DE3918784A1 - CATIONIC ELECTROPHORETIC COATINGS AND COATING METHODS USING THESE MASSES - Google Patents

Abstract

The invention provides (a) a cationic electrophoretic coating composition comprising: (i) a water-soluble to water-dispersible resin containing primary or secondary hydroxyl, tertiary amino and an isocyanate adduct residue having alpha , beta -unsaturated carbonyl and (ii) at least one specified curing catalyst; or (b) a cationic electrophoretic coating composition comprising a water-soluble to water-dispersible resin containing an isocyanate adduct residue having alpha , beta -unsaturated carbonyl, primary or secondary hydroxyl and at least one onium organic acid salt selected from among quaternary ammonium, quaternary phosphonium and tertiary sulfonium organic acid salts. In alternative embodiments, the hydroxyl groups and isocyanate adduct residues may be present in separate resins in composition (a) or (b), with the tertiary amino or onium groups being incorporated in either or both of the resins.

Description

The invention relates to cationic electrophoretic coating compositions and a method of electrophoretic Coating of objects with the masses, with the objects be used as a cathode.

Cationic electrophoretic coating materials are used in strong scope as primers for motor vehicles, single layer final coatings for industrial machines and devices and the like. Used. Fall under it such compositions that form a urethane bond are curable and predominantly for the above Application purposes are used. However, these masses have the disadvantage that the cured coating turns yellow or that it in the formation of a topcoat on the out of the mass prepared coating to penetrate the yellowing comes in the topcoat. In addition to that lately requirements for higher corrosion resistance of the coatings and on an improved Appearance of the coating, it is desirable to provide electrophoretic coating compositions which are suitable for forming thick coatings while Mas  Urethane bond type coatings give rise to in their Thickness limited to about 50 microns, as these masses at Harden large amounts of alcohol and the like. Release. Indeed the masses of the aforesaid type have the disadvantage that the coatings when applied in larger thicknesses irregularities on the surface, z. B. flaking and Shrinkage, yield and not fully harden and do not lead to the expected properties.

Furthermore, electrophoretic coating compositions are also available, belonging to the polybutadiene type, or one with an unsaturated fatty acid or similar compound contain modified resin and the case of oxidation or thermal polymerization without release of by-products cure. But even these masses have disadvantages. They lead not to coatings whose properties, eg. B. the corrosion resistance, fully satisfy. It also remains a large proportion of unsaturated groups in the cured Coating, in turn, with time due to the subsequent Impaired polymerization of these groups becomes. Finally, these coatings are subject to surface shrinkage and other irregularities when in Thicknesses above 50 μm are applied, which indicates a pronounced Difference in hardenability between the coating surface and its interior.

The known electrophoretic coating compositions further include those comprising a self-crosslinkable binder component. This contains a resin and thermally polymerizable α , β- unsaturated double bonds incorporated therein as functional groups (JP-A-53-12938 and JP-A-53-84035). It further includes coating compositions in which the binder component contains a Michael-type adduct of such a , β- unsaturated double bonds and an amino compound, wherein the adduct is decomposed by heating and the thereby regenerated α , β- unsaturated double bonds then react with a polyamine resin (JP-A-55-31889). The former compositions require a relatively high temperature for curing because the α , β- unsaturated double bonds must be polymerized together, with oxygen causing inhibition of the curing reaction, which has the disadvantage that the surface of the coating is not completely cured. The latter masses are also subject to disadvantages. Namely, the cured coatings tend to discolour, and the amino groups remain in the coating, resulting in lower water resistance. In addition, the amino compound evaporated during curing from the coating, which leads to sanitary problems.

The object of the invention is a cationic, electrophoretic To provide coating composition without release curable by-products and that is responsible for the formation of Coating is suitable, free of discoloration and other impairments are and good adhesion as well as high Resistance to water, chemicals, corrosion and the like. guarantee. The object of the invention is also a method for the electrophoretic coating of objects to provide with these masses.

Another object of the invention is to provide of cationic, electrophoretic coating compositions, the even and completely free of surface irregularities cure, even if coatings with a thickness of more than 50 microns are produced.

The invention relates to cationic, electrophoretic Coating compositions containing the following components:

• (I) A water-soluble to water-dispersible resin (hereinafter referred to as "Resin A") having primary or secondary hydroxyl groups, tertiary amino groups and an isocyanato-adduct having an α , β- unsaturated carbonyl group of the formula I. in which R₁ is a hydrogen atom or a methyl group and Y is one of the radicals where n is an integer of 1 to 4, 1 is 0 or 1, m is an integer of 0 to 20, R₂ is a hydrogen atom or a hydrocarbon group of 1 to 4 carbon atoms, and A is a divalent hydrocarbon group 1 to 20 carbon atoms; and
• (II) at least one curing catalyst from the group Metal hydroxides, metal salts of organic acids, quaternary ammonium bases, quaternary ammonium salts of organic acids, quaternary phosphonium, quaternary Phosphonium salts of organic acids, tertiary Sulfonium bases, tertiary sulfonium salts of organic Acids and alkali metal alkoxides.

The invention further provides a method for electrophoretic Coating of objects with the above Masses, the objects serve as a cathode.

The invention also provides electrophoretic coating compositions containing a water-soluble to water-dispersible resin (hereinafter referred to as "Resin B") containing an isocyanate-adduct having an α , β- unsaturated carbonyl group of the formula I, primary or secondary hydroxyl groups and at least one onium salt of an organic Acid from the group of quaternary ammonium salts of organic acids, quaternary phosphonium salts of organic acids and tertiary sulfonium salts of organic acids.

Furthermore, the invention relates to an electrophoretic coating method, in which a used as a cathode Coated with the above composition becomes.

The invention further provides electrophoretic coating compositions which comprise a mixture (hereinafter referred to as "mixture C") of a resin having primary or secondary hydroxyl groups and a resin having an isocyanate-adduct of formula I with α , β- unsaturated carbonyl groups, wherein at least one of the resins of the mixture C contains tertiary amino groups in an amount sufficient to render the mixture C water-soluble or water-dispersible upon neutralization; and the aforementioned curing catalyst.

The invention further provides a method for electrophoretic Coating of objects with the aforementioned Mass, wherein the objects serve as a cathode.

The invention also relates to a cationic electrophoretic Coating mass consisting essentially of a mixture (hereinafter referred to as "mixture D") of a Resin having a radical of formula I and a resin with contains a content of primary or secondary hydroxyl groups, wherein at least one of the resins of the mixture D is the The above-mentioned onium salt of an organic acid in an amount sufficient, the mixture D water-soluble or water dispersible.

Finally, the invention relates to a method for the electrophoretic coating of articles with the aforementioned masses, wherein the articles serve as a cathode. Investigations carried out in the context of the present invention have shown that α , β- ethylenically unsaturated double bonds in the resin containing the isocyanate-adduct moiety of the formula I containing an α , β- unsaturated carbonyl group undergo an addition reaction with hydroxyl groups in the presence of a specific curing catalyst the resin cures at relatively low temperatures to form a coating which adheres well to various substrates and sub-layers and has high resistance to water, discoloration, chemicals, corrosion and the like. In this case, the resin can cure evenly and completely free of surface irregularities, such as flaking and surface shrinkage, and without a risk of sanitary problems even in the formation of coatings with a thickness of more than 50 microns. From these findings, it has been possible to provide the coating compositions of the present invention comprising a resin having both the α , β- unsaturated carbonyl group-containing isocyanate adduct moiety and the hydroxyl group or a mixture of resins individually having these groups and the hydroxyl groups, and contain the specified curing catalyst. Also contemplated are coating compositions containing the resin or resin mixture and an organic acid onium salt attached to the resin. These coating compositions are suitable for carrying out cationic, electrophoretic coating processes.

Examples of hydrocarbon radicals represented by R₂ with 1 to 4 carbon atoms in the context of the radicals of the formula I. are methyl, ethyl, propyl, butyl, propenyl and branched Homologs of it. Examples of bivalent represented by A Hydrocarbon radicals having 1 to 20 carbon atoms are divalent aliphatic hydrocarbon radicals, such as Methylene, ethylene, propylene, butylene, amylene, hexylene, Heptylene, octylene, nonylene, decals, propenylene and ver  branched homologs thereof, alicyclic divalent hydrocarbon radicals, such as cyclopentylene, cyclohexylene

and aromatic divalent hydrocarbon radicals, such as

The resin A used in the invention contains a radical of formula I, primary or secondary hydroxyl groups and tertiary amino groups and can be prepared by various methods. Preferably, the resin A is prepared by reacting 1 mole of a hydroxyl group-containing α , β- unsaturated carbonyl compound such as 2-hydroxyethyl (meth) acrylate or N-methylol (meth) acrylamide with 1 mole of a diisocyanate compound in the presence or absence of a catalyst with or without an inactive solvent at a temperature of about 0 to about 150 ° C for about 1 to about 10 hours to an isocyanate adduct (hereinafter referred to as "adduct (a)") containing α , β- unsaturated carbonyl groups and free isocyanate groups reacting the adduct (a) with a compound or a resin containing tertiary amino groups and more than the equivalent amount of primary or secondary hydroxyl groups based on the isocyanate groups, and mixing the isocyanate groups in the adduct (a) with some of the hydroxyl groups in the hydroxyl group-containing compound or the resin in an inactive organic solvent (used as needed) in Gegenwa rt or absence of a catalyst at a temperature of about 0 to about 150 ° C for about 1 to about 10 hours.

Examples of suitable hydroxyl-containing α , β- unsaturated carbonyl compounds are hydroxyl-containing (meth) acrylamides, (meth) acrylates and the like. Specific examples of such compounds are 2-hydroxyethyl (meth) acrylate, N-methylol (meth) acrylamide, 4 Hydroxybutyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate and the like. Among them, hydroxyl group-containing acrylamide and acrylate compounds are particularly desirable in terms of curability of the resulting resin. Particularly preferred is the use of N-methylolacrylamide, since the resulting resin is characterized by its resistance to hydrolysis, adhesion and corrosion resistance.

The diisocyanate compound is preferably to a compound containing two free isocyanate groups in the molecule contains, which differ from each other in terms of their reactivity differ. Examples of such compounds are 2,4-tolylene diisocyanate, m-xylylene diisocyanate, methylcyclohexane 2,4-diisocyanate, 1,3-isocyanate-methylcyclohexane, Isophorone diisocyanate and the like

Examples of catalysts that are suitable for the aforementioned Suitable reactions are triethylamine, dimethylaminoethanol, Pyridine, tributylamine and similar tertiary amines, organotin compounds and the like.

The inactive solvent used for the above reactions is a solvent capable of dissolving or dispersing the aforementioned isocyanates and the α , β- unsaturated carbonyl compounds or the adduct (a) and the other reactants. and free of active hydroxyl groups which react with the isocyanate group. Examples of such solvents are aromatic hydrocarbon solvents such as xylene and toluene, ketone solvents such as methyl ethyl ketone, acetone, methyl isobutyl ketone and cyclohexanone, ethereal solvents such as ethylene glycol dimethyl ether and diethylene glycol dimethyl ether and the like. Using moderate reaction conditions, secondary alcohols such as isopropyl alcohol and 1-methoxy can also be used 2-propanol and tertiary alcohols, such as tert-butyl alcohol.

In the case of the compound or the resin, the tertiary amino groups and primary or secondary hydroxyl groups and the can be implemented with the adduct (a), it can be any Compounds or resins with an average of at least 2.0 hydroxyl groups in the molecule and 0.5 to 3.0 moles of tertiary Amino groups per kg of the compound or the resin act. Examples of such compound or resins are acrylic polyols, Polyester polyols, polyether polyols, alkyd resins, Caprolactone polyol adducts, epoxy-amine products, urethane polyols and similar compounds or hardness containing tertiary amino groups.

Suitably, the resin A used according to the invention contains tertiary amino groups in an amount of 0.5 to 3.0 mol / kg (of the resin), on average at least 1.0 and preferably 1.5 to 100 residues of the formula I in the molecule and an average of at least 1.0 and preferably 1.5 to 100 Hydroxyl groups in the molecule, wherein the number average molecular weight 500 to 100,000 and preferably 500 to 30,000. In the presence of less than 0.5 mol / kg at tertiary amino groups, the resin is less in water dispersible and tends to form a coating composition or an electrophoretic coating bath of lesser Stability. Exceeds the amount of tertiary amino groups 3.0 mol / kg, so there is a tendency for a reduced electrophoretic efficacy, causing the production complicated by thick coatings or impaired Scattering results.

Contains the resin 1 on average less than 1.0 residues of formula I or hydroxyl groups, so the mass is not completely hardened and leads to coatings of less Water resistance, which is undesirable. Also, is the molecular weight below 500, the formed mass is suitable  not for the production of coatings, in satisfactory Are curable while at a molecular weight of more than 100 000 of the electrophoretically deposited Coating for the formation of impaired flowability tends so that no hardened coating with smoother Surface yields.

The resin B used in the invention contains a remainder of Formula I, primary or secondary hydroxyl groups and the aforesaid onium salt of an organic acid. This resin is preferably prepared by the following methods. For example can be prepared by adding the adduct (a) with a compound or a resin containing Hydroxyl groups and the onium salt of an organic acid usually in an inactive organic solvent at 0 to 100 ° C for 1 to 10 hours or by reacting Epoxy groups and hydroxyl-containing resin with the Adduct (a) usually in an inactive organic solvent in the presence or absence of a catalyst at 0 to 150 ° C for 1 to 10 hours, and the resulting Product with an onium salt-forming compound, e.g. B. tertiary amino compounds, phosphines or thioethers, and with a salt-forming organic acid at 20 to 100 ° C 1 to react for 10 hours. The same inactive organic Solvents and catalysts described above for the resin A have been listed are suitable for these reactions. The resin B is also in relation to the Content of radicals of the formula I, the content of hydroxyl groups and the number average molecular weight and with respect to the preferred ranges of these values by the same Product as for the resin A. The onium salt of the organic acid is preferably in an amount in the range of 0.2 to 1.5 mol / kg and preferably from 0.3 to 1.2 mol / kg (resin). If this salt content is less than 0.2 mol / kg, the result is one lower dispersibility in water and thus a lower Stability of the resulting coating composition and the resulting prepared electrophoretic bath. Salt contents of  more than 1.5 mol / kg lead to a lower electrophoretic Effectiveness and bring difficulties in the production thick coverings and reduce that Scattering, which is undesirable.

The compound or the resin, the hydroxyl groups and the Onium salt of the organic acid, and with the adduct (a) to be implemented, included on average at least 2 hydroxyl groups in the molecule and 0.2 to 1.5 mol / kg on the onium salt of the organic acid. The number average the molecular weight is 500 to 100,000 and preferably 500 to 30 000. If these conditions can be fulfilled, any known resins without special Restrictions are used. Special examples for such compounds or resins are acrylic polyols, polyester polyols, Polyether polyols, alkyd resins, caprolactone polyol adducts, Epoxy resins, urethane polyols and similar compounds or resins containing the specified onium salt of an organic Contain acid.

In the epoxy group and hydroxyl group-containing compound or resin to be reacted with the adduct (a), These are, for example, epoxy resins of bisphenol A type, bisphenol F type epoxy resins, epoxy resins of Bisphenol S-type or similar reaction products of Bisphenols and epichlorohydrin, novolak epoxy resins, glycidyl ethers of polyether polyol, glycidyl ether of polyol or

Hereinafter, the method for the formation of the onium salt in the resin explained in more detail.  

The resin containing a radical of the formula I and contained in the mixture C or mixture D used according to the invention is preferably a product obtained by reacting the adduct (a) with the hydroxyl groups of a resin containing on average at least 1.0 hydroxyl groups in the molecule or by reacting a hydroxyl-containing, α , β- unsaturated carbonyl compound has been obtained with an isocyanate group-containing resin. Examples of suitable hydroxyl-containing resins are the already mentioned products, such as acrylic polyols, polyester polyols, polyether polyols, alkyl resins, epoxy resins and Urethanpolyolharze containing an average of at least 1.0 hydroxyl groups in the molecule. Examples of hydroxyl-containing, α , β- unsaturated carbonyl compounds are the products already mentioned for the adduct (a). Examples of suitable resins containing isocyanate groups are polymers which consist of an unsaturated monomer containing isocyanate groups, such as isocyanatoethyl (meth) acrylate, α , α- dimethyl-m-isopropenylbenzyl isocyanate or a reaction product of 1 mole of the abovementioned diisocyanate compounds and 1 mole of hydroxyl-containing (meth) acrylate, are obtainable by subjecting the unsaturated monomer to homopolymerization or copolymerizing the monomer with another radically polymerizable unsaturated monomer. Also suitable are resins obtained by reacting a hydroxyl-containing resin with the diisocyanate compound. Examples of suitable hydroxyl-containing resins are the already mentioned products, such as acrylic polyols, polyester polyols, polyether polyols, alkyd resins, epoxy resins, urethane polyols and similar resins.

The resin containing a radical of formula I for use in mixture C and in mixture D has an average of at least 1.0 radicals of the formula I and preferably 1.5 to 100 Radicals of the formula I in the molecule and has a number average of the molecular weight in the range of 500 to 100,000 and preferably from 500 to 30,000. The resin can be free hydro  xyl groups contained in the molecule. Does the resin contain less as 1.0 radicals of the formula I, so there is no complete Hardening of the mass and there is an undesirable coating of poor water resistance. Is the molecular weight over 100,000, the resin is less in solvents soluble and it can not form a stable resin solution.

In the primary or secondary hydroxyl-containing Resin for use in the mixture C and in the mixture D is a product that averages at least 2 and preferably 2 to 100 primary or secondary hydroxyl groups in the molecule. Examples of such resins are Acrylic polyols, polyester polyols, alkyl resins, epoxy resins, Urethane polyol resins and the like. The resin preferably has one Number average molecular weight of 500 to 100,000 and especially from 500 to 30,000.

In the case of the mixture C tertiary amino groups in the resin containing a radical of the formula I and / or in the resin containing a primary or secondary hydroxyl group be contained in such an amount that the mixture C in Water becomes soluble or dispersible. The content of tert.- Amino groups in the mixture C is preferably in the range of 0.5 to 3.0 mol / kg, based on the total amount of resins in Mixture C.

In the case of the mixture D, the specified onium salt of a organic acid in the resin with a radical of the formula I. and / or in the resin containing primary or secondary Hydroxyl groups may be present in an amount that sufficient that the mixture D soluble or dispersible in water becomes. The content of onium salt of an organic Acid in the mixture D is preferably in the range of 0.2 to 1.5 mol / kg, based on the total amount of resins in the mixture D. The process for producing the onium salt in the resin will be described later.  

If the content of tertiary amino groups in the mixture is C or the content of onium salt of an organic acid in the mixture D below the range mentioned above, it follows a lower dispersibility of the mixture in water, resulting in a lower stability of the mass obtained leads, while higher shares outside the specified Range, to a lower electrophoretic Efficiency lead to difficulties in the production of prepare thick coatings and the tendency to lower Strengthens spill power.

The tertiary amino groups can be introduced into the mixture C, for example in the preparation of the resin having the radical of the formula I, by adding the adduct (a) with the resin, in the molecule an average of at least 1.0 hydroxyl groups and the required number of tertiary amino groups has reacted. Further, a method is also suitable in which in the reaction of the hydroxyl group-containing α , β- unsaturated carbonyl compound with the isocyanate group-containing resin, a compound having a content of tertiary amino groups and hydroxyl groups in one molecule is reacted with the isocyanate group-containing resin. Another possibility is to use the amino groups in the mixture C using a resin containing a primary or secondary hydroxyl group and also tertiary amino groups as a hydroxyl-containing resin to be used in combination with the resin containing the radicals of the formula I, introduce.

The onium salt of an organic acid can be added to the mixture D For example, by looking at one of the above method for introducing the tertiary amino groups operated in the mixture C, wherein the tertiary amino group replaced by the onium salt of an organic acid becomes. This introduction can also be achieved by Epoxy groups in at least one of the resins of the mixture D  introducing and forming the epoxy groups with an onium salt Group, as used for example in a tertiary amino compound, a phosphine or thioether, and with a salt-forming organic acid for 1 to 10 hours at 20 to 100 ° C reacted.

In the preparation of the cationic, electrophoretic coating compositions, the resins A and B or mixtures C and D are used in the mixture. In mixtures C and D, the molar ratio of Radical of the formula I to the primary or secondary hydroxyl groups, d. H. the molar ratio of residual / hydroxyl groups, im Range from 10/1 to 1/20 and preferably from 5/1 to 1/10. A molar ratio of these functional groups of more than 10/1 or less than 1/20 is not desirable then there is a deteriorated hardenability or similar Difficulties arise.

In general, the ratio between the resins to be mixed in the mixture C or D is determined so that the aforementioned molar ratio is in the specified range. In admixture C or D, the resin having the radical of formula I to which the primary or secondary hydroxyl group-containing resin is generally blended in a weight ratio of the former to the latter is in the range of about 95: 5 to about 5:95. In the present invention, the isocyanate-adduct group having the α , β- unsaturated carbonyl group of the formula I can be introduced into a resin by reacting a compound or a resin having α , β- unsaturated carbonyl groups and hydroxyl groups with an isocyanate compound or an isocyanate group-containing resin, or by a hydroxyl group-containing compound or resin with a compound or a resin having unsaturated α , β- unsaturated carbonyl groups and isocyanate groups.

Furthermore, according to the invention, the tertiary ammonium groups in The resin can be introduced by looking for example an addition reaction between epoxy groups and a secondary one Amine, an addition reaction between epoxy groups and a tertiary alkanolamine, an addition reaction between isocyanate groups and a tertiary alkanolamine, an esterification reaction between carboxyl groups and a tertiary alkanolamine or an addition reaction between an unsaturated group and a secondary one Amin served.

According to the invention, at least one onium salt of an organic Acid from the group quaternary ammonium salts of organic Acids, quaternary phosphonium salts of organic Acids and tertiary sulfonium salts of organic Acids are introduced into a resin according to the following procedure.

The onium salt of an organic acid present in the resin can be represented by the following formulas:

wherein P represents the main chain of the resin; R _{a is} preferably a hydrogen atom or an optionally substituted by hydroxyl, alkoxy, ester or halogen groups substituted C₁-C₈ hydrocarbon radical; and R _b , R _c and R _{d are the} same or different and each preferably represents a C₁-C₁₄ organic group, or R _b and R _c or R _b , R _c and R _d together with the nitrogen atom, the phosphorus atom or the sulfur atom to which they are attached, optionally form a heterocyclic ring.

The represented by R _b , R _c and R _d C₁-C₁₄-organic radicals are not particularly limited, unless they cause a significant impediment to the ionization of ammonium salts, phosphonium salts or sulfonium salts. In general, suitable as such organic radicals C₁-C₁₄ hydrocarbon radicals which optionally contain heteroatoms, z. As an oxygen atom in the form of a hydroxyl group, alkoxy group or the like.

Such hydrocarbon radicals include aliphatic, alicyclic or aromatic hydrocarbon radicals, such as Alkyl, cycloalkyl, cycloalkylalkyl, aryl and aralkyl. at The above alkyl radicals may be straight chain or branched chains, wherein the alkyl radicals are preferably not more than 8 and especially 1 to 6 carbon atoms respectively. Examples of such alkyl radicals are methyl, ethyl, n- or isopropyl, n-, iso-, sec- or tert-butyl, pentyl, heptyl, octyl and the like. Preferred Cycloalkyl radicals and cycloalkylalkyl radicals are those with 5 to 8 carbon atoms, e.g. Cyclopentyl, cyclohexyl, Cyclohexylmethyl and cyclohexylethyl. Suitable aryl radicals are phenyl, toluyl, xylyl and the like. A preferred example for aralkyl radicals is benzyl and the like.

Examples of preferred hydrocarbon radicals with at least a heteroatom, e.g. As an oxygen atom, are hydroxyalkyl radicals (in particular hydroxy-lower-alkyl radicals),  such as hydroxymethyl, hydroxyethyl, hydroxybutyl, hydroxypentyl, Hydroxyheptyl and hydroxyoctyl; alkoxyalkyl, (especially lower alkoxy-lower alkyl radicals), e.g. Methoxymethyl, Ethoxymethyl, ethoxyethyl, n-propoxyethyl, isopropoxymethyl, n-butoxymethyl, isobutoxyethyl and tert-butoxyethyl.

When R _b and R _c or R _b , R _c and R _d together with the nitrogen, phosphorus or sulfur atom to which they are attached form a heterocyclic ring, the onium cation can be represented by the following formulas:

or the like.

The anion in the organic onium salt can be carried ^- reflect OCOR _a, wherein R _a has the meaning defined above. Examples of represented by R _a C₁-C₈ hydrocarbon radicals are aliphatic, alicyclic or aromatic hydrocarbon radicals having 1 to 8 carbon atoms such as alkyl, alkenyl, cycloalkyl, cycloalkenyl, aryl and aralkyl. Of these groups, alkyl and alkenyl are preferred, which may be straight-chain or branched radicals. Particularly preferred are lower alkyl radicals and lower alkenyl radicals, for. For example, methyl, ethyl, n- or isopropyl, n-, iso-, sec- or tert-butyl, pentyl, heptyl, octyl, vinyl and methyl-substituted vinyl. Preferred hydroxyl-substituted hydrocarbon radicals are hydroxyalkyl radicals (especially hydroxy-lower-alkyl radicals), e.g. Hy droxymethyl, hydroxyethyl, hydroxybutyl, hydroxypentyl, Hy droxyheptyl and hydroxyoctyl. Preferred alkoxy substituted hydrocarbon radicals are alkoxyalkyl radicals (especially lower alkoxy-lower alkyl radicals), e.g. B. Meth oxymethyl, ethoxymethyl, ethoxyethyl, n-propoxymethyl, iso propoxymethyl, n-butoxymethyl, isobutoxyethyl and tert-butoxy-oxyethyl and the like. Preferred, substituted by ester radicals hydrocarbon radicals are lower Alkyloxycarbonylalkylreste, z. B. Methyloxycarbonylmethyl, Propyloxycarbonylethyl, Ethyloxycarbonylpropyl and Methoxycarbonylbutyl, lower al kyloxycarbonylalkenylreste, z. B. Methoxycarbonylethylenyl and Ethyloxycarbonylethylenyl and the like. Examples of preferred substituted by halogen atoms hydrocarbon radicals are halogenated lower alkyl radicals, eg. Chloromethyl, bromomethyl, iodomethyl, dichloromethyl, trichloromethyl, chloroethyl, trichloroethyl and the like.

Among the organic acids useful in the formation of the aforementioned anions are acetic, formic, propionic, trichloroacetic, acrylic, methacrylic, lactic, hydroxyacetic, crotonic, chloroacetic, monomethylmaleate, monoethylfumarate, monomethylitaconate, and the like Dissociation constants (pK _a ) of not less than 1 × 10 ^-5 particularly preferred, e.g. Acetic acid, formic acid, acrylic acid, lactic acid and the like. Onium salts of these organic acids provide satisfactory improvements in the hardenability of the electrodeposited coatings and in the water resistance of the cured coatings. The onium salts can be introduced into the resin by, for example, methods (i) and (ii) described below.

(i) In this process, a tertiary amine, a phosphine or thioethers containing a halogenated alkyl radical Resin in the absence or presence of an inert implemented organic solvent. The product obtained is subjected to ion exchange reaction to the halogen atom to be replaced by hydroxyl. Then follows the Reaction with an organic acid.

When a tertiary amine is used to react with the resin, thus, the reaction scheme can be represented as follows:

wherein X is a halogen atom and P, R _b , R _c and R _{d have} the meaning defined above.

When a phosphine is used in place of the above tertiary amine, in the above reaction scheme, N is to be replaced by P. If a thioether is used instead of a tertiary amine, replace N with S in the above reaction scheme and delete R _d .

The reaction of the resin with a tertiary amine becomes, for example by heating to a temperature of about 100 carried out to about 150 ° C. The conversion is about 1 to finished about 20 hours.

The obtained reaction product is subjected to ion exchange. The resulting compound is treated with an organic Acid reacted to the onium salt of the organic To get acid. The method is carried out, for example, by placing the reaction product on a with a bead  from a anion exchange resin packed column touches, to replace halogen atoms by hydroxyl groups. Subsequently, the resulting compound with an organic Acid mixed.

(ii) In this process, a tertiary amine, a Phosphine or a thioether and an organic acid with the resin having the 1,2-epoxy group in the absence or in Reacted in the presence of an inert solvent. Will the Reaction of the resin with a tertiary amine, so the following reaction scheme applies:

wherein P, R _b , R _c and R _{d have} the meaning defined above.

When using a phosphine in place of the tertiary amine, in the above reaction scheme, as in case (i), the N is to be replaced by P. When using a thioether instead of the tertiary amine, as in the above case (i), replace the N by S and delete the -R _d .

The reaction of the resin with a tertiary amine and a organic acid is, for example, under heating a temperature of about 40 to 80 ° C performed. The Um  is completed within about 1 to about 20 hours.

Examples of inert solvents used in the reactions (i) and (ii) can be used are solvents from Ether alcohol type, such as ethylene glycol, monobutyl ether, ethylene glycol monoethyl ether, ethylene glycol monomethyl ether, diethy glycol monobutyl ether, diethylene glycol monoethyl ether and diethylene glycol monomethyl ether; Solvent of ether type, such as dioxane, tetrahydrofuran, ethylene glycol dimethyl ether, Diethylene glycol dimethyl ether and ethylene glycol diethyl ether, Alcohol-type solvents such as ethanol, propanol and butanol; Ester type solvents such as ethylene glycol monomials thyletheracetat; Ketone-type solvents, such as Me ethyl ethyl ketone and methyl isobutyl ketone; and the like.

If the resin is an acrylic resin, then that can be Onium salt of an organic acid according to the above Introduce methods (i) and (ii). The introduction can also by polymerization of (meth) acrylic acid ester monomers of following formula

wherein R _{f represents} a hydrogen atom or a methyl group; -W⁺ has the following meanings

and R _a , R _b , R _c and R _d are as defined above, can be carried out in the usual way, alone or with other comonomers which are copolymerizable with the ester monomer.

In the case of in combination with the resin A or the mixture C too used curing catalyst is at least a basic compound from the group of metal hydroxides, Metal salts of organic acids, quaternary ammonium bases, quaternary phosphonium bases, tertiary sulfonium bases, Salts of these compounds with organic acids and Alkali metal.

Examples of suitable metal hydroxides are alkali metal hydroxides, such as sodium hydroxide, potassium hydroxide and lithium hydroxide, Alkaline earth metal hydroxides, such as calcium hydroxide, Magnesium hydroxide and barium hydroxide, and the like The above compounds are also nickel hydroxide, Copper hydroxide, molybdenum hydroxide, lead hydroxide, iron hydroxide, Chromium hydroxide, manganese hydroxide, tin hydroxide, cobalt hydroxide and the like.

The quaternary ammonium base, the quaternary phosphonium base and the tertiary sulfonium base can be defined by the following Play formulas:

wherein R _b , R _c , R _d and R _{e are the} same or different and are each preferably a hydrogen atom or C₁-C₁₄ organic radicals and in which in particular at least one of R _b , R _c , R _d and R _{e is} a C₁-C₁₄ -organic radical or R _b and R _c or R _b , R _c and R _d together with the nitrogen, phosphorus and sulfur atom to which they are attached form a heterocyclic ring.

As C₁-C₁₄-organic radicals which are represented by R _b , R _c , R _d and R _e , the same C₁-C₁₄-organic radicals, as described above for R _b , R _c and R _d in the context of Onium salts of organic acid have been listed in the resin. When R _b and R _c or R _b , R _c and R _d together with the nitrogen, phosphorus or sulfur atom to which they are attached form a heterocyclic ring, the cation is represented, for example, by the following formulas:

and the like.

As curing catalysts and organic salts of the aforementioned metal hydroxides and onium bases and alkali metal alkoxides be used.

Examples of typical organic acids used for conversion the metal hydroxides and the onium bases in organic salts can be used are the same organic acids, as to the formation of an anion in the onium salt of the organic Acid within the resin; the octenoic acid, the naphthenic acid; abietic acid and the like can be used. Examples of typical suitable alkali metal alkoxides are Sodium ethoxide, sodium methoxide, potassium methoxide, potassium ethoxide and the like.

These include metal hydroxides and metal salts of organic Acids are preferred since they have coatings of good hardenability at low temperatures and good water resistance at high temperatures (about 80 to 100 ° C).

For use with the mixture C or the resin A, the free of an onium salt of an organic acid, the Curing catalyst in an amount of about 0.001 to about 20 parts by weight, preferably from about 0.1 to about 10 parts by weight and especially from about 0.5 to about 5 parts by weight used per 100 parts by weight of resin solids. A lot Less than 0.001 parts by weight leads to impairment water resistance, adhesion and physical Properties of the coating, indicating an inadequate Hardenability is due. On the other hand leads  an amount of more than 20 wt .-% to a reduction of catalytic effect and thus to a catalyst waste. In addition, it probably comes to an impairment the water resistance of the coating, so that these high levels are not preferred.

For use with the mixture D or the resin D in which the Onium salt is bound to the resin, which is a catalytic Does not have the curing catalyst in each Case be used. However, the curing catalyst can (preferably a metal hydroxide or a metal salt of a organic acid) are used simultaneously, whereby improved hardenability at low temperatures achieved.

Among the constituents resin A, resin B, mixture C and mixture D, mixtures C and D are preferred in view of storage stability since the resin containing the radical of formula I can then be separated from the hydroxyl group-containing resin. It is particularly desirable that the resin contained in the mixture C or D and containing the isocyanate-adduct group with α , β- unsaturated carbonyl groups be free of hydroxyl groups. When there are α , β- unsaturated carbonyl groups and free hydroxyl groups in the same resin, it is desirable to store the resin in a concentrated state before it is neutralized and rendered water-soluble or dispersible. Precautions are taken, for example, storage of the resin at low temperatures to preclude gelation during storage due to reaction between the two groups.

The cationic, electrophoretic Coating mass can be coloring pigments, stretching Pigments, anti-corrosion pigments, dyes, pigment dispersing resins, pigment dispersing agents  tel, leveling agent, anti-foaming agent, anti-skid agent, Solvents and the like. Included.

With regard to the solvent to be used, there are no special restrictions, provided it is for usual cationic, electrophoretic coating compositions. These solvents include those in water 25 ° C in an amount of at least 5% are soluble, for. B. Isopropanol, butanol and similar alcohols, ethylene glycol mo noalkyl ether, propylene glycol monoalkyl ether, diethylene glycol monoalkyl ethers, dipropylene glycol monoalkyl ethers, ethylene glycol Koldialkylether, Diethylenglykoldialkylether and dioxane and similar cyclic ethers. Preferably, these solvents in an amount of 0 to 100 parts by weight per 100 Parts by weight solids used in the bath. Suitable are also solvents which in water of 25 ° C a solubility less than 5%, e.g. B. 2-ethylhexyl alcohol, n-octyl alcohol, benzyl alcohol and similar alcohols, as well as mono- and diethers of alcohols and glycols, such as Ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, ethylene glycol monooctyl ether, ethylene glycol monobenzyl ether, Ethylene glycol monophenyl ether, diethylene glycol mo nooctyl ether, diethylene glycol monophenyl ether, dipropylene glycol colmonophenyl ether, dipropylene glycol monooctyl ether, propy glycol monooctyl ether, propylene glycol monobenzyl ether, Pro pylene glycol monophenyl ether, diethylene glycol dibutyl ether, Diethylene glycol dioctyl ether, dipropylene glycol dibutyl ether and dipropylene glycol dioctyl ether. These and other solvents, such as aromatic, aliphatic and alicyclic hydrocarbons as well as ketones, which are also suitable are preferably in an amount of 0 to 20 parts by weight used per 100 parts by weight of the solids content in the bath. Pigments and additives that are suitable for common cationic, electrophoretic coating compositions are suitable, without special restrictions in terms of quantity or type of this Components are used. However, pigments are in the With regard to the stability of the bath preferably in one  Amount up to 50% by weight, based on the resin solids, used.

In the case of using mixtures C or D can be process them into a coating mass by mixing dispersed therein pigments or the mixture is neutralized and then dispersed in water or by adding pigments dispersed in only one of the resin components of the mixture and then neutralizing the other resin component, followed by dispersion in water. Another possibility is the resin components after neutralization, disperse separately in water and then mix the dispersions with each other.

The electrophoretic coating compositions prepared in this way are each in terms of their solids content according to the thickness of the coating to be produced or ever variable according to the coating conditions. In general is for cationic, electrophoretic coatings the Mass in the form of a bath having a solids content of 1 to 30%, wherein the article to be coated as a cathode serves.

The coating process can be applied under commonly used Conditions are performed, for. B. by one predetermined voltage (generally 10 to 500 volts) between the desired article, which is electrically conductive and serves as a cathode, and the other electrode for a predetermined period of time (generally 30 seconds to 10 Minutes). The article is then removed from the bath and directly or after previous washing with water to a temperature of at least 80 ° C, preferably at least 100 ° C and especially about 120 to about 200 ° C, preferably at least 5 minutes and especially about 10 to heated for about 60 minutes, creating the desired electrophoretic Plating can be obtained which is a satisfactory Appearance and excellent features  has. Under controlled electrophoretic coating conditions it is also possible to form coatings have large thicknesses of about 50 to 100 microns and the nevertheless satisfactory and free of surface irregularities are where no dirty curing when Burning occurs, which is not abnormal surface texture due to flaking, their surface not subject to shrinkage and the like and that does not yellow.

The electrophoretic coating process as above carried out with a method under constant tension can be carried out, while achieving more favorable Results performed after a slow startup procedure be, the voltage gradually from 0 volts to the specified Tension is raised. Furthermore, a method be applied under constant current, in which by the Bad a constant current is passed. Finally, you can also the aforementioned methods are combined.

It is believed that the electrophoretic coating of the present invention, upon heating, is due to the addition reaction of the hydroxyl groups with the α , b- unsaturated carbonyl groups, which is supported by the following findings: the IR absorption spectrum undergoes a change, indicating the disappearance of unsaturated groups; the curing reaction does not give by-products; and finally, the composition shows no change in its hardenability even when large amounts of polymerization inhibitors are incorporated to inhibit the thermal polymerization between the unsaturated groups.

The inventive method is electrically to any conductive objects applicable and is particularly suitable for applications where high water resistance, Corrosion resistance and resistance to Discoloration arrives. The coating formed according to the invention can act directly as such or along with one on top of it  be placed further coating. The electrophoretic For example, coating can be applied to different ones Parts, steel furniture, distribution boxes and electrical Household appliances are trained. The coating can, as mentioned, with another, trained on it Cover be provided, for example, on motor vehicle bodies, Automotive parts, household electrical appliances and steel furniture and the like., d. H. for application purposes, in terms of even more perfect properties in terms of Surface texture or appearance arrives and at which even better coating properties than in the former Case are required.

Hereinafter, the invention by way of examples and Comparative examples explained in more detail, wherein all Refer to parts and percentages by weight.

Preparation of the adduct (a) Production Example 1 Preparation of adduct (a-1) isophorone 444 parts N-methylolacrylamide 202 parts methyl ethyl ketone 100 parts

The mixture of the above components is poured into a four-necked flask brought and reacted at 80 ° C until a NCO value of 91. The adduct (a-1) is obtained.

Production Example 2 Preparation of adduct (a-2) tolylenediisocyanate 174 parts N-methylolacrylamide 101 parts methyl ethyl ketone 100 parts

The mixture of the above components is poured into a four-necked flask brought and reacted at 25 ° C until a NCO value of 121. The adduct (a-2) is obtained.

Production Example 3 Preparation of adduct (a-3) isophorone 444 parts 2-hydroxyethyl acrylate 232 parts methyl ethyl ketone 100 parts

The adduct (a-3) is prepared in the same manner as in Production Example 1 manufactured, with the modification that the the aforementioned mixture is used. The mixture is reacted, until an NCO value of 108 results. You get that Adduct (a-3).

Production Example 4 Preparation of adduct (a-4) tolylenediisocyanate 174 parts 2-hydroxypropyl acrylate 130 parts methyl ethyl ketone 60 parts

The adduct (a-4) is prepared in the same manner as in Production Example 2 manufactured, with the modification that the the aforementioned mixture is used. The mixture is reacted, until an NCO value of 115 results. You get that Adduct (a-4).

Production Example 5 Preparation of adduct (a-5) isophorone 222 parts 2-hydroxyethyl acrylate 116 parts methyl ethyl ketone 145 parts

The mixture of the above components is poured into a four-necked flask brought and reacted at 80 ° C until a NCO value of 87. The adduct (a-5) is obtained.  

Preparation Example 6 Preparation of adduct (a-6)

The adduct (a-6) is prepared in the same manner as in Preparation Example 1 manufactured, with the modification that the above mixture is used. The mixture is reacted, until an NCO value of 80 results. You get that Adduct (a-6).

Preparation of Resin A Containing Hydroxyl Groups and tertiary amino groups Preparation Example 7 Preparation of Resin Varnish A-1

The mixture of the above components is poured into a four-necked flask brought and reacted at 80 ° C for 3 hours, after which 746 parts of adduct (a-1) are added. Subsequently the mixture is reacted at 80 ° C for 10 hours and then admixed with 540 parts butylcellosolve. You get the Resin paint A-1 with a solids content of 70%.

The resulting resin has a molecular weight of about 2100, 0.95 mol / kg (resin) of tertiary amino groups, two remaining Groups of formula I per molecule and 8 hydroxyl groups per Molecule up.  

Preparation Example 8 Preparation of Resin Varnish A-2

The mixture of the above components is allowed to stand for 3 hours 80 ° C, after which 670 parts of the adduct (a-2) and 100 Parts of ethylene glycol dimethyl ether may be added. The mixture is then reacted for 8 hours at 80 ° C. This will be the reaction mixture with 361 parts of ethylene glycol monoethyl ether added. The resin varnish A-2 is obtained.

Production Example 9 Preparation of resin varnish A-3 2-hydroxyethyl methacrylate 300 parts N, N-dimethylaminoethyl 157 parts styrene 300 parts n-butyl acrylate 243 parts benzoyl peroxide 20 parts

Diethylene glycol dimethyl ether (500 parts) are in a Four-necked flask and heated to 110 ° C with stirring. Subsequently, the mixture of the above components added dropwise within 3 hours. The resulting mixture is kept at the same reaction temperature for 2 hours and then 335 parts of the adduct (a-2), followed by 10 hours is implemented. The resin varnish A-3 is obtained.  

Preparation 10 Preparation of resin varnish A-4

The resin varnish A-4 is prepared in the same manner as in Preparation Example 9 using 527 parts of the adduct (a-6) instead of 335 parts of adduct (a-2). The resin varnish A-4 is obtained.

Production Example 11 Preparation of resin varnish A-5 Epicote # 152 500 parts diethanolamine 305 parts

The mixture of the above components is poured into a four-necked flask brought and reacted at 80 ° C for 3 hours, after which 728 parts of the adduct (a-4) and 100 parts of ethylene glycol dimethyl ether be added. The reaction mixture becomes 8 Hours reacted at 80 ° C. Then 300 parts of ethylene glycol monoethyl ether added. The resin varnish is obtained A-5.

Production Example 12 Preparation of resin varnish A-6 2-hydroxyethyl methacrylate 300 parts N, N-dimethylaminoethyl 157 parts styrene 300 parts n-butyl acrylate 243 parts benzoyl peroxide 40 parts

Diethylene glycol dimethyl ether (590 parts) are in a Four-necked flask and heated to 110 ° C with stirring. The mixture of the above components is within 3 hours, with the same reaction temperature 2 hours is maintained. It is then cooled to 80 ° C. The adduct (a-1) (373 parts) is added and the Mixture is reacted for 10 hours. The resin varnish is obtained A-6.  

Preparation 13 Preparation of resin varnish A-7

Resin paint A-7 is prepared in the same manner as in Production Example 7 using a mixture of 540 Divide ethylene glycol monobutyl ether and 21 parts (0.1% calculated as solids) of hydroquinone instead of 540 parts Ethylene glycol monobutyl ether prepared.

Preparation of Resin B Containing Residues of the Formula I, Hydroxyl Groups and Onium Salt Production Example 14 Preparation of resin varnish B-1 Epicote # 1002 1256 parts triethylamine 101 parts acrylic acid 144 parts 1-methoxy-2-propanol 388 parts

The mixture of the above components is allowed to stand for 6 hours 60 ° C in the same manner as in Preparation Example 7 implemented and then with 600 parts of the adduct (a-2) added. The reaction mixture is added for a further 8 hours 70 ° C implemented. The resin varnish B-1 is obtained.

Production Example 15 Preparation of resin varnish B-2 glycidyl 284 parts styrene 206 parts 2-hydroxyethyl methacrylate 260 parts n-butyl acrylate 250 parts tert-butyl peroctoate 30 parts

Diethylene glycol dimethyl ether (500 parts) are in a Brought four-necked flask and heated to 120 ° C with stirring. The mixture of the above components is within Dripped to the solution for 3 hours. The mixture is 2 hours leave at the same reaction temperature and then on  70 ° C cooled. Subsequently, 210 parts of ethylene glycol dimethyl ether, 244 parts of thiodiglycol ((HOCH₂CH₂) ₂S) and 92nd Parts of formic acid added. Then it is 4 hours at 70 ° C implemented. Then 746 parts of the adduct (a-1) are added. The mixture is reacted at 70 ° C for 8 hours. you receives the resin varnish B-2.

Preparation of Resin E Containing Residues of the Formula I or Hydroxyl Groups and Tertiary Amino Groups Production Example 16 Preparation of resin varnish E-1 2-hydroxyethyl methacrylate 130 parts N, N-dimethylaminoethyl 235 parts styrene 317 parts n-butyl acrylate 318 parts azobisisobutyronitrile 25 parts

Diethylene glycol dimethyl ether (500 parts) and 166 parts Me ethyl isobutyl ketone are placed in a four-necked flask and heated to 110 ° C with stirring. The mixture of the above Components are added dropwise within 4 hours. The reaction mixture is added dropwise within 4 hours. The reaction mixture will be 2 hours at the same temperature left and then cooled to 80 ° C. 373 parts of the adduct (A-1) are added, and the mixture is allowed to stand for 10 hours implemented at 80 ° C. The resin varnish E-1 is obtained.

Production Example 17 Preparation of resin varnish E-2 triethanolamine 149 parts Adduct (a-3) 1006 parts methyl ethyl ketone 33 parts

The mixture of the above components is placed in a four-necked flask brought and reacted at 80 ° C until the NCO value has dropped below 1. The resin varnish E-2 is obtained.  

Preparation 18 Preparation of resin varnish E-3

The mixture of the above components is poured into a four-necked flask brought and reacted at 70 ° C for 4 hours. Subsequently become 746 parts of the adduct (a-1) and 275 parts Dimethylglaim added. The mixture is reacted at 80 ° C, until the NCO value has dropped below 1. You get the Resin varnish E-3.

Preparation 19 Preparation of resin varnish E-4

The mixture of the above components is placed in a four-necked flask brought to 8 hours at 160 ° C and reacted Cooled to 80 ° C. Then 104 parts of diethanolamine and 400 Parts of propylene oxide methyl ether added. The mixture is reacted at 80 ° C for 5 hours. The resin varnish is obtained B-4.  

Production Example 20 Production of resin varnish E-5 Polytetramethylene glycol (molecular weight about 1000) 1000 parts tolylenediisocyanate 348 parts methyl ethyl ketone 500 parts

The mixture of the above components is reacted at 30 ° C, until an NCO value of 45 results. Then be Added 210 parts of diethanolamine. The mixture will continue reacted until the NCO value falls below 1. You get the Resin varnish E-5.

Production Example 21 Production of resin varnish E-6 2-hydroxyethyl methacrylate 150 parts n-butyl methacrylate 258 parts styrene 250 parts n-butyl acrylate 200 parts glycidyl 142 parts tert-butyl peroxyoctoate 40 parts

Ethylene glycol monoethyl ether (500 parts) are in a Brought four-necked flask and heated to 120 ° C with stirring. The mixture of the above components is within 3 hours dripped. Then the reaction mixture becomes 2 Leave hours at the same reaction temperature and then cooled to 70 ° C. 75 parts of N-methylethanolamine are added and the resulting mixture is 5 hours implemented at 70 ° C. The resin varnish E-6 is obtained.  

Production Example 22 Preparation of resin varnish E-7

The mixture of the above components is poured into a four-necked flask brought at 110 ° C to an acid value of Reacted 0.1, cooled to 80 ° C and then with 134 parts N-methylethanolamine added. Subsequently, the mixture 3 hours at 80 ° C implemented. The resin varnish E-7 is obtained.

Preparation of Resin F Containing Hydroxyl Groups and Onium Salt Groups Production Example 23 Preparation of resin varnish F-1 2-hydroxyethyl methacrylate 150 parts n-butyl methacrylate 329 parts styrene 250 parts n-butyl acrylate 200 parts glycidyl 71 parts tert-butyl peroxyoctoate 40 parts

Ethylene glycol monoethyl ether (500 parts) are in a Brought four-necked flask and heated to 120 ° C with stirring. The mixture of the above components is within 3 hours dripped. Then the reaction mixture becomes 2 Leave hours at the same reaction temperature and cooled to 70 ° C. Subsequently, 44.5 parts of N, N-dimethylethanolamine and 30 parts of acetic acid added. The  Mixture is reacted for 10 hours. The resin varnish is obtained F-1.

Production Example 24 Preparation of resin varnish F-2 styrene 193 parts n-butyl methacrylate 500 parts 2-hydroxyethyl acrylate 150 parts dimethylaminoethyl 157 parts azobisisobutyronitrile 50 parts

Ethylene glycol monobutyl ether (500 parts) is in a Four-necked flask, heated with stirring to 100 ° C and leave at this temperature. Then the mixture of above components are added dropwise within 3 hours. The reaction mixture is left for 2 hours at 100 ° C and then with 5 parts of azobisisobutyronitrile and 50 parts Methyl ethyl ketone within 1 hour dropwise added. The mixture is then left for 2 hours at 100 ° C. The resin varnish F-2 is obtained.

Preparation of Resin G Containing Residues of the Formula I and Hydroxyl Groups Production Example 25 Preparation of resin varnish G-1 α , α- dimethyl-m-isopropenylbenzyl isocyanate 210 parts n-butyl acrylate 540 parts styrene 250 parts benzoyl peroxide 20 parts

Diethylene glycol dimethyl ether (500 parts) are in a Brought four-necked flask and heated to 120 ° C with stirring. The mixture of the above components is within 4 hours dripped. Then the reaction mixture becomes 2 Leave hours at the same reaction temperature and then cooled to 80 ° C. 16 parts of N-methylol  acrylamide, 50 parts ethylene glycol dimethyl ether and 0.1 part Hydroquinone are added dropwise within 1 hour. hereupon The mixture is left at 80 ° C until an NCO value of 1 results. The resin varnish G-1 is obtained.

Preparation 25 Preparation of resin varnish G-2

The mixture of the above components is poured into a four-necked flask brought and reacted at 60 ° C until a NCO value of less than 1 results. The resin varnish is obtained G-2 with a solids content of 100%.

Production Example 27 Preparation of resin varnish G-3 n-butyl methacrylate 408 parts styrene 250 parts n-butyl acrylate 200 parts glycidyl 142 parts tert-butyl peroxyoctoate 40 parts

Ethylene glycol monoethyl ether (500 parts) is placed in a four-necked flask brought with stirring to 120 ° C and heated at leave this temperature. The mixture of the above Components are added dropwise within 3 hours. Subsequently the reaction mixture is at the same for 2 hours Leave reaction temperature and then cooled to 70 ° C. This is followed by 72 parts of acrylic acid, 5 parts of tetraethylammonium bromide and 0.5 part hydroquinone added. The  The mixture is reacted at 110 ° C for 5 hours. you receives the resin varnish G-3.

Preparation of a Michael-type adduct Production Example 28 Preparation of resin varnish M-1 trimethylolpropane 296 parts diethylamine 219 parts

The mixture of the above components becomes an addition reaction Michael-type 4 hours with cooling Subjected to ice. The resin varnish M-1 is obtained.

Preparation of a polyamine resin Production Example 29 Preparation of resin varnish H-1 Polytetramethylene glycol (molecular weight about 1000) 1000 parts diethylene glycol dimethyl ether 500 parts

The mixture of the above components is poured into a four-necked flask brought and left at 20 ° C. Then be 348 parts tolylene diisocyanate added dropwise within 2 hours. The mixture is reacted at 20 ° C until a NCO value of 46 results. Then be within 2 hours 685 parts of a solution of a diketimine product at 20 ° C, by reaction of diethylenetriamine with methyl isobutyl ketone was added dropwise, the methyl isobutyl ketone solution contains 78% of the diketimine product. The Mixture is left for 3 hours at 50 ° C and then mixed with 100 parts of deionized water. The obtained Solution is left for 3 hours at 80 ° C and then to Regeneration of the amino groups hydrolyzed. You get the Polyamine resin paint H-1.  

The properties of the resulting resin coatings are shown in Table I. compiled.

The storage stability evaluation test given in Table I is performed as follows.

Storage stability: An amount of 150 g of the product obtained above Resin varnish is placed in a vessel of 250 ml capacity brought. Then the vessel is closed and 1 month stored in a thermostat at 40 ° C.

The storage stability is evaluated according to the following criteria:

A: little or no increase in viscosity
B: slight increase in viscosity
C: significant increase in viscosity
D: pronounced increase in viscosity or gel binding.

Table 1

Table I - continued

Table I - continued

Example 1 Step 1

A solution of resin varnish A-1 (10 parts), 0.5 parts of carbon black, 5 Parts talcum, 3 parts diethylene glycol monoethyl ether, 0.6 Parts of acetic acid and 50 parts of deionized water mixed. The mixture is in a ball mill for 36 hours (with stones) dispersed. A pigment dispersion is obtained (Particle size of not more than 10 μm, measured by means of a grain size measuring device).

Level 2

Deionized water (432 parts), 1 part of cobalt acetate and 0.6 parts of acetic acid are mixed by means of a stirrer with 800 stirred until 1000 U / min. 90 parts of resin varnish A-1 added slowly. After the addition, the stirring process becomes more Continued for 30 minutes. 69.1 parts of the pigment dispersion are added. The mixture is then stirred for 10 minutes. A stable aqueous dispersion of a coating composition is obtained. Using this aqueous coating as electrophoretic bath and one with zinc phosphate treated plate as a cathode is 3 minutes at 280 V and a bath temperature of 28 ± 1 ° C an electrophoretic coating carried out. The plate is then filled with water washed and hardened by heating. This gives a coated Plate.

Examples 2 to 16 and Comparative Examples 1 to 5

Aqueous coating compositions are prepared according to Example 1 from prepared in Table II components. coated Plates are made by heating and curing under the in Table III conditions.

The properties of the coatings are given in Table III.  

Table II

Table II - continued

Table II - continued

Table II - continued

Table II - continued

Table III

Table III - continued

Table III - continued

Table III - continued

Table III - continued

Table III - continued

The tests in Table III are according to the following procedures carried out:

(1) Gelfraktionanteil: The removed coating is in a refluxing acetone solution of about 57 ° C immersed and extracted for 4 hours. The gel content is determined according to the following Equation calculated:

A: weight of the coating after extraction.
B: Weight of the coating before immersion in acetone.
(2) Adhesion: The test plate is cut crosswise into 100 squares of 1 mm edge length. A cellophane adhesive tape is placed on the coated surface and released by a jerky movement. The number of squares remaining on the surface is determined.
(3) Resistance to boiling water: The coated plate is immersed in boiling water for 1 hour, taken out, and allowed to stand at room temperature for 24 hours. The plate is then tested according to the above test (2).
(4) Salt spray resistance: The coating is cut crosswise with a knife to the substrate surface. Then, the plate is subjected to a salt spray test in accordance with JIS Z2371 to measure the time until the largest bubble or the largest creep deformation on one side of the cross-cut has developed a width of 3 mm.
(5) Impact resistance: The test is carried out at 20 ° C in accordance with JIS K5400-1979 6.13.3 Method B. In this case, an impact tool of 0.5 in diameter and an anvil on an impact resistance tester, which is mounted horizontally on a concrete slab attached. The test plate is then placed in a position between the impact tool and the anvil. A 500 g weight is dropped onto the top of the impact tool from various heights up to 50 cm above the impact tool to determine the maximum fall height that does not cause cracking or peeling on the coating. The impact is applied to the plate on the coated front surface (forming a depression) and also on its back surface (forming a projection on the coated side).
(6) Scattering Power: The test coating composition is poured into a corrosion-resistant cylinder to a height of 27 cm from the bottom and uniformly stirred at 28 ± 1 ° C. An inner plate (15 × 300 × 0.4 mm) is fixed on the inside of a corrosion-resistant tube (16 mm inner diameter, 1 mm wall thickness, 300 mm length). The pipe is then mounted vertically in the corrosion-resistant cylinder at a distance of 20 mm from the ground. The internal plate is then applied with a voltage rising from 0 to 200 V within 10 seconds (the rate of increase is set so that it does not take minutes) and then switched off. The inner plate and the tube are washed with water. Then the inner plate is fired and dried. Subsequently, the extent to which the coating composition is deposited on the inner plate is measured. The larger the value, the better the scattering power.
(7) Bath stability: 1 liter of the electrophoretic bath is stirred for two months at 30 ° C and then filtered through a 400-mesh wire screen (mesh aperture 0.037 mm). The residue is dried at 120.degree. C. for 1 hour. Stability is reported as the weight (mg / ml of bath) of the residue obtained.

In each case two zinc phosphate treated plates are coated electrophoretically with the coating compositions obtained in Example 11 and Comparative Example 5. One of the plates is fired at 140 ° C for 20 minutes and the other at 180 ° C for 20 minutes. The degree of yellowing is determined by the naked eye. Even the Δ b value is determined. "Δ b" means a difference of a chromatic index b in the Hunter's equation. The surface color of the coated plate resulting after firing at 140 ° C for 20 minutes according to Example 11 is used as a standard. The value b is calculated from the basis of the chromaticity coordinates X, Y and Z of the CIE standard colorimetric system according to JIS Z 8722 using a standard illumination source C from the following equation:
b = 7.0 (Y-0.947Z) / (Y) 1/2

The test results are summarized in Table IV.

Table IV

Claims (19)

1. Cationic, electrophoretic coating compositions containing

• (I) a water-soluble to water-dispersible resin having primary or secondary hydroxyl groups, tertiary amino groups and an isocyanate-adduct having an α , β- unsaturated carbonyl group of the formula I. in which R₁ is a hydrogen atom or a methyl group and Y is one of the radicals where n is an integer of 1 to 4, 1 is 0 or 1, m is an integer of 0 to 20, R₂ is a hydrogen atom or a hydrocarbon group of 1 to 4 carbon atoms, and A is a divalent hydrocarbon group 1 to 20 carbon atoms; and
• (II) at least one curing catalyst selected from the group consisting of metal hydroxides, metal salts of organic acids, quaternary ammonium bases, quaternary ammonium salts of organic acids, quaternary phosphonium bases, quaternary phosphonium salts of organic acids, tertiary sulfonium bases, tertiary sulfonium salts of organic acids and alkali metal alkoxides.

2. Cationic, electrophoretic coating compositions containing a water-soluble to water-dispersible resin, which contains the following constituents: an isocyanate-adduktest with an α , β- unsaturated carbonyl group of the formula I. in which R₁ is a hydrogen atom or a methyl group and Y is one of the radicals where n is an integer of 1 to 4, 1 is 0 or 1, m is an integer of 0 to 20, R₂ is a hydrogen atom or a hydrocarbon group of 1 to 4 carbon atoms, and A is a divalent hydrocarbon group 1 to 20 carbon atoms, primary or secondary hydroxyl groups and at least one onium salt of an organic acid from the group of quaternary ammonium salts of organic acids, quaternary phosphonium salts of organic acids and tertiary sulfonium salts of organic acids. 3. Cationic, electrophoretic coating compositions containing

• (I) a mixture of a resin having primary or secondary hydroxyl groups, and a resin having an isocyanate adduct having an α , β- unsaturated carbonyl group of the formula in the R₁ is a hydrogen atom or a methyl group and Y is one of the radicals where n is an integer from 1 to 4, 1 is 0 or 1, m is an integer from 0 to 20, R₂ is a hydrogen atom or a hydrocarbon radical having 1 to 4 carbon atoms, and A is a divalent hydrocarbon radical having 1 to 10 carbon atoms, wherein at least one of the resins of the mixture contains tertiary amino groups in an amount sufficient to render the mixture soluble or dispersible in water when neutralized, and
• (II) at least one curing catalyst selected from the group consisting of metal hydroxides, metal salts of organic acids, quaternary ammonium bases, quaternary ammonium salts of organic acids, quaternary phosphonium bases, quaternary phosphonium salts of organic acids, tertiary sulfonium bases, tertiary sulfonium salts of organic acids and alkali metal alkoxides.

4. Cationic, electrophoretic coating compositions containing a mixture of a resin having primary or secondary hydroxyl groups and a resin with an isocyanate adduct having an α , b- unsaturated carbonyl group of the formula in which R₁ is a hydrogen atom or a methyl group and Y is one of the radicals where n is an integer of 1 to 4, 1 is 0 or 1, m is an integer of 0 to 20, R₂ is a hydrogen atom or a hydrocarbon group of 1 to 4 carbon atoms, and A is a divalent hydrocarbon group 1 to 10 carbon atoms, wherein at least one of the resins of the mixture contains at least one organic acid salt of quaternary ammonium organic acids, organic acid quaternary phosphonium salt and organic acid tertiary sulfonium salt in an amount sufficient to dissolve the mixture in water to make soluble or dispersible. 5. Compositions according to claim 1, characterized in that the water-soluble to water-dispersible resin on average at least 1.0 radicals of the formula I in the molecule, average at least 1.0 hydroxyl groups in the Molecule and 0.5 to 3.0 mol / kg (resin) of tertiary amino  groups and a number average molecular weight of 500 to 100,000. 6. compositions according to claim 5, characterized in that the Resin averages 1.5 to 100 residues of the formula I in the Molecule and on average from 1.5 to 100 hydroxyl groups in the molecule and a number average molecular weight from 500 to 30,000. 7. compositions according to claim 2, characterized in that the water-soluble to water-dispersible resin on average at least 1.0 radicals of the formula I in the molecule, average at least 1.0 hydroxyl groups in the Molecule and 0.2 to 1.5 mol / kg (resin) of onium salt one organic acid and a number average molecular weight from 500 to 100,000. 8. Compositions according to claim 7, characterized in that the Resin averages 1.5 to 100 residues of the formula I in the Molecule and on average from 1.5 to 100 hydroxyl groups in the molecule and a number average molecular weight from 500 to 30,000. 9. Compositions according to claim 3 or 4, characterized that the resin containing the remainder of formula I average at least 1.0 residues in the molecule as well as a Number average molecular weight in the range of 500 to 100,000 and the hydroxyl-containing resin average at least 2.0 primary or secondary Hydroxyl groups in the molecule and a number average of the Molecular weight in the range of 500 to 100,000. 10. Compositions according to claim 9, characterized in that the the resin containing the remainder of formula I on average 1.5 to 100 residues in the molecule and a number average of the Molecular weight in the range of 500 to 30,000  and the hydroxyl-containing resin averages 2 up to 100 primary or secondary hydroxyl groups in the molecule and a number average molecular weight in the range from 500 to 30,000. 11. Compositions according to claim 3, characterized in that the Resin mixture tertiary amino groups in an amount of 0.5 to 3.0 moles per kg of the resin mixture. 12. Compositions according to claim 4, characterized in that the Mixture of the resin with a content of radicals of the formula I. and from the hydroxyl group-containing resin Onium salt of the organic acid in an amount of 0.2 to 1.5 moles per kg of the mixture. 13. Compositions according to claim 3 or 4, characterized that the molar ratio of residual / hydroxyl groups of the mixture from the resin containing a content of the formula I and the resin containing primary or secondary Hydroxyl groups in the range of 10/1 to 1/20 lies. 14. Compositions according to claim 13, characterized in that the Molar ratio of residual / hydroxyl groups in the range of 5/1 to 1/10 lies. 15. Compositions according to claim 1 or 3, characterized the amount of curing catalyst is from 0.001 to 20 Parts by weight per 100 parts by weight of the resin solids. 16. Compositions according to claim 1 or 3, characterized that the amount of the curing catalyst is in the range of 0.1 to 10 parts by weight per 100 parts by weight of resin solids lies.   17. Compositions according to one of claims 1 to 4, characterized that Y in the formula I means -NHCH₂- Has. 18. Electrophoretic coating method, characterized that an article electrophoretically with coated according to any one of claims 1 to 4 with the article serving as a cathode. 19. Coated articles obtained by the method of claim 18.