succinimide, phthalimide or maleimide;

viii) amines such as diphenylamine, phenylnaphthylamine, xylidine, N-phenylxylidine, carbazole, aniline, naphthylamine, butylamine, dibutylamine or butylphenylamine;

ix) imidazoles such as imidazole or 2-ethylimidazole;

x) ureas such as urea, thiourea, ethylene urea, ethylene thiourea or 1,3-diphenylurea;

xi) carbamates such as phenyl N-phenylcarbamate or 2-oxazolidone;

xii) imines such as ethyleneimine;

xiii) oximes such as acetone oxime, formaldoxime, acetaldoxime, acetoxime, methyl ethyl ketoxime, diisobutyl ketoxime, diacetyl monoxime, benzophenone oxime or chlorohexanone oxime;

xiv) salts of sulphurous acid such as sodium bisulfite or potassium bisulfite;

xv) hydroxamic acid esters such as benzyl methacrylohydroxamate (BMH) or allyl methacrylohydroxamate; or

xvi) substituted pyrazoles, ketoximes, imidazoles or triazoles; as

Mixtures of these blocking agents, especially dimethylpyrazole and triazoles, Malonic esters and acetoacetic acid esters, dimethylpyrazole and succinimide or Butyl diglycol and trimethylol propane.

Further examples of suitable crosslinking agents (B) are all known aliphatic and / or cycloaliphatic and / or aromatic polyepoxides, for example based on bisphenol-A or bisphenol-F. Suitable as polyepoxides are, for example, also those commercially available under the names Epikote® der Shell, Denacol® from Nagase Chemicals Ltd., Japan Polyepoxides, such as Denacol EX-411 (pentaerythritol polyglycidyl ether), Denacol EX-321 (trimethylolpropane polyglycidyl ether), Denacol EX-512 (polyglycerol polyglycidyl ether) and Denacol EX-521 (polyglycerol polyglycidyl ether).

eingesetzt werden.Tris (alkoxycarbonylamino) triazines (TACT) of the general formula can also be used as crosslinking agents (B)

can be used.

Examples of suitable tris (alkoxycarbonylamino) triazines (B) are in the US-A-4,939,213, US-A-5,084,541 or EP-A-0 624 577 are described. In particular, the tris (methoxy, tris (butoxy and / or tris (2-ethylhexoxycarbonylamino) triazines) used.

The methyl-butyl mixed esters and the butyl-2-ethylhexyl mixed esters are advantageous and the butyl esters. These have the advantage over the pure methyl ester better solubility in polymer melts and also less prone to Crystallize.

Further examples of suitable crosslinking agents (B) are amino resins, for example melamine, guanamine, benzoguanamine or urea resins. Included The customary and known amino resins are also suitable, their Methylol and / or methoxymethyl groups e.g. T. by means of carbamate or Allophanate groups are defunctionalized. Crosslinking agents of this type are used in US-A-4 710 542 and EP-B-0 245 700 and in the article by B. Singh et al. "Carbamylmethylated Melamines, Novel Crosslinkers for the Coatings Industry "in Advanced Organic Coatings Science and Technology Series, 1991, Volume 13, pages 193-207.

Further examples of suitable crosslinking agents (B) are beta-hydroxyalkylamides such as N, N, N ', N'-tetrakis (2-hydroxyethyl) adipamide or N, N, N', N'-tetrakis (2-hydroxypropyl) adipamide.

Further examples of suitable crosslinking agents (B) are compounds with on average at least two groups capable of transesterification, for example Reaction products of malonic acid diesters and polyisocyanates or of esters and partial esters of polyhydric alcohols of malonic acid with monoisocyanates, such as them European Patent EP-A-0 596 460;

The amount of crosslinking agents (B) in the coating material of the invention or ETL can vary widely and is based in particular on the one hand Functionality of the crosslinking agent (B) and on the other hand according to the number of im Binder (A) existing crosslinking functional groups (a2) and after the network density that you want to achieve. The skilled person can therefore determine the amount the crosslinking agent (B) on the basis of his general technical knowledge, if appropriate determine with the help of simple, orienting experiments. Advantageously is the crosslinking agent (B) in the coating material of the invention in one Amount of 5 to 60% by weight, particularly preferably 10 to 50% by weight and in particular 15 to 45 wt .-%, each based on the solids content of the coating material according to the invention contain. It is recommended to use the further to choose the amounts of crosslinking agent (B) and binder (A) so that in the coating material of the invention the ratio of functional Groups (b1) in the crosslinking agent (B) and functional groups (a2) in Binder (A) between 2: 1 to 1: 2, preferably 1.5: 1 to 1: 1.5, especially preferably 1.2: 1 to 1: 1.2 and in particular 1.1: 1 to 1: 1.1.

• organische und/oder anorganische Pigmente, Korrosionsschutzpigmente und/oder Füllstoffe wie Calciumsulfat, Bariumsulfat, Silikate wie Talk oder Kaolin, Kieselsäuren, Oxide wie Aluminiumhydroxid oder Magnesiumhydroxid, Nanopartikel, organische Füllstoffe wie Textilfasern, Cellulosefasern, Polyethylenfasern oder Holzmehl, Titandioxid, Ruß, Eisenoxid, Zinkphosphat oder Bleisilikat; diese Additive können auch über Pigmentpasten in die erfindungsgemäße ETL eingearbeitet werden, wobei als Reibharze die vorstehend beschriebenen Bindemittel (A) in Betracht kommen;
• Radikalfänger;
• organische Korrosionsinhibitoren;
• Katalysatoren für die Vernetzung wie anorganische und organische Salze und Komplexe des Zinns, Bleis, Antimons, Wismuts, Eisens oder Mangans, vorzugsweise organische Salze und Komplexe des Wismuts und des Zinns, insbesondere Wismutlactat, -ethylhexanoat oder -dimethylolpropionat, Dibutylzinnoxid oder Dibutylzinndilaurat;
• Slipadditive;
• Polymerisationsinhibitoren;
• Entschäumer;
• Emulgatoren, insbesondere nicht ionische Emulgatoren wie alkoxylierte Alkanole und Polyole, Phenole und Alkylphenole oder anionische Emulgatoren wie Alkalisalze oder Ammoniumsalze von Alkancarbonsäuren, Alkansulfonsäuren, und Sulfosäuren von alkoxylierten Alkanolen und Polyolen, Phenolen und Alkylphenole;
• Netzmittel wie Siloxane, fluorhaltige Verbindungen, Carbonsäurehalbester, Phosphorsäureester, Polyacrylsäuren und deren Copolymere oder Polurethane;
• Haftvermittler;
• Verlaufmittel;
• filmbildende Hilfsmittel wie Cellulose-Derivate;
• Flammschutzmittel;
• organische Lösemittel;
• niedermolekulare, oligomere und hochmolekulare Reaktivverdünner, die an der thermischen Vernetzung teilnehmen können, insbesondere Polyole wie Tricyclodecandimethanol, dendrimere Polyole, hyperverzweigte Polyester, Polyole auf der Basis von Metatheseoligomeren oder verzweigten Alkanen mit mehr als acht Kohlenstoffatomen im Molekül;
• Antikratermittel;

The coating material or EDL according to the invention can contain customary lacquer additives (C) in effective amounts. Examples of suitable additives (C) are

• organic and / or inorganic pigments, anti-corrosive pigments and / or fillers such as calcium sulfate, barium sulfate, silicates such as talc or kaolin, silicic acids, oxides such as aluminum hydroxide or magnesium hydroxide, nanoparticles, organic fillers such as textile fibers, cellulose fibers, polyethylene fibers or wood flour, titanium dioxide, carbon black, iron oxide, Zinc phosphate or lead silicate; these additives can also be incorporated into the EDL according to the invention via pigment pastes, the binders (A) described above being suitable as grinding resins;
• Radical scavengers;
• organic corrosion inhibitors;
• Catalysts for crosslinking such as inorganic and organic salts and complexes of tin, lead, antimony, bismuth, iron or manganese, preferably organic salts and complexes of bismuth and tin, in particular bismuth lactate, ethylhexanoate or dimethylol propionate, dibutyltin oxide or dibutyltin dilaurate;
• Slip additives;
• Polymerization inhibitors;
• Defoamer;
• Emulsifiers, in particular non-ionic emulsifiers such as alkoxylated alkanols and polyols, phenols and alkylphenols or anionic emulsifiers such as alkali salts or ammonium salts of alkanecarboxylic acids, alkanesulphonic acids, and sulphonic acids of alkoxylated alkanols and polyols, phenols and alkylphenols;
• Wetting agents such as siloxanes, fluorine-containing compounds, carboxylic acid half-esters, phosphoric acid esters, polyacrylic acids and their copolymers or polyurethanes;
• Adhesion promoter;
• Leveling agent;
• film-forming auxiliaries such as cellulose derivatives;
• Flame retardants;
• organic solvents;
• low molecular weight, oligomeric and high molecular weight reactive diluents which can take part in thermal crosslinking, in particular polyols such as tricyclodecane dimethanol, dendrimeric polyols, hyperbranched polyesters, polyols based on metathesis oligomers or branched alkanes with more than eight carbon atoms in the molecule;
• Anti-crater agents;

Further examples of suitable paint additives are given in the textbook "Paint additives" described by Johan Bieleman, Wiley-VCH, Weinheim, New York, 1998.

The invention finally teaches a method for painting electrically conductive Substrates in which (1) the electrically conductive substrate in an electrodeposition bath is immersed as described above, (2) the substrate as a cathode or anode, preferably as a cathode, is switched on, (3) by direct current Film is deposited on the substrate, (4) the painted substrate from the Electrodeposition paint bath is removed, (5) the deposited paint film is baked and, (6) optionally, following step (5) a filler, a stone chip protection paint and a solid top coat or, alternatively, a base coat and a clear coat are applied and are baked, the basecoat and the clearcoat preferably after Wet-on-wet process can be applied and baked.

Examples 1. Preparation of the crosslinking agent (B) 1.1 Preparation of the crosslinking agent (B1)

In a reactor equipped with a stirrer, reflux condenser, internal thermometer and Inert gas inlet is equipped, 10552 parts are isomers and higher-functional Oligomers based on 4,4'-diphenylmethane diisocyanate with an NCO equivalent weight of 135 g / eq (Lupranat®, BASF / Germany; NCO functionality approx. 2.7; Content of 2,2'- and 2,4'-diphenylmethane diisocyanate below 5%) presented under nitrogen atmosphere. 18 parts of dibutyltin dilaurate are added and drops 9498 parts of butyl diglycol at such a rate that the Product temperature remains below 60 ° C. If necessary, it must be cooled. To At the end of the addition, the temperature is kept at 60 ° C. for a further 60 minutes and is reduced NCO equivalent weight of 1120 g / eq determined (based on solids). To Dissolving in 7768 parts of methyl isobutyl ketone, 933 parts are melted Trimethylolpropane added at such a rate that a Product temperature of 100 ° C is not exceeded. After the end of the addition one leaves react for a further 60 min. There are no NCO groups in the subsequent control more verifiable. It is cooled to 65 ° C. and diluted at the same time 965 parts of n-butanol and 267 parts of methyl isobutyl ketone.

The solids content is 70.1% (1 h at 130 ° C.).

1.2 Preparation of the crosslinking agent (B2)

In a reactor equipped with a stirrer, reflux condenser, internal thermometer and Inert gas inlet is equipped, 12,208 parts are isomers and higher-functional Oligomers based on 4,4'-diphenylmethane diisocyanate with an NCO equivalent weight of 135 g / eq (Lupranat®, BASF / Germany; NCO functionality approx. 2.7; 2,2'- and 2,4'-diphenylmethane diisocyanate content below 5%) submitted under a nitrogen atmosphere. 8 parts of dibutyltin dilaurate are added and drops 10499 parts of butyl diglycol at such a rate that the Product temperature remains below 60 ° C. It may have to be cooled. To At the end of the addition, the temperature is kept at 60 ° C. for a further 60 minutes and is reduced NCO equivalent weight of 887 g / eq determined (based on solids). To Dissolving in 4500 parts of methyl isobutyl ketone, 1293 parts are melted Trimethylolpropane added at such a rate that a Product temperature of 100 ° C is not exceeded. After the end of the addition one leaves react for a further 60 min. There are no NCO groups in the subsequent control more verifiable. It is cooled to 65 ° C. and diluted at the same time 599 parts of n-butanol and 893 parts of methyl isobutyl ketone.

The solids content is 80.5% (1 h at 130 ° C).

2. Production of the preliminary product (solution of diethylenetriamine-diketimine in methyl isobutyl ketone)

From a 70 weight percent solution of diethylenetriamine in Methyl isobutyl ketone is removed azeotropically from the water of reaction at 110-140 ° C. It is then diluted with methyl isobutyl ketone until the solution is a Has amine equivalent weight of 127.

3. Production of aqueous dispersions, the cathodically depositable resins (A) and a crosslinking agent (B) 3.1 Preparation of the aqueous binder dispersion (A / B1)

In a reactor equipped with a stirrer, reflux condenser, internal thermometer and Inert gas inlet is equipped, 6150 parts of epoxy resin are based on Bisphenol A with an epoxy equivalent weight (EEW) of 188 along with 1400 parts of bisphenol A, 335 parts of dodecylphenol, 470 parts of p-cresol and 441 parts Parts of xylene heated to 125 ° C. under a nitrogen atmosphere and stirred for 10 min. The mixture is then heated to 130 ° C. and 23 parts of N, N-dimethylbenzylamine are added. The reaction mixture is held at this temperature until the EEW has reached a value of 880 g / eq.

A mixture of 7097 parts of the crosslinking agent (B) and 90 parts of the additive K2000 (polyether, Byk Chemie / Germany) is then added and the mixture is kept at 100.degree.
Half an hour later, 211 parts of butyl glycol and 1210 parts of isobutanol are added.

Immediately thereafter is a mixture of 467 parts of the intermediate according to. 2. (Diethylenetriamine diketimine in methyl isobutyl ketone) and 520 parts Methylethanolamine and added to the reactor and the batch to 100 ° C tempered. After a further half an hour, the temperature is increased to 105 ° C and adds 159 parts of N, N-dimethylaminopropylamine.

75 minutes after the addition of the amine, 903 parts of Plastilit® 3060 are used (Propylene glycol compound, BASF / Germany), diluted with 522 parts Propylene glycol phenyl ether (mixture of 1-phenoxy-2-propanol and 2-phenoxy-1-propanol, BASF / Germany), and at the same time cools down rapidly to 95 ° C. After 10 minutes, 14821 parts of the reaction mixture are placed in a dispersing vessel convicted. There, 474 parts of lactic acid (88% in Water), dissolved in 7061 parts of deionized water. Then 20 min homogenized before using a further 12600 parts of deionized water in small Portions being further diluted.

The volatile solvents are removed by distillation in vacuo and then replaced in the same amount by deionized water.

The dispersion (A / B1) has the following key figures: Solids content 33.8% (1 hour at 130 ° C) 29.9% (1/2 hour at 180 ° C) Base content 0.71 milliequivalents / g solid (130 ° C) Acidity 0.36 milliequivalents / g solid (130 ° C) pH 6.3 Particle size 116 nm (Mass mean from photon correlation spectroscopy)

3.2 Preparation of the aqueous binder dispersion (A / B2)

The binder dispersion (A / B2) is produced in a completely analogous manner to Binder dispersion (A / B1), however, are used immediately after dilution with Propylene glycol phenyl ether 378 parts of K-KAT® XP 348 (bismuth 2-ethylhexanoate; 25% bismuth, King Industries, USA) with stirring in the organic stage mixed in. After cooling, completely analogous to (A / B1) 14821 parts of the Reaction mixture dispersed:

The dispersion (A / B2) has the following key figures: Solids content 33.9% (1 hour at 130 ° C) 30.1% (1/2 hour at 180 ° C) Base content 0.74 milliequivalents / g solid (130 ° C) Acidity 0.48 milliequivalents / g solid (130 ° C) pH 5.9 Particle size 189 nm (Mass mean from photon correlation spectroscopy)

3.3 Preparation of the aqueous binder dispersion (A / B3)

In a reactor equipped with a stirrer, reflux condenser, internal thermometer and Inert gas inlet is equipped, 6824 parts are based on epoxy resin Bisphenol A with an epoxy equivalent weight (EEW) of 188 along with 1984 parts of bisphenol A, 2527 parts of ethoxylated bisphenol A with an OH number of 222 (Dianol® 265, Akzo / Netherlands) and 597 parts of methyl isobutyl ketone heated to 130 ° C. under a nitrogen atmosphere. Then 16 parts of N, N-dimethylbenzylamine added, heated to 150 ° C and about 30 min at a Maintained temperature between 150 and 190 ° C. Then it is raised to 140 ° C cooled down. Then 21 parts of N, N-dimethylbenzylamine are added and the temperature held until the EEW has reached a value of 1120 g / eq.

10113 parts of the crosslinking agent (B2) are then added and the temperature is reduced to 100.degree. A mixture of 634 parts of the precursor (diethylenetriamine-diketimine in methyl isobutyl ketone; see point 2) and 597 parts of methylethanolamine is then added to the reactor and the reaction mixture is kept at 115 ° C. for one hour until a viscosity of approx dPa.s is reached (50% solution in methoxypropanol, cone / plate viscometer at 23 ° C). 648 parts of propylene glycol phenyl ether (mixture of 1-phenoxy-2-propanol and 2-phenoxy-1-propanol, from BASF / Germany) are then added.
After 10 minutes, the entire reaction mixture is transferred to a dispersing vessel. There, 609 parts of lactic acid (88% in water) and 152 parts of emulsifier mixture (mixture of 1 part butyl glycol and 1 part of a tertiary acetylene glycol (Surfynol 104, Air Products / USA)), dissolved in 30266 parts of deionized, are added in portions with stirring Water, too.

The volatile solvents are removed by distillation in vacuo and then replaced in the same amount by deionized water.

The dispersion (A / B3) has the following key figures: Solids content 37.0% (1 hour at 130 ° C) 34.1% (1/2 hour at 180 ° C) Base content 0.53 milliequivalents / g solid (130 ° C) Acidity 0.32 milliequivalents / g solid (130 ° C) pH 6.6 Particle size 150 nm (Mass mean from photon correlation spectroscopy)

4. Production of aqueous solutions of polyvinyl alcohol (co) polymers (D) 4.1 Preparation of an aqueous solution of poly (vinyl alcohol-co-vinyl acetate) (D1)

Poly (vinyl alcohol-co-vinyl acetate): Mowiol® 47-88, Clariant / Germany Weight average molar mass 228,000 daltons Polyvinyl alcohol content 89.2% Polyvinyl acetate content 10.8%

In a reactor equipped with a stirrer, reflux condenser, internal thermometer and inert gas inlet, 28491 parts of deionized water are placed at room temperature. 1500 parts of poly (vinyl alcohol-co-vinyl acetate) as fine granules are continuously stirred into the initially charged water and then heated to 80 ° C. with stirring.
After reaching 80 ° C., the mixture is kept stirring for two hours, the polymer being completely dissolved. This is followed by cooling to 35 ° C.

The viscous solution is stabilized against bacterial attack with 9 parts of Parmetol® K40 (Schülke and Mayr / Germany).
The solids content of the solution is 5.0% (1 h at 130 ° C.).

4.2 Preparation of an aqueous solution of poly (vinyl alcohol-covinylacetate-co-ethylene) (D2)

Poly (vinyl acetate-co-ethylene): Laboratory product, BASF AG, Germany Weight average molar mass 239,000 daltons Polyvinyl acetate content 92.8% Polyethylene content 7.2%

In a reactor equipped with a stirrer, reflux condenser, internal thermometer is equipped, 1000 ml of a 1% methanolic sodium hydroxide solution are heated to 50.degree warmed up. While stirring, a solution of Poly (ethylene-co-vinyl acetate) in methanol (300 g in 2000 ml of methanol) was added dropwise. When the addition is complete, the reaction is allowed to continue for 30 minutes and the is isolated deposited precipitate, washed alkali-free with methanol and dried in vacuo at approx. 40 ° C.

The product formed was characterized: Poly (vinyl alcohol-co-vinyl acetate-co-ethylene): Weight average molar mass 215,000 daltons Polyvinyl alcohol content 83.3% Polyvinyl acetate content 9.5% Polyethylene content 7.2%

Analogous to the procedure in point 4.1, an aqueous solution of poly (vinyl alcohol-co-vinyl acetate-co-ethylene manufactured.

The solids content of the solution is 5.0% (1 h at 130 ° C.).

5. Production of the pigment pastes 5.1 Production of the gray pigment paste (P1) 5.1.1 Preparation of a grinding resin solution with tertiary ammonium groups

According to EP 0 505 445 B1, example 1.3, an organic-aqueous grinding resin solution is used prepared by placing 2598 Parts of bisphenol A diglycidyl ether (epoxy equivalent weight (EEW) 188 g / eq), 787 Parts of bisphenol-A, 603 parts of dodecylphenol and 206 parts of butylglycol in Presence of 4 parts triphenylphosphine at 130 □ C up to an EEW of 865 g / eq can react. During cooling, 849 parts of butyl glycol and 1534 parts of D.E.R.® 732 (polypropylene glycol diglycidyl ether, DOW Chemikal, USA) and diluted at 90 ° C with 266 parts of 2,2'-aminoethoxyethanol and 212 Parts of N, N-dimethylaminopropylamine reacted further. After 2 hours it is Viscosity of the resin solution constant (5.3 dPa.s; 40% in Solvenon® PM (Methoxypropanol, BASF / Germany); Plate-cone viscometer at 23 ° C). It is diluted with 1512 parts of butyl glycol and the base groups are partially neutralized 201 parts of glacial acetic acid, further diluted with 1228 parts of deionized water and carries the end.

This gives a 60% aqueous-organic resin solution, its 10% Dilution has a pH of 6.0.

The resin solution is used directly for paste production.

5.1.2 Preparation of the pigment paste

To this end, 1897 parts of water and 1750 parts of the above resin solution described premixed. Now 21 parts Disperbyk® 110 (Fa. Byk-Chemie GmbH / Germany), 14 parts Lanco Wax® PE W 1555 (Langer & Co. / Germany), 42 parts carbon black, 420 parts aluminum hydro-silicate ASP 200 (Fa. Langer & Co. / Germany), 2667 parts of titanium dioxide TI-PURE® R 900 (DuPont, USA) and 189 parts of di-n-butyltin oxide were added. The mixture is left for 30 minutes predispersed under a high-speed dissolver stirrer. Then will the mixture in a small laboratory mill (Motor Mini Mill, Eiger Engineering Ltd., Great Britain) for 1 to 1.5 hours up to a Hegmann fineness of less than / equal to 12 µm dispersed and adjusted to solids with more water.

A pigment paste PI which is stable to segregation is obtained. Solids content 60.0% (1/2 hour at 180 ° C)

5.2 Production of the gray pigment paste (P2) 5.2.1 Preparation of a grinding resin solution with sulfonium groups

An organic-aqueous sulfonium grating resin solution is prepared by in the first stage in a stainless steel reaction vessel 2632 parts of bisphenol A diglycidyl ether (Epoxy equivalent weight (EEW) 188 g / eq), 985 parts bisphenol-A, 95 parts of nonylphenol in the presence of 1 part of triphenylphosphine at 130 ° C to reacts to an EEW of 760 g / eq. During the cooling process, 996 Share 2-butoxypropanol, the temperature is lowered to 80 ° C.

Then 603 parts of thiodiethanol (50% in water) are added and 15 min stirred. After adding 661 parts of dimethylolpropionic acid and 152 parts The acid number is determined in deionized water.

The reaction is complete when the acid number is less than 5 (mg KOH per g Solid). Then 10541 parts of deionized water are gradually added.

This gives a 28% aqueous-organic resin solution (solids at 130 ° C, 60min: 28.0%).

The resin solution is used directly for paste production.

5.2.2 Preparation of a grinding resin solution with quaternary ammonium groups

First, 2040 parts of dimethylethanolamine are mixed with 7507 parts of 2-ethylhexanol-mono-urethane in a reactor of the toluene diisocyanate (90%) added so that the Temperature does not exceed 70 ° C. Then it is partially dissolved with 2199 parts of butyl glycol and 2751 parts of lactic acid (88%) and 2170 parts of deionized water admitted. The temperature rises to 90 ° C. After 3 hours it will Reaction product, which subsequently serves as quaternization reagent, drained.

It is an organic-aqueous grinding resin solution with quaternary Ammonium groups produced by being in the first stage in one Stainless steel reaction vessel 3512 parts bisphenol A diglycidyl ether (epoxy equivalent weight (EEW) 188 g / eq), 1365 parts bisphenol-A, 128 parts xylene 130 ° C in the presence of 4 parts of triphenylphosphine up to an EEW of 740 g / eq can react. The temperature is raised to 180 ° C. during the reaction increased. It is cooled and 1947 parts of 2-ethylhexanol-monourethane are obtained at 125.degree of the toluene diisocyanate (90%) was added. The temperature is approx. 2 Held for hours until isocyanate groups are no longer detectable by IR. To Dissolving with 4893 parts of butyl glycol, a temperature of 75 ° C is set and 3198 parts of the quaternizing reagent described above were added.

If the acid number is less than 1 (mg KOH per g of solid), it is 1457 parts Butyl glycol dissolved.

A 56% strength resin solution is obtained in this way (solids at 130 ° C., 60 min: 56.0%).

The resin solution is used directly for paste production.

5.2.3 Preparation of the pigment paste

To this end, 1863 parts of water and 4119 parts of the above described grinding resin solution with sulfonium groups (point 5.2.1) and 422 parts of Above grating resin solution with quaternary ammonium groups (point 5.2.2) premixed. 728 parts of aluminum hydro-silicate ASP 200 (Langer & Co. / Germany), 185 parts of carbon black, 6142 parts of titanium dioxide TI-PURE® R 900 (Fa. DuPont, USA) and 3639 parts of di-n-butyltin oxide were added. The mixture turns 30 Predispersed for min under a high-speed dissolver stirrer. The mixture is then in a small laboratory mill (Motor Mini Mill, Fa. Eiger Engineering Ltd., Great Britain) for 1 to 1.5 hours up to a Hegmann fineness of less than / equal to 12 µm dispersed and with more water Solid body set.

A pigment paste (P2) which is stable to segregation is obtained. Solids content 61.5% (1/2 hour at 180 ° C)

6. Production of electrodeposition paints according to the invention (ETL)

The proportions of the components in the electrodeposition baths are shown in Tables 1, 2 and 3 listed. Pigment-free and pigmented electrodeposition baths result (ETL).

These electrodeposition paints consist of mixtures of an aqueous dispersion (A / B) and deionized water. The resulting mixtures are added to the pigment paste (P) added with stirring in designated cases.

The aqueous solutions of polyvinyl alcohol (co) polymers (D) can be incorporated by adding to the binder dispersion (A / B) or pigment paste (P) with stirring, or by subsequent addition to the binder-paste mixture, as in the present case. Gray pigmented electrodeposition paints based on the binder dispersion (A / B1) and the pigment paste (P1) Electrodeposition paint Comparative experiment V1 example 1 Example 2 Polyvinyl alcohol (co) polymer 0 ppm 600 ppm 600 ppm Parts by weight (parts) Binder disp. (A / B1) 491 491 491 Pigment paste (P1) 120 120 120 Deion. water 389 377 377 Solution of the polyvinyl alcohol (co) polym. (D1) 12th (D2) 12th TOTAL 1000 1000 1000 Unpigmented electrocoat (clear lacquer) based on the binder dispersion (A / B2) Electrodeposition paint Comparative experiment V2 Example 3 Example 4 Polyvinyl alcohol (co) polymer 0 ppm 1500 ppm 600 ppm Parts by weight (parts) Binder disp. (A / B2) 498 498 498 Deion. water 502 462 462 Solution of the polyvinyl alcohol (co) polym. (D1) 40 (D2) 40 TOTAL 1000 1000 1000 Gray pigmented electrodeposition paints based on the binder dispersion (A / B3) and the pigment paste (P2) Electrodeposition paint Comparative experiment V3 Example 5 Example 6 Polyvinyl alcohol copolymer 0 ppm 600 ppm 600 ppm Parts by weight (parts) Binder disp. (A / B3) 416 416 416 Pigment paste (P2) 105 105 105 Deion. water 479 467 467 Solution of the polyvinyl alcohol (co) polym. (D1) 12th (D2) 12th TOTAL 1000 1000 1000

7. Deposition of electrodeposition paints according to the invention

After 5 days of aging at room temperature, a cathodic connection is made Steel test panel deposited with 150 ohm series resistor.

For this purpose, water-rinsed, zinc-phosphated steel test panels from Chemetall 3) (Bo26 W OC) was used. The deposition time is 2 minutes for one Bath temperature of 32 ° C. The deposition voltage was chosen so that a The result is a layer thickness of approx. 20 µm of the stoved paint film.

The deposited paint film is rinsed off with deionized water and 20 min Baked in for a long time at 180 ° C. The baked paint films thus obtained were checked.

The test results can be found in Tables 4 and 5.

7.1 Result of the depositions

Cathodically depositable electrodeposition paint baths without Additions of polyvinyl alcohol (co) polymers deposited (see also point 6., tab. 1-3).

The specified layer thicknesses are to be understood as dry film thicknesses. Test results of electrocoating baths based on the binder dispersions (A / B1) and (A / b2) with and without pigment paste (P1) Electrocoating baths Pigmented gray Unpigmented (clear coat) Examples (see Point 6; Tab. 1 and 2) V1 1 2 V2 3 4th Binder dispersion (A / B1) dito dito (STARTING AT 2)*) dito dito Pigment paste (P1) dito dito - - - PVAl-CP solution (1) - (D1) (D2) - (D1) (D2) Go PVAI copolymes. in bath (2), ppm 0 600 600 0 2000 2000 Deposition on zinc phosphate. Steel tested. (3) Layer thickness, µm 20.7 20.9 20.2 20.6 19.2 19.3 Voltage, V 300 310 300 320 320 320 Electrical figure of merit (4) as a measure of the edge coverage,% 6th 100 97 8th 88 73 History (5) 2 3 3 2 2 3 Corrosion protection after 10 Cycles climate change test (6) Infiltration at the scratch, mm (7) 2.3 2.1 2.1 2.3 2.1 2.3 Surface grate (8) 1 1 1 1 1 1 Edge grate (9) 3 1 1 4th 1 2 Corrosion protection according to the edge coating test of the Ford test method BI 127-01 (10) Number of rust points on a blade sheath (10) > 80 19th 21st > 80 29 35 Oil splash compatibility (11) according to BASF test method MEB0123A Cratered area per total area: in% (11) > 80 ≤10 ≤10 > 80 ≤10 ≤10 Test results of electrocoating baths based on the binder dispersion (A / B3) with pigment paste (P2) Electrocoating baths Pigmented gray Examples (see point 6; table 3) V3 5 6th Binder dispersion (FROM 3) dito dito Pigment paste (P2) dito dito PVAI-CP solution - (D1) (D2) Content of PVA1-Copolym. in the bathroom in ppm 0 600 600 Deposition on zinc-phosphated steel test panels Layer thickness in µm 20.2 19.9 20.3 Voltage in V 310 310 310 Electrical figure of merit as a measure of the edge coverage in% 12th 99 95 course 2 3 3 Corrosion protection after 10 cycles of alternating climatic tests Infiltration at the scratch in mm 2.6 2.4 2.4 Surface grate 1 1 1 Edge rust 3 1 1 Corrosion protection according to the edge coating test of the Ford test method BI 127-01 Number of rust spots on a blade sheath > 80 22nd 24 Oil splash compatibility according to BASF test method MEB0123A cratered area per total area in% > 80 ≤10 ≤10

Claims (7)

1. Use of a water-soluble polyvinyl alcohol (co)polymer or of a mixture of polyvinyl alcohol (co)polymers as an additive in aqueous cathodic electrodeposition baths, the fraction of polyvinyl alcohol (co)polymer in the electrodeposition bath being from 20 to 10 000 ppm, based on the total weight of the electrodeposition bath.
2. Use according to Claim 1, the polyvinyl alcohol (co)polymer being a copolymer of vinyl alcohol and ethylenically unsaturated monomers, preferably one ethylenically unsaturated monomer or two or more ethylenically unsaturated monomers, especially vinyl acetate, vinyl acetal, ethylene and/or propylene.
3. Use according to Claim 1 or 2, the polyvinyl alcohol (co)polymer having has a vinyl alcohol fraction of from 50 to 99.9, preferably from 60 to 99.9, with particular preference from 70 to 99, and in particular from 80 to 99 mol%.
4. Use according to one of Claims 1 to 3, the weight average molecular mass of the polyvinyl alcohol (co)polymer being from 10 000 to 500 000, preferably from 15 000 to 320 000, and in particular from 20 000 to 300 000 daltons.
5. Use according to one of Claims 1 to 4, the fraction of polyvinyl alcohol (co)polymer in the electrodeposition bath being from 20 to 5000 ppm, and in particular from 300 to 1500 ppm, based in each case on the total weight of the electrodeposition bath.
6. Aqueous cathodic electrodeposition bath comprising

   (A) a cathodically depositable binder,

   (B) optionally a crosslinking agent,

   (C) optionally, customary coatings additives, and

   (D) a dissolved polyvinyl alcohol (co)polymer according to one of Claims 2 to 5, the fraction of polyvinyl alcohol (co)polymer in the electrodeposition bath being from 20 to 10 000 ppm, based on the total weight of the electrodeposition bath.
7. Method of coating electrically conductive substrates, in which

   (1) the electrically conductive substrate is dipped into an electrodeposition bath according to Claim 6,

   (2) the substrate is connected as the cathode,

   (3) a film is deposited on the substrate by means of direct current,

   (4) the coated substrate is removed from the electrodeposition bath,

   (5) the deposited coating film is baked, and,

   (6) optionally, following step (5), a primer-surfacer, and/or a stonechip protectant material and a solid-color topcoat material, or alternatively a basecoat material and a clearcoat material, are applied and baked, the basecoat material and the clearcoat material being applied and baked in particular by the wet-on-wet technique.