DE3109282A1 - CATIONICALLY ELECTROPHORETICALLY DEPOSITABLE RESIN WITH BLOCKED ISOCYANATE GROUPS OF THE HARDENED TYPE - Google Patents

Description

- 10 description

The invention relates to a new, cationically electrically or electrophoretically depositable resin composition. The invention relates in particular to a cationically electrodepositable or electrodepositable resin composition having cured type blocked isocyanate groups containing a resinous product as a main component the one compound component with a primary amino group or with several primary amino groups, which by a carbonyl compound is or are blocked into one containing an isocyanate-reactive functional group Compound has been introduced through a diisocyanate compound component.

Various cationically electrodepositable resin compositions have already been proposed. E.g. in GB-PS 1 303 480 an electrophoretically depositable one Described composition which, dispersed in an aqueous medium, contains film-forming resin particles which contain an amino group containing addition polymer or a polycondensation product (including an amino group containing polyamide resin) and a blocked isocyanate (a so-called completely blocked isocyanate which practically all isocyanate groups are blocked). The electrophoretically deposited from this mass However, film cannot be considered satisfactory in terms of its corrosion resistance. To improve the corrosion resistance is therefore in this patent, the addition of up to 50 wt.% Of a Polyepoxy resin, based on the total weight of the mass, suggested. Even so, as far as the film properties are concerned, this product is not considered to be satisfactory to call.

A composition analogous to the above-mentioned electrophoretically depositable composition is mentioned in US Pat. No. 3,799,854, in US Pat. No. 3,799,854 a galvanic process is described in which a An aqueous bath made of a mass containing a soluble polyamine resin (essentially an amino group containing polyamide resin) and a blocked polyisocyanate. This electrophoretically separable mass however, has almost the same properties as that GB-PS 1 303 480.

It is also known that cured polyepoxides such as bisphenol A-epichlorohydrin type epoxy resin are excellent Have corrosion resistance and adhesion. It is also known to adducts of an epoxy resin and to solubilize a primary or secondary amine water by neutralization with acids. One electrophoretically Deposable coating compound in which such properties of the epoxies and adducts mentioned are used is described in U.S. Patent 3,984,299. In the case of the aqueous, electrophoretically depositable one described there The mass is a mixture of the epoxy resin-amine adduct mentioned and a blocked polyisocyanate. The coating obtained by the electrophoretic deposition of this mass has an excellent one Corrosion resistance, however, is in no way related due to the lack of the plasticizing component surface smoothness and bath stability (i.e. in terms of properties such as the ability to To maintain the conditions of the coated surface, the thickness of the deposited film and the coating behavior within the intended range at the time the continuous, electrophoretic coating without changes and, in particular, deterioration be effected) is satisfactory. Furthermore is at. the coating of objects with complicated

th forms the scattering power is not sufficient. Thus, this mass is in no way satisfactory in practice.

On the other hand, US Pat. No. 3,922,253 discloses a self-curable, electrophoretically depositable, aqueous coating composition described which an epoxy resin, a primary and / or secondary amine and a partially blocked Contains polyisocyanate. This mass can be considered an improved type of that described in US Pat. No. 3,984,299 but it can hardly be said that this mass is in terms of surface smoothness, flexibility, the bath stability, the scattering power and the like. Is completely improved. Accordingly, this mass is also for the technical Use not entirely satisfactory. With regard to the film-forming properties, there is no great one Difference from the product according to US Pat. No. 3,984,299.

A mass analogous to that of US Pat. No. 3,922 is described in US Pat. No. 3,947,339. It acts it is an electrophoretically separable, aqueous mass containing an acid-neutralized amino group Includes resin obtained by treating an epoxy group-containing resin with polyamine derivatives has been implemented, which has at least one primary amino and secondary amino group, through ketimine groups are blocked, with the further addition of a partially blocked polyisocyanate is provided. There it is expressed that with this aqueous mass it is in principle possible, a resin dispersion in Produce water with a low degree of neutralization, which in terms of the pH value of the bath mass and the scattering power shows some improvement. It is also said that there is a significant improvement in terms of the curability of the coating as a result of increased

Activity of the blocked isocyanate groups can be achieved. With this mass, however, it is very difficult to find the Reaction between the epoxy group-containing resin and the secondary amino groups in the aforesaid ketiminated Carry out polyamine derivative. In practice you have to such disadvantages are accepted as the fact that the polyamine derivative is not reacted in the aqueous mass remains or that the viscosity increases significantly when the reaction is forcibly completed. It is therefore almost impossible to fully obtain the above improvements.

To improve the deficiencies of the masses described above, US Pat. No. 4,036,795 discloses an electrophoretically depositable, proposed a cationic resin composition obtained by using an amine-adducted epoxy resin is mixed or reacted with a polyamide resin containing amino groups and that continues with it partially blocked polyisocyanate is implemented. Farther are disclosed in U.S. Patents 4,134,866 and 4,134,865 Electrophoretically depositable, cationic resin compositions described, the main component of which is a mixture of one Reaction product of at least two components of a reaction product of an epoxy resin and a basic one Amino compound, a basic, amino group-containing polyamide resin and a partially blocked isocyanate contain. The remaining component of the electrodepositable coating composition contains similar ones Constituent components such as the compositions of US Pat. No. 4,036,795. Furthermore, US Pat. No. 4,190,564 mixing the amine-adducted epoxy resin fatty acid composition or a resin composition system containing an amino group containing polyamide resin and a partially blocked polyisocyanate, with a polyether with special Properties described, making the surface smoothness

of the film is greatly improved without affecting the corrosion resistance is worsened.

The market requirements for the properties of an electrophoretically However, the separable resin composition has recently become more and more stringent. The invention is therefore the object based on improving the properties of an electrophoretically depositable, cationic resin composition. According to the invention it was found that resinous products with a sufficient amount of primary amino groups can be obtained more easily by linking a compound blocked by a carbonyl compound primary amino groups and isocyanate-reactive functional groups (primary or secondary amino groups or hydroxyl groups) contains, with a compound that has at least two isocyanate-reactive functional groups (primary or secondary amino groups or hydroxyl groups), caused by a diisocyanate compound. It was determined, that the resinous product thus formed is not only excellent in properties in terms of pH of the bath, the scattering power, the hardenability and the like. But is also capable of providing a coating with excellent Adhesion, flexibility, impact resistance and the like.

The invention therefore relates to a cationic, electrophoretic or electrically or electrodeposable resin composition which has been obtained by (I) (A) a compound which has at least two isocyanate-reactive functional groups in one molecule of active hydrogen-containing amino groups and hydroxyl groups (hereinafter referred to as "compound A "denotes),

(B) a compound that contains in a molecule at least one primary amino group, represented by a carbonyl group is blocked, and at least one isocyanate reaction

tive, functional group selected from active hydrogen containing amino groups and hydroxyl groups (hereinafter referred to as "Compound B"), and

(C) a diisocyanate compound that is in one molecule contains two free isocyanate groups (hereinafter referred to as "Compound C"),

implement with each other and that one
(II) the above reaction mixture with

(D) a partially or completely blocked polyisocyanate compound which in one molecule at least two isocyanate groups, one or more of which is or are blocked, and no longer one as a free isocyanate group contains (hereinafter referred to as "Compound D")

converts, the mass containing as the main component a resinous product, in which the component of the compound B with the blocked primary amino group (η) in the component of the compound A has been introduced through the component of the diisocyanate compound C.

According to the invention, primary amino groups are incorporated into the resin base component by a urea bond or urethane bond formation reaction between compound C, e.g., the diisocyanate compound, and the active hydrogen containing amino group or hydroxyl group. It is therefore made possible to use a sufficient amount of to introduce primary amino groups even into a resin base component which does not contain an epoxy group. This will be not only various limitations or disadvantages of using epoxy group-containing resins according to overcome the prior art, but also an electrophoretically depositable resin mass is obtained, compared to a conventional resin composition with a resin containing epoxy groups as the base resin has better properties.

The resin composition of the present invention is described in detail below explained in more detail.

Connection A

The compound A is the main base resin component of the invention resinous product. It is a compound that contains at least two isocyanate-reactive, functional groups, namely amino groups and / or hydroxyl groups containing active hydrogen, contains. Either a primary amino group containing two active hydrogen atoms or a secondary amino group, which contains an active hydrogen atom is sufficient for the said active hydrogen-containing amino group, but in general the secondary amino group is more preferred because it has mild reactivity to the isocyanate group. On the other hand it is The reactivity of a hydroxyl group towards the isocyanate group is highest when it is attached to the primary carbon atom is attached while at a hydroxyl group attached to a secondary carbon atom, and of a hydroxyl group attached to a tertiary carbon atom, the reactivity decreases in that order. The hydroxyl group should therefore preferably be attached to the primary carbon atom, but it does play the presence of a hydroxyl group attached to the secondary carbon atom or a tertiary carbon atom is attached, of course, does not matter.

The compound A can contain at least two such isocyanate-reactive functional groups in one molecule. Although the preferred number of functional groups depends on the kind of functional group, molecular weight of Compound A and the like varies, it is generally preferred that Compound A have an average of 2 up to 10 isocyanate-reactive functional groups per molecule

contains. Furthermore, the compound A should preferably have the isocyanate-reactive functional groups in the range from 100 to 2000, more preferably from 200 to 1000, in terms of the equivalent number of isocyanate-reactive functional groups Groups, included. A variety of isocyanate-reactive functional groups found in compound A can be the same or different from each other.

The "equivalent number of isocyanate-reactive, functional Groups "means the number or amount, expressed in grams, of isocyanate-reactive functional groups Compound / g-equiv. the isocyanate-reactive functional group.

The compound A can also have a functional group or functional groups with lower reactivity towards Contain isocyanate, e.g. an acid amide bond, ester bond, ether bond, urethane bond, urea bond, Allophanate binding and biuret binding. In general, however, it is preferred that functional groups, capable of reacting with an active hydrogen-containing amino group or hydroxyl group, e.g. an epoxy group, are practically absent. That is, the compound A should preferably be epoxy-free Be connection.

As long as at least two of the mentioned isocyanate-reactive functional groups are contained in one molecule, either low molecular weight compounds or high molecular weight compounds (i.e. polymeric compounds) for compound A. Furthermore, aliphatic type compounds are also as well those of the aromatic type (including araliphatic type compounds) are suitable. In terms of

However, the corrosion resistance of the coating is generally considered to be aromatic type compounds (in the case of Polymers, those in which the main chain is mainly formed from aromatic rings) are preferred. In general Compound A should preferably have a number average molecular weight of about 100 to about 10,000, preferably about 200 to about 5000.

The following are examples of representative compounds which can be used as Compound A for the purposes of present invention are suitable.

(I) Adducts of an epoxy resin and a diamine with two amino groups (primary or secondary amino groups) containing at least one active hydrogen atom, or adducts of an epoxy resin and an amine compound which have two or more active hydrogen atoms in one molecule contain, e.g. a primary or secondary amine containing hydroxyl groups:

As the epoxy resins for forming this adduct, there are, for example, aromatic type epoxy resins such as epoxy resin Bisphenol type made by reacting bisphenol A or bisphenol F and epihalohydrin is suitable. Such epoxy resins can usually have a number average molecular weight of from about 300 to about 4,000, preferably from about 400 to about 3000. Generally they have an epoxy equivalent of from about 150 to about 4000, preferably about 200 to about 2000. The following products can be found as specific examples of such epoxy resins from Bisphenol type are called.

Epoxy resins manufactured by Shell Chemical Co., Ltd., Japan:

Epikote 828 (bisphenol Α-type, number-average epoxy equivalent

Molecular weight valence about 380 about 190)

"1001 (" "900" 475)

η ₁₀ 04 "" 1400 "950)

H 1007 ("" 2900 "1900)"

Epoxy resins manufactured by Dainippon Ink & Chemicals Ine., Japan:

Epiclon 830 (bisphenol F-type about 360 about 180).

Amines capable of being adducted with these epoxy resins can be prepared from compounds with the following Structural formulas:

R »-NH ₂ , H ₂ NR ₁ -NH ₂ , H ₂ NR ₁ -NHR ^f , H ₃ NR ₁ -NR» R ", R ¹ HN-R ₁ -NHR", HO-R ₁ -NH ₂ and HO-R ₁ -NHR ¹ where R _{1 stands} for an alkylene group, cycloalkylene group, arylene group or aralkylene group, R ¹ and R ″ stand for an alkyl group, cycloalkyl group, aryl group or aralkyl group.

Also heterocyclic compounds that have 1 or 2 N atoms included are suitable. Individual examples are primary monoamines, such as alkylamines, e.g. ethylamine, propylamine and butylamine, cyclohexylamine, aniline and benzylamine; Diamines, e.g. ethylenediamine, Ν, Ν-dimethylethylenediamine, piperazine and m-phenylenediamine. Primary or secondary amines containing hydroxyl groups are, for example, primary or secondary Lower alkanolamines, such as monoethanolamine, diethanolamine, N-methylethanolamine and N-hydroxyethylpiperazine, suitable.

The addition reaction of these amines with the epoxy resins should preferably be carried out until the epoxy groups in which the epoxy resin is substantially completely consumed.

(II) Adducts of epoxy resins and water or polyhydric alcohols:

As epoxy resins for forming these adducts, the adducts mentioned under (I) above are preferred. Examples for polyhydric alcohols added to the epoxy resins are lower alkylene glycols such as ethylene glycol and Propylene glycol; Glycerine, trimethylol propane; Poly (lower alkylene glycols), such as diethylene glycol and triethylene glycol. The addition reaction of the epoxy resin with the water or the polyhydric alcohols should preferably be carried out until the epoxy groups are substantially are completely used up.

(III) Diphenol compounds or bisphenol compounds, such as bisphenol A, bisphenol F (4,4 ^f -dihydroxydiphenyl methane), dihydroxydiphenylethane, 4,4 ^f -hydroxyphenylisobutane, 4,4'-dihydroxybenzophenone and 1,5-dihydroxynaphthylene.

(IV) Phenol-terminated prepolymers formed by addition polymerization reaction of bisphenol compounds and diepoxy compounds or diisocyanate compounds:

As examples of diepoxy compounds to form such Prepolymers can diglycidyl ethers of the bisphenol compounds mentioned (examples: Epikote 827, a product of Shell Chemical Co., Ltd., Japan; Araldite GY-250, a product of Ciba Geigy AG; DER-330 »a product of the Dow Chemical Company, etc.), diglycidyl ethers of polyalkylene glycols (Examples: Epikote 812, a product of Shell Chemical Co., Ltd., Japan; K-425, a product of Asahi Ciba Company, Japan, etc.), vinylcyclohexene dioxide (Examples: Chissonox 206, a product of Chisso Co., Ltd., Japan) and the like. As diisocyanate compounds are those products that are related below with compound C are preferred.

(V) Addition-polymerized prepolymers of bispheno! Compounds and alkylene oxides:

Examples of alkylene oxides for forming such prepolymers are ethylene oxide, propylene oxide and the like.

(VI) Copolymerized styrene-allyl alcohol prepolymers:

Examples of such copolymerized prepolymers are those having an average molecular weight of 3,000 or less, specific examples of such prepolymers are RJ-101 (number average molecular weight of about 1700, hydroxyl group equivalent about 220) and RJ-100 (number average molecular weight of about 2300, hydroxyl group equivalent of about 300), products of Monsanto Chemical Company.

(VII) Polycondensed prepolymers of aromatic dicarboxylic acids and diamines, alkanolamines or Polyols:

The aromatic dicarboxylic acids that can be used are which are usually used for the production of polyamides or polyesters. Examples are phthalic acid, Isophthalic acid, terephthalic acid and the like. Further, as diamines to be reacted therewith, e.g. Ethylenediamine, hexamethylenediamine, m-phenylenediamine and The like., can be used. As alkanolamines, e.g. monoethanolamine, diethanolamine, triethanolamine, hydroxyethylpiperazine and the like, and as polyols, for example, ethylene glycol, propylene glycol, glycerin, 2,2-dimethylpropanediol, trimethylolpropane and the like.

The polycondensation reaction of the aromatic dicarboxylic acid and the diamines, alkanolamines or diols can be produced according to the known polyamide or polyester formation reaction be performed.

I UJZ _- Ui

(VIII) Novolak-type phenol-formaldehyde resins:

In general, these resins should preferably have a number average Have molecular weights of about 1000 or less.

(IX) Aromatic di- (primary amines):

Suitable examples include m-phenylenediamine, 4,4-methylenedianiline ^f, benzidine, 2,4-tolylene diamine, diaminodiphenyl ether, 4,4'-thiodianiline, diaminodiphenyl sulfone, dianisidine, and the like.

(X) Prepolymers terminated with primary amines formed by addition polymerization reaction of aromatic Di- (primary amine) and dicarboxylic acids, diepoxy compounds or diisocyanate compounds:

The above products can be used as aromatic di- (primary amine) and diepoxy compounds or diisocyanate compounds, used to form these prepolymers. As dicarboxylic acids e.g. aliphatic, dibasic acids such as adipic acid, sebacic acid, dimerized linoleic acid and the like can be mentioned.

(XI) Compounds containing hydroxyl groups

of the aliphatic type (including the alicyclic type):

As examples, adducts of epoxy groups can be used Prepolymers such as hydrogenated bisphenol type epoxy resins, polypropylene diglycidyl ether and epoxidized polybutadiene with aliphatic mono- (primary amines) or alkanolamines, prepolymers containing hydroxyl groups., such as Polypropylene glycol, polytetraethylene glycol, polycaprolactone diol and polybutadiene glycol, and the like.

Of the abovementioned compounds, in particular the compounds listed under (I), (II), (IV) and (VI) are as Compound A suitable. Adducts of epoxy resins of the bisphenol Α type and alkanol

amines; phenol-terminated prepolymers of bisphenol A. and diisocyanates; and copolymerized styrene-allyl alcohol prepolymers suitable.

The above compounds can be used either singly or in combination in two or more.

Connection B

The compound B used in the present invention is a compound which has at least one primary in a molecule Amino group blocked by a carbonyl compound is, and at least one isocyanate-reactive, functional Group, namely an active hydrogen-containing amino group and / or a hydroxyl group. This connection is a component that is required to convert strongly basic, primary amino groups into the inventive To introduce resin product. The "primary amino group blocked by a carbonyl compound" is a protected one Amino group that can be converted into a free primary amino group by a simple process, e.g. hydrolysis is. Typically it is a temporarily protected, primary amino group of the general formula

in the Rp for a hydrogen atom or a monovalent one Hydrocarbon group of 1 to 6 carbon atoms, e.g. an alkyl group or a cycloalkyl group, R-, for a monovalent hydrocarbon group having 1 to 6 carbon atoms, e.g. an alkyl group or a cycloalkyl group, or where Rp and R ^ together represent a Alkylene group with up to 9 carbon atoms.

OIUO L U L

The said amino groups and hydroxyl groups containing active hydrogen are isocyanate-reactive, functional Groups required to connect compound B to compound A through compound C (diisocyanate compound), as described below, and they can have the same properties as previously described in connection with compound A. As active hydrogen containing amino groups or Hydroxyl groups, secondary amino groups or primary hydroxyl groups are particularly preferred.

The compound B includes, for example, the following compounds: (a) polyamine compounds containing a primary amino group together with a secondary amino group; (b) hydroxyl group-containing amine compounds which contain a primary amino group together with a hydroxyl group; and (c) a hydroxyl group-containing polyamine compound containing three components of a primary amino group, a secondary amino group and a hydroxyl group, these compounds (a), (b) and (c) being generally referred to hereinafter as ^M (poly) amine compounds " where at least a portion of the primary amino groups present, preferably substantially all of the primary amino groups present, are blocked by carbonyl compounds Compound B can be used.

Of the (poly) amine compounds mentioned, there are both those with a low molecular weight and those with a high molecular weight Molecular weight as well as those of the aliphatic type (including the alicyclic type) and the aromatic type

suitable. In general, however, (poly) amine compounds of the aliphatic type are more preferred.

As stated above, the compound B is a necessary component for the water solubilization to which the Acid neutralization of the resin mass follows by adding strongly basic, primary amino groups to the invention resinous product are introduced. The (poly) amine compounds mentioned should advantageously generally have an equivalent of primary amino groups in the range of about 2000 or less, preferably about 1000 or less, and the equivalent of the isocyanate-reactive, functional groups should generally preferably be in the range of about 2000 or less, more preferably around 1000 or less, fall.

Furthermore, the (poly) amine compounds should generally favorably have a number average molecular weight of about 5000 or less, preferably about 3000 or less.

The (poly) amine compounds preferred for the purpose of the present invention are represented by the following general formulas given:

5 - 26th 11 " ^NH 2 (5) H ₂ N ₊ R ₄ -NH ^ -R (1) H ₂ N ₊ R ₆ -NHVS ₆ -OH ! ⁽²⁾ H ₉ N ₊ R ₇ -NH -) - R _Q
^ l Co (3) H N-R'-N-R'-NH (30 R 'RtI
«5 R ₅ «NT * H ₂ ONLY ₉ -NH ^ H ₂ NR ₁₃ -OH

(4)

H (6) j

where R ^, Rg, Ry, Rq, R 'y, R' q »Rg» R ₁ q »R ₁ -jt R ₁ ^ u ¹¹ ^ - R ₁ 4 each for an alkylene group (preferably a lower alkylene group with up to 6 carbon atoms) or a cycloalkylene group, preferably a cycloalkylene group with up to 9 carbon atoms; R ^, R ¹ ^, R "^ and R-ip each represent an alkyl group (preferably a lower alkyl group of up to 6 carbon atoms) or a cycloalkyl group (preferably a cycloalkyl group of up to 9 carbon atoms); and a, b, c , d and e are each an integer of 1 or more, and particularly an integer of 1 to 5.

Specific examples of these (poly) amine compounds are the following compounds.

(a) N-Alkylalkylenediamines H ₂ N-CH ₂ -CH ₂ -NH-CH ₃ , H ₂ N-CH ₂ -CH ₂ -CH ₂ -NH-CH ₃ , H ₂ N-CH-CH ₂ -NH- CH ₃ . '

- 27 - (b) Polyalkylenepolyamines

H ₂ N-Ch ₂ -CH ₂ -NH-CH ₂ -CH ₂ -NH ₂ , H ₂ N-CH ₂ -CH ₂ -NH-CH ₂ -CH ₂ -NH-Ch ₂ -CH ₂ -NH ₂ , H ₂ N-CH ₂ -CH ₂ -NH-CH ₂ -CH ₂ -NH-CH ₂ -CH ₂ -NH-CH ₂ -Ch ₂ -NH ₂ ,

H ₂ N-CH ₂ -CH ₂ -NH-CH ₂ -CH ₂ -NH-Ch ₂ -CH ₂ -

. NH-CH ₂ -CH ₂ -NH-CH ₂ -Ch ₂ -NH _2,. .

H ₂ N-CH ₂ -CH ₂ -CH ₂ -NH-CH ₂ -CH ₂ -Ch ₂ -NH ₂ .

(c} N- (Hydroxyalkyl) -alkylenediamines H ₂ N-CH ₂ -CH ₂ -NH-CH ₂ -Ch ₂ -OH, H ₂ N-CH ₂ -CH ₂ -CH ₂ -NH-CH ₂ -CH ₂ -CH ₂ -Oh, H ₂ N-CH ₂ -CH ₂ -NH-CH ₂ -CH ₂ -CH ₂ -Oh.

(d) mono- (hydroxyalkyl) amines H ₂ N-CH ₂ -CH ₂ -OH,

H ₂ N-CH ₂ -CH ₂ -CH ₂ -OH,

H ₂ N-CH ₂ -CH-OH.
CH ₃

(e) N- (aminoalkyl) - piperazine

U XT ΓΊ1 OU Vi ^

^ NH

As (poly) amine compounds, in addition to the compounds listed above, it is also suitable with primary. Amino groups terminated prepolymers (polyamide polyamines), formed by a condensation reaction between aliphatic, polybasic acids such as adipic acid, sebacic acid, dimeric acids (dimerized linoleic acid), maleinized fatty acids (e.g. maleinized oleic acid, linoleic acid, linolenic acid, dehydrated ricinoleic acid or elaostearic acid) or polybutadiene-dicarboxylic acids and an alkylenediamine, such as ethylenediamine, propylenediamine, butylenediamine and hexamethylenediamine, or a polyalkylenepolyamine of the formula (2) can be used. Specific examples of such polyamide polyamines are e.g. the products Versamid 100, 115, 125, 140, etc. from Japan General Mills Co., Ltd., Japan.

Of the (poly) amine compounds listed above, monoethanolamine, monopropanolamine, monobutanolamine, diethylenetriamine are used or condensate of ι dimer acid and polyalkylenepolyamine particularly preferred, but the above can (Poly) amine compounds can be used alone or optionally in combination of two or more.

The (poly) amine compounds mentioned can be used as compound B after at least part of the primary amino groups present, preferably essentially all primary amino groups present, by carbonyl compounds have been blocked. Examples of carbonyl compounds used for this blocking are ketones and aldehydes, which are usually used to protect amino groups by ketiminization or Aldimination can be used. Specific examples of suitable ketones are acetone, methyl ethyl ketone, methyl isobutyl ketone, Diisobutyl ketone, cyclopentanone, cyclohexanone and the like. Specific examples of aldehydes are acetaldehyde, Propionaldehyde, benzaldehyde, pivaldehyde and the like.

The reaction of the (poly) amine compounds with these carbon compounds is carried out in a manner known per se [cf. e.g. J.Org.Chem., £ 1, 1054-76 (1954)]. at On this occasion, it is appropriate to employ such quantitative proportions and reaction conditions that substantially all, preferably greater than 8096, more preferred more than 9096, the primary amino groups themselves react with the carbonyl compounds. It is generally beneficial to use ketones with moderate water solubility! .ness and low steric hindrance, such as methyl isobutyl ketone, so that the reaction (the dehydration reaction) runs smoothly.

Compound C

The compound C, which mainly has the role of a crosslinking agent in the binding of the compound A to the compound B in the composition of the invention resinous product is a diisocyanate compound, which contains two free isocyanate groups in one molecule.

As such diisocyanate compounds, all types of diisocyanate compounds commonly used in the production can be used are used by polyurethanes, e.g. those of the aliphatic series (including the alicyclic Series, as mentioned above) and those of the aromatic series (including the aromatic-aliphatic series Series, as mentioned above), as well as diisocyanates by partially blocking triisocyanate and tetraisocyanate compounds with lower alcohols, and the like. In general, however, those having a molecular weight are used from about 100 to about 2000, preferably from about 150 to about 1000, preferably.

Such diisocyanate compounds are generally a group of compounds represented by the following formulas can be specified.

(1) Diisocyanate OCN-R ₁₅ -NCO

(2) monourethane from triisocyanate

R., - NCO, 1b NHCO-OR.

OCN-R ₁₅ -NCO (7)

OCN-R ₁₆ -NCO C

₁₇ (3) diurethane of tetraisocyanate

NHCO-OR _1g

OCN-R ₁₈ -NCO (9)

NHCO-OR ₂₀

wherein R ₁₅ , R ₁₆ and R ₁₈ each represent a monovalent, divalent or trivalent aliphatic (including an alicyclic) or aromatic hydrocarbon group or such a group which contains an ether bond, thioether bond, carbonyl group, sulfonyl group, urethane bond or urea bond or the like, stand; and R ₁₇ , R ₁ Q and R ₂₀ each represent an alkyl group, cycloalkyl group, or aryl group.

Specific examples of diisocyanate compounds are given below of the given general formulas.

₂ ^ = 2-12),

OCN-CH ₂ -CH ₂ -S-CH ₂ -Ch ₂ -NCO, OCN-CH ₂ -Ch-CH ₂ -CH ₂ -NCO ₁ OCN-CH ₂ -CH ₂ -CH ₂ -O-CH ₂ -CH ₂ -Ch ₂ -NCO,

OCH ₃ OCN-CH ₂ -CH ₂ -CH-CH ₂ -CH ₂ -Ch ₂ -NCO,

CH ₂ -NCO

CH ₂ -NCO (2-position or 3-position)

CHp-NCO

- 31 -

(2-position or Α-position)

CH ₉ -NCO

1 * CHp-NCO

CH ₂ -NCO CH ₂ -NCO

NCO
♦

NCO (3-position or

4- (Ibsition)

CH, NCO

NCO NCO

-NCO (Α-position or

5 position) j

OCN

NCO (6-position or 7-position)

NCO

OCN - // V-V V-NCO,

(2-position or A-position)

OCN-v '

CH

CH

O IUJ £ U £

OCN- / ΪΓΛ-CH ₂ - / iTS-NCO,

CH ₃ O 0CN - // _ \\ _ CH ₂

OCH ₃ -NCO,

M-CO- ^ M-NCO, lysine diisocyanate, Isophorone diisocyanate,

-CH-e M-NCO

NHCOOG

NCO

OCN

NHCOOG,

CH.

NCO

NHCOOG

GOOCHN

NHCOOG

NHCOOG

NCO

OCN

(g = 1, 2, 3)

C ₂ H

CH ₂ -0C0NH - (/ M-CH

OCONH - // ^ VCH

3
HCOOG

0CN4CH ₂ ^ NHC00-CH _p -C-CH _;> -0C0NH- _{1 w} " _o,,

^J 3 {h = 1, 2, 3)

-NC0

CH ₂ -OCONH- (CH ₂ ) ₆ -NHC00G

where G is a lower alkyl group, cycloalkyl group or Aryl group.

Furthermore, diisocyanates, obtained by adding these diisocyanates and diols, such as ethylene glycol and diethylene glycol, and monourethanes of triisocyanates obtained by adding the above-mentioned diisocyanates and triols, such as Glycerin and trimethylolpropane, and monoalcohols can be used.

OIU α L O L

These diisocyanate compounds can each be used for either can be used alone or in combination as two or more.

Of the diisocyanate compounds mentioned, examples of particularly suitable compounds C are the following compounds: 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4 ^I -diphenylmethane diisocyanate, 1,4-xylylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 1, 6-hexamethylene diisocyanate, isophorone diisocyanate, 2,4-tolylene diisocyanate adducts of ethylene glycol, diethylene glycol or propylene glycol, reaction products of 1 mole of 2,4-tolylene diisocyanate adducts of trimethylolpropane and 1 mole of lower aliphatic monoalcohols and the like.

Connection D

As compound D partially or completely blocked polyisocyanate compounds are used, which are in a molecule at least two isocyanate groups, at least one of which is blocked, and no more than one free isocyanate group contain.

The compound D is a component that acts as a crosslinking agent for crosslinking and curing the electrophoretically deposited film from the resin composition according to the invention is used during firing.

Polyisocyanate compounds of the aliphatic type as well as the aromatic type can be used for the preparation of the compound D can be used as long as 2 or more isocyanate groups are contained in the compound. In general their molecular weight falls in the range of 100 to 2000, preferably 150 to 1000. As such, polyisocyanate compounds can, for example, diisocyanate compounds of the formulas (7) to (9), which were previously

hang with compound C can be used.

The polyisocyanate compounds mentioned can be used as a compound D can be used after they have been blocked with a blocking agent until they fail on average contain more than one free isocyanate group in the molecule. The blocking reaction can be carried out by procedures known per se [cf. e.g. the procedure, described in Angew. Chem. J59, 257 (1947)]. Examples for blocking agents for the mentioned polyisocyanate compounds are active hydrogen-containing compounds, such as monofunctional alcohols, phenols, lactams, oximes, tertiary amino alcohols and the like. There will be such preferred which are capable of rapidly removing free isocyanate groups by heat dissociation at the firing temperature to regenerate. In general, volatile, active hydrogen containing low molecular weight compounds, preferably not more than 300, more preferably not more than 200, is used. Examples of this are the following materials: aliphatic or aromatic monoalcohols, such as methanol, ethanol, propanol, Isopropanol, n-butanol, tert-butanol, hexanol, cyclohexanol, Benzyl alcohol, ethylene glycol monoethyl ether (im Trade also referred to as "Cellosolve") and ethylene glycol monobutyl ether; tertiary hydroxyamines, such as dimethyl or diethylaminoethanol; Oximes such as acetoxime and methyl ethyl ketone oxime; active methylene compounds such as acetylacetone, acetoacetate ester and malonate ester; Lactams, such as £ - Caprolactam; Phenols such as phenol and cresol, and the like. Of these compounds, in terms of odor and toxicity during burning of the electrodeposited film, particularly aliphatic monoalcohols preferred.

ο ι υ α ζ. ο L

Partially blocked type compounds and fully blocked type compounds can be used as compounds D are, but they should preferably be present in a state in which the compound to the invention resinous product is bound. Accordingly, partially blocked compounds are more preferred.

Manufacture of the resinous product

The resinous product according to the invention can be produced in that the three components of the compound A, Compound B and compound C are reacted with one another in any order. In some cases it can can also be produced by reacting four components of these components plus compound D with one another (which is limited to the case that the reaction system contains a partially blocked polyisocyanate compound). The order of reactions between the reactances can vary according to the class or properties of the used Compounds A to D can be varied. For example, these can be selected from any of the following Reactions 1 to 10 are implemented. The person skilled in the art can take into account the choice of the mode of reaction the specific properties of compounds A to D (e.g. depending on whether it is a compound low molecular weight or high molecular weight) and the type of reactive Groups and the like on hand. In the description of the reaction modes given below, the Assumed that the compound D is also implemented with the other compounds. But when the fully blocked polyisocyanate compound is used as compound D, then it can be added to the reaction mixture or the reaction components at any stage of the reaction or after the reaction of compound A, Compound B and Compound C are given. Farther

can share the partially blocked polyisocyanate compound can be used with the fully blocked polyisocyanate compound. In this case, that could be partial blocked polyisocyanate compound are reacted according to the reaction mode described below and the fully blocked polyisocyanate compound could be admixed after or at any stage of the reaction will.

Reaction 1 ; A mixture of Compound C and Compound D is added to a mixture of Compound A and Compound B and then reacted therewith.

Reaction mode 2 : The compound A and the compound C and the compound B and the compound D are each reacted with each other, and the two kinds of reaction products obtained are mixed with each other and further reacted. It is also possible to proceed in such a way that the compound A and the compound D and the compound B and the compound C are each reacted with one another and the two types of reaction products obtained are mixed with one another and reacted further.

Reaction mode 3 i The compound A is reacted with a mixture of the compound C and the compound D and then further reacted with the compound B.

Reaction 4 ; The compound A is reacted with the compound C. The reaction product obtained is reacted with the compound D and then with the compound B. It is also possible to proceed in such a way that the compound A is reacted with the compound D and the reaction product obtained is reacted with the compound C and then with the compound B.

Reaction 5 ; The compound A is reacted with the compound C, and the obtained reaction product is reacted with the compound B and finally with the compound D.

IUO Z. U JU

Reaction 6 ; The compound A is reacted with the compound D. The obtained reaction product is mixed into the compound B and then reacted with the compound C.

Reaction 7 : The compound B is reacted with the compound C. The reaction product obtained is reacted with the compound A and then with the compound D.

Reaction 8 ; The compound B is reacted with a mixture of the compound C and the compound D. The reaction product obtained is then reacted with the compound A.

Reaction 9 sec. The compound B is reacted with the compound D, and the obtained reaction product is mixed into the compound A and then reacted with the compound C.

Reaction 10 ; The compound B is reacted with the compound C, and the obtained reaction product is mixed into the compound D and then reacted with the compound A.

In the reaction modes described above, the term “reaction product ¹¹ ” is intended to include not only the quantitative reaction product of the reaction components mentioned, but also unconverted reaction components and / or partially converted product of the three reaction components.

In the above-mentioned modes of reaction, it is in the case that the compound A or the compound B with the compound D is reacted with the compound C before the reaction, it is important that the reaction ratio and / or the reaction conditions of the compound D with respect to the compound A or the compound B is controlled in such a manner be that not all isocyanate-reactive, functional

3109? Π2

Groups in compound A or compound B themselves with connection D.

To obtain as far as possible a bond of the compound A and the compound B through the compound C should the reactivities of the isocyanate-reactive, functional Groups in the compound A and the compound B are expediently set the same or the reaction process should expediently be carried out in such a way that one compound is first connected to compound C is implemented and that the other compound is then implemented or the like.

The reaction of the compounds A to D according to the reaction modes mentioned can be carried out by a procedure suitable for the urea bond formation reaction between an active hydrogen-containing amino group and the isocyanate group and for the urea bond formation reaction between the hydroxyl group and the isocyanate group is well known. For example the reaction at relatively low temperatures, preferably in the range of about 0 to about 120 C, and in one essentially anhydrous solvent which is inert towards the isocyanate group, carried out with stirring Ensure that the reaction proceeds as uniformly as possible. Suitable solvents are e.g., aromatic hydrocarbons such as toluene and xylene; Ketones such as methyl ethyl ketone and isophorone; Ether, like dioxane and ethylene glycol dimethyl ether; tertiary alcohols, such as t-butanol and diacetone alcohol. Furthermore, if necessary also secondary alcohols, such as isopropanol and propylene glycol monomethyl ether, which have a relatively low level Having activity against an isocyanate group can be used. Of these solvents should be hydrophobic solvents be used in such an area that

does not affect the water dispersibility of the resin formed will. Regardless of which solvent is used, it should usually be in an amount of 60 parts by weight or less based on 100 parts by weight of resin solids, are used so that the high scattering power of the resin composition formed is not impaired.

Although the material proportions required for the connection A, connection B, connection C and connection D differ from type to type of these connections, can be the first As a guideline, the following proportions should be specified.

Compound A: In view of the corrosion resistance of the resinous product, this compound should expediently in an amount of 30 to 80% by weight, preferably 40 to 70 wt. 96, based on the total amount of compounds A to D are used.

Compound B: In view of the water dispersibility of the resinous product, this compound should are advantageously used in proportions such that one equivalent of the primary amino groups of 300 to 3000, preferably 500: i> is 2500, is reached.

Compound C: This connection should be expedient be used in an amount close to 1 mole / mole of Compound B as an amount necessary to be introduced upon introduction the compound B into the compound A to obtain water dispersibility. Naturally, this connection can also be present individually. If the compound is of high molecular weight, then compound C can be used in an amount of not more than 1 mole / mole of Compound B. If in addition to the reaction of compound B and compound C is expected to react between compound A and compound C, then compound C be present in an amount greater than 1 mole per mole of compound B.

Compound D: In view of the curability of the resinous product, this compound should be appropriate used in proportions such that one equivalent of the blocked isocyanate groups (i.e. Molecular weight / number of blocked isocyanate groups introduced into the molecule) from 400 to 4000, preferably 600 to 3000, of the resinous product is reached.

In the above-mentioned modes of reaction, the following reactions mainly take place:

(1) a crosslinking reaction between the component of the compound A and the component of the compound B, wherein compound C acts as a crosslinking member;

(2) a polymerization reaction between compounds A and C;

(3) a polymerization reaction between compounds B and C;

(4) a blocked isocyanate inducing reaction between the component of the compound A and the compound D; and

(5) a blocked isocyanate inducing reaction between the component of the compound B and the compound D, as a result of which two or more of these reactions are combined to give the to form resinous product.

The constituent components of the resinous product thus formed may have any of the structures shown below to have.

ACB ₁ A- (CB) _n -CA (n> 1),

ACA ₁ A- (CA) _n -CA (n> 1),

BCB, B- (CB) _n -CB (n> I) ₁

ACBD ₁ DACBD ₁

A-C-A-D, D-A-C-A-D,

B-C-B-D, D-B-C-B-D, j

AD, BD, A, B, D. ''

Furthermore, the resinous product of the present invention should preferably have the following properties:

Equivalent of the primary amino groups: about 300 to about 3000, especially about 500 to about 2500;

Equivalent of blocked isocyanate groups: about 400 to about 4000, especially about 600 to about 3000;

Ratio of the equivalent of the remaining isocyanate-reactive functional groups (including of primary amino groups) to the equivalent of blocked isocyanate groups: about 0.5 to about 4.0.

Since the resinous product of the present invention in the molecule contains strong basic, primary amino groups, which are blocked by carbonyl compounds, in a sufficient amount, that the resinous product is water-solubilized or water-dispersed by neutralizing it with an acid and since it still contains blocked isocyanate groups, the hardening of the coating film after effecting the electrodeposition, it can be effective as a film-forming component in electrophoretic separable, cationic resin compositions are used.

Production of the electrophoretically separable, cationic resin composition

In the preparation of the electrodepositable, cationic resin composition according to the invention using the Resin-like product according to the invention can this in a simple manner as a clear, electrophoretically depositable mass be used. In general, however, it can be advantageous can be used as a pigmented, electrodepositable mass by incorporating pigments and other conventional additives. As to be added Pigments can be used those that are formulated in a conventional manner, electrodepositable Paint compounds are incorporated. For example, color pigments such as red iron oxide, titanium white and carbon black can be used as extender pigments or fillers such as talc, clay and mica, and rust preventive pigments such as lead chromate, strontium chromate and basic lead silicate can be used. These pigments can be used in any amount. Furthermore, metal (e.g. lead, tin, bismuth, iron and manganese) salts of organic or inorganic Acids (such as acetic acid, naphthenic acid, hydrochloric acid, and nitric acid) ; Oxides and hydroxides of the metals mentioned are also used as hardening promoters or catalysts will. The addition of surface-active agents to the composition according to the invention is usually not necessary. If desired, however, various known surface active agents (e.g. nonionic wetting agents), which are usually used in electrophoretically depositable, cationic lacquers, are added. Farther conventional leveling agents (e.g. copolymers of alkyl acrylate esters and polyalkylsiloxane) can be added, if it is necessary.

The electrodepositable resin composition of the present invention produced in the above manner can be a

stable, aqueous bath for the electrophoretic deposition of coatings by neutralization with water-soluble ones inorganic or organic acids, such as water-soluble lower, aliphatic monocarboxylic acids, e.g. formic acid, Acetic acid, hydroxyacetic acid, propionic acid, butyric acid and lactic acid; aliphatic dicarboxylic acids, such as Oxalic acid, succinic acid, fumaric acid and maleic acid; aromatic carboxylic acids such as benzoic acid and phthalic acid; organic sulfonic acids such as benzenesulfonic acid and p-toluenesulfonic acid; inorganic acids, such as phosphoric acid, Sulfuric acid and hydrochloric acid, and especially with water-soluble, aliphatic monocarboxylic acids. Primary amino groups, blocked by carbonyl compounds, of the resinous product are released through this neutralization process hydrolyzes and yields strongly basic, primary amino groups. These are primary amino groups for their part neutralized again. The amount of acid required for neutralization should preferably be so determined that at least the necessary amount or more for solubilizing or finely dispersing the resinous Product in the aqueous medium and the necessary amount or less for the complete neutralization of the Amino groups is used in the resinous product. Preferably, the amount of acid should preferably be in the range of about 0.1 to 0.6 equivalent -96 based on the amine value (as defined below) of the resinous product. As for the pH of the aqueous bath thus obtained, the bath should advantageously be neutralized in such a way that the pH of the aqueous bath generally in the range of from about 3 to about 8, preferably from about 5 to about 7.

The concentration of the total solids content in the aqueous bath when the composition according to the invention with an acid neutralized and, when dissolved or dispersed in the aqueous medium, can generally be 3 to

30 wt. 96, preferably 5 to 20 wt. #, Based on the weight of the aqueous bath.

The aqueous bath produced in this way for the electrophoretic deposition of coatings can be used for electrophoretic coating of objects to be coated, which are connected as cathodes.

As to the method and apparatus for electrophoretic coating of a substrate using this aqueous bath, known methods and apparatus can be used in cathodic electrophoretic deposition. For example, it is advisable to use a carbon plate as the anode and the substrate as the cathode. When electrophoretic coating using the composition according to the invention, the conditions are not subject to any particular restrictions, but in general the electrophoretic coating should preferably be at a bath temperature of 20 to 30 ⁰ C, a direct current voltage of 100 to 400 V (preferably 200 to 300 V), a Current density from 0.01 to 3 A / dm, a period for the current circulation of 1 to 5 min, an electrode area ratio (A / 0) of 2/1 to 1/2, a distance between two electrodes of 10 to 100 cm as well as be carried out with stirring.

The deposited on the substrate (cathode) film may, after washing at about 140 to about 250 ⁰ C, preferably hardened about 170 to about 200 ° C, by burning. During the firing process, the blocked isocyanate groups in the film-forming resin release alcohols, the blocking agent, and the crosslinking reaction with the amino groups, amide groups and hydroxyl groups in the resin molecule is carried out. Eventually the resin is hardened.

The electrodepositable resin composition of the present invention can be used to coat or finish various metal products. She is special good for electrophoretic coating not only of common zinc phosphate treated steel substrates, but also from other steel substrates that are sensitive to corrosion, such as those treated with iron phosphate Steel plates and untreated steel plates are suitable. The composition of the invention can have unsurpassed corrosion resistance with excellent scattering power. These advantages could with the conventional, electrophoretically separable paints can not yet be achieved. The mass according to the invention is also for electrophoretic coating of zinc-plated steel plates, tin-plated steel plates, aluminum, copper and copper alloy substrates and forms a coating excellent in scattering power and corrosion resistance.

The invention is illustrated in the examples. "Parts" are always based on weight. The determination and the tests for the tertiary amine value, the amine value, the isocyanate value, the scattering power, the salt spray resistance, the Erichsen extrusion resistance, the impact resistance and the flexibility in the bending test were made by the following methods.

(1) Determination of the tertiary amine value

Approximately 0.2 g of the solids content of the sample was precisely weighed and placed in an Erlenmeyer flask with a conventional stopper. There was about 10 ml of acetic anhydride / acetic acid added in a weight ratio of 9/1. The mixture was Boiled for about 10 minutes in such a way that it did not dry out. Acetylation was effected in this way. After cooling, the product was treated with a 0.1 N per-

Chloric acid-acetic acid solution using crystal violet as an indicator, titrate until it turns purple in color discolored to blue-green.

5.61 χ titrated volume (ml) χ tertiary amine factor of N / 10 HCIO4 value (mg KOH / g) ⁼ solids content of the sample

(2) Determination of the amine value

0.2 to 0.3 g of a sample was placed in a 100 ml Erlenmeyer flask, heated, dissolved and then cooled. The sample was then treated with an aqueous N / 10 HCl solution titrated using bromophenol blue as an indicator. The end point of the titration was found to be the discoloration of Blue after yellow determined. The amine value was calculated by the following equation:

Volume (ml) of N / 10 HCl χ

. . _{VOT1 +} factor of N / 10 HCl _, - ^

Amine value = ^{x 5 '61}

Solid content (90/100

(3) Determination of the isocyanate value

About 0.5 g of an isocyanate group (NCO) sample was accurately weighed and placed in a flask with a ground stopper. The sample was dissolved in 10 ml of dioxane (purity: reagent grade 1). There are exactly 10 ml of a 2/10 N dibutylamine in dioxane was added, and the mixture was heated for 30 min with shaking at 8O ⁰ C. 100 ml of isopropyl alcohol (purity: reagent grade 1) were then added and excess dibutylamine was titrated with 1/10 N hydrochloric acid using bromophenol blue as an indicator until the indicator turned from blue to yellow-green. Independently of this, a blind test was carried out at the same time without entering the sample. The NCO value was calculated using the following equation: NCO value = (AB) χ 0 _T 0042f χ 1000

Therein mean:

A = amount (ml) of N / 10 hydrochloric acid required for neutralization of 2/10 N dibutylamine is necessary in the blind test;

B = amount (ml) of N / 10 hydrochloric acid used in the Titration of the sample is necessary;

0.0042 β amount (mg) of the isocyanate groups that ml corresponds to N / 10 hydrochloric acid;

f = factor of hydrochloric acid;

¥ = amount (g) of the sample.

(4) Test method for scattering force (tube method)

Test device: device as shown schematically in FIGS. 1 to 3.

In the diagrams, the following symbols have the following Meanings:

V ss stainless steel round vessel (diameter 100 mm, thickness t = 1 mm), free of magnetism;

Z = insulator;

D = support rod (fli = 3 mm, height h = 170 mm);

P = stainless steel pipe (0 «16 mm, h = 340 mm, t = 1 mm), free from magnetism;

A = measuring plate for the thickness of the outer film (30 χ χ 0.8 mm) (see Fig. 2);

B s measuring plate for the internal scattering force (15 x 300 χ 0.4 mm) (see Fig. 3);

T ss mercury thermometer (50 ⁰ C scale); K = rotor;

C = cooling water tank (made of plastic); M = magnetic stirrer;

L = liquid level of the paint sample.

Procedures:

(1) The sample of the paint is placed in the round stainless steel vessel V according to FIG. 1 up to a height of L 27 cm brought in from the ground and it is

door (usually 3O ° C) controlled homogeneously stirring (bath temperature 30 ⁰ C);

(2) The outer plate A, the pipe D and the inner plate B are inserted into the support rod D and into the Vessel V introduced;

(3) the anode and cathode are inserted and care is taken that there is no short circuit;

(4) the tension is in 10 see from 0 to the preselected tension at which the film thickness on the outer plate Is 20 to 25 µm, increased; this is the rate of rise the voltage is controlled so that it does not exceed 10 A;

(5) 3 minutes after the circuit has been established, the power is switched off and then the outer plate, the inner plate and the tube washed with water;

(6) the outer plate and the inner plate are fired;

(7) the tube is washed twice with solvent; especially the inner surface of the pipe will thoroughly washed;

(8) The height of the deposited film on the inner plate is measured (see Fig. 4).

(5) Salt spray resistance

The test was carried out in accordance with JIS-Z 2371. When the corrosion creep width on one side of the linear scraping part falls within 2.0mm and the blistering on the other If the film reaches a maximum of 8F (ASTM) in the scratched part, the result is rated as satisfactory .

(6) Erichsen extrusion resistance

Using the Erichsen extrusion tester, the measurement was made on the extruded distance until the Film crack was observed. The test result means e.g.

7 mm or more that »even if the coated plate is too was pushed out to a depth of 7 mm, no cracking was observed.

(7) Impact resistance (duPont Impact Tester System)

A test plate was placed in a temperature- and humidity-conditioned chamber, which was kept at temperatures of 20 + 1 ^° C. and a humidity of 75 + 296, for 24 hours. A support element and an impact rod with a preselected, spherical end were then placed on the duPont Impact Tester and the test plate was placed in between with the coated surface facing up. Then, a weight having a predetermined weight was dropped on the beater rod from a predetermined height. If neither film cracking nor peeling took place, the result was judged to be satisfactory.

(8) bending test

A white topcoat of the alkyd melamine resin type (AMILAC White, a. Product of Kansai Paint Co., Ltd.) to the electrophoretic coated plate to a dry film thickness of 20 to 30 / µm applied by spraying and the plate was baked at about 140 ° C. for 30 minutes to prepare a test piece.

According to JIS-K 5400-1979, 6.16 (bending resistance) the specimen is bent around a cylindrical rod with a diameter of 10 mm. If neither cracking peeling was still observed in the bent portion of the film, then the result was found to be satisfactory viewed.

Example 1

465 parts of bisphenol Α-type epoxy resin with a number average Molecular weight of about 900 and one

Epoxy equivalent of about 465 (Araldite No. 6071;. A product of Nippon CIBA Geigy Co., Ltd., Japan) were dissolved in 200 parts of methyl ethyl ketone and reacted at 80 ⁰ C by the addition of 105 parts of diethanolamine, until the tertiary amine value to 98 had come up (after about 3 hours or more). Thus "Compound A-1" (hydroxyl group equivalent 285) was obtained.

200 parts of dimer acid type polyamide resin having a number average molecular weight of about 1,000 and an amine value of about 300 (Tohmide No. 225X, a product of Fuji Kasei Co., Ltd., Japan) and 50 parts of methyl isobutyl ketone were heated, refluxed and implemented until the drainage stopped. Then nlchtumgesetzte materials were distilled off under reduced pressure to obtain 240 parts of "Compound B-1 were obtained ⁿ (equivalent of the primary amino groups of about 485).

250 parts of 4,4 ^f -diphenylmethane diisocyanate were dissolved in 162 parts of methyl ethyl ketone and reacted at 50 ° C. by adding 112.5 parts of ethylene glycol monoethyl ether until the isocyanate value dropped to 116. Hexamethylene diisocyanate was then added. A mixture of Compound C-1 and Compound D-1 was obtained.

Compound B-1 and 124 parts of methyl ethyl ketone were added of Compound A-1 obtained above was added, and the mixture was heated to 80 ° C. The mixture was then made from Compound C-1 and Compound D-1 slowly dropwise added at the same temperature and it was reacted at the same temperature until the viscosity increase was completed (about 30 minutes or more). Thus, the resinous product of the present invention was obtained.

14 parts of the resinous product were taken out and with 0.6 parts of acetic acid and 26 parts of deionized water

very well mixed. The mixture was then further mixed and dispersed in a ball mill until a particle size of 15 / µm or less with an addition of 15 parts of titanium white, 5 parts of clay, 0.5 part of carbon black and 1 part of bismuth nitrate was obtained. In this way, 62.1 parts of pigment paste became (I) received.

Separately, there were 126 parts of the resinous of the present invention Product taken out and good with 5 parts diethylene monobutyl ether and 2 parts of polypropylene glycol having a number average molecular weight of 4,000 (Sannix PP-4000, a product of Sanyo Kasei Co., Ltd., Japan). Thereupon 0.8 parts of acetic acid and 20 parts of a 1Oxigen aqueous lead acetate solution were added and thoroughly mixed with it. It was made to a solids content of 3096 by adding 166 parts of deionized Water diluted. Thus, a water-dispersed resin varnish or a clear mass was obtained.

This clear mass was mixed well with the pigment paste (I) prepared above and then diluted to a resin solids content of 1550 with deionized water. Was then further stirred by open by moving at 30 ⁰ C over a period of 24, thereby obtaining an electrophoretic deposition bath.

With this electrophoretic deposition bath, a zinc phosphate treated steel plate and an untreated steel plate were electrophoresed to a film thickness of 20 µm. The product was baked 20 min at 180 ⁰ C and then tested for film performance. The following test results were obtained:

(1) Scattering force: 22.0 cm (tube method, 250 V χ 3 min)

(2) Salt spray resistance: untreated steel plate = 360 h

or more

3109782

Steel plate treated with zinc phosphate: 840 h or more

(3) Erichsen extrusion resistance: 7 nm or more

(4) Impact resistance: 50 cm or more on the top;

60 cm or more on the bottom side (1.24 cm, 1 kg)

(5) Bending test (after applying a top coat with

an alkyd melamine white coating): 10 mm 0 satisfactory.

Example 2

575 parts of styrene / allyl alcohol copolymer having a number average Molecular weight of about 1150 and a hydroxyl group equivalent of about 220 (RJ-101, a Product of Monsanto Chemical Co., USA) were in 505 parts Dissolved methyl ethyl ketone (compound A-2).

300 parts of a primary amino terminated polyamide resin having a number average molecular weight of about 1500 and an amine value of about 250 (Versamid 115, a product of Nippon Henkel Co., Ltd., Japan) and 50 parts of methyl isobutyl ketone were heated, refluxed and reacted until dehydration stopped. Thereafter, the unreacted materials were distilled off under reduced pressure, thereby releasing the compound B-2 was obtained.

134 parts of diethylene glycol monoethyl ether were added dropwise at 40 ° C. to 217.5 parts of a 2,4- and 2,6-tolylene diisocyanate mixture (Weight ratio 2.4- / 2.6- = 80/20) and reacted at the same temperature until the isocyanate value had dropped to 205. In this way, a mixture of 43.5 parts of unreacted diisocyanate and Parts of monoblocked diisocyanate (mixture of compound C-2 and compound D-2) were obtained.

The compound B-2 was added to the compound A-2 and mixed therewith. This mixture slowly became a mixture

the compound C-2 and the compound D-2 were added dropwise at 80 ^° C., and the resulting mixture was reacted at the same temperature until the increase in viscosity was terminated. Then 250 parts of methyl ethyl ketone were distilled off by adding 250 parts of ethylene glycol monoethyl ether under reduced pressure, whereby a resinous product according to the invention was obtained.

126 parts of the resinous product was added to 1.0 part of acetic acid, 2.0 parts of lead acetate and 96 parts of deionized water are added and mixed thoroughly, creating a water-dispersed resin varnish having a resin solid content of 4056 was obtained. The one made in Example 1 Pigment paste (I) was added to this varnish and mixed well with it. The resulting mixture was deionized with Water was diluted to a resin solids content of 1856 and the resulting product was subjected to electrodeposition used. The test panels were subjected to the tests of Example 1 for film behavior. There were get the following test results:

(1) Scattering force (pipe method): 23.0 cm (300 V χ 3 min)

(2) Salt spray resistance: untreated steel plate = 240 h

or more

zinc phosphate treated steel plate S = 720 hours or more

(3) Erichsen extrusion: at least 7 mm

(4) Impact resistance: at least 50 cm on the top; min

at least 50 cm on the bottom side (1.27 cm, 500 g)

(5) Flexural test (after applying a top coat with an alkyd-melamine white coating): 10mm0 satisfactory.

Example 3

228 parts of bisphenol A and 200 parts of diglycidyl ether of bisphenol A having an epoxy equivalent of about 200 (Epikote 428, a product of Shell Chemical Co., Ltd., Japan) were heated at 160 ⁰ C and reacted until the epoxy value of zero

- reached 55, whereby Compound A-3 was obtained.

51.5 parts of diethylenetriamine and 120 parts of methyl isobutyl ketone were heated, refluxed, reacted until dehydration was completed, and unreacted materials were distilled off under reduced pressure to obtain 130 parts of Compound B-3. The compound B-3 was slowly added (3 C compound) and 86 parts MethylSthylketon at 40 ⁰ C to a mixture of 84 parts of hexamethylene diisocyanate and reacted at the same temperature, was finished to the heat generation. Thus, a reaction product of the compound B-3 and the compound C-3 was obtained.

A mixed solution of 56.5 parts of £ -caprolactam and 49 parts Methyl ethyl ketone was added dropwise to 74 parts of hexamethylene diisocyanate at 60 ° C, and the mixture was reacted, until the isocyanate value reached about 150. Thus Compound D-3 was obtained.

170 parts of diethylene glycol dimethyl ether were added and dissolved in compound A-3. The reaction product of the compound B-3 and the compound C-3 slowly became dropwise at 60 ° C and then continued to react at the same temperature until the viscosity increase stopped was by further slowly adding Compound D-3. In this way, the resinous of the present invention was obtained Product received.

3.5 parts of 7O # strength hydroxyacetic acid and 106.5 parts of deionized Water was added to 140 parts of the resinous product, thereby forming a water-dispersed resin varnish with a Resin solids content of 4096 was obtained.

3 parts of carbon black, 3 parts of clay and 2 parts of basic lead sulfate were added and the pigment resin varnish was mixed

- 56 -

land with a shaker for paints dispersed until the particle size was 20 µm or less. Then were 0.5 part of a perfluoroalkyl acrylate copolymer (Fluorad FC-430, a product of Sumitomo Three M Co., Ltd., Japan) added. The product was diluted to 1896 resin solids with deionized water and then diluted examined for film properties as in Example 1.

(1) Scattering force (pipe method): 20 cm (220 V χ 3 min)

(2) Salt spray resistance:

Untreated steel plate = treated with zinc phosphate for 360 hours or more

Steel plate = 720 h or more

(3) Erichsen extrusion: at least 6.5 mm

(4) impact resistance; at least 50 cm at the top;

at least 50 cm on the bottom side (1.27 cm, 500 g)

(5) Bending test (after applying a top coat with

an alkyd melamine white coating): 10 mmjf, satisfactory

Example 4

228 parts of bisphenol A (Compound A-4) was dissolved in 120 parts of methyl ethyl ketone and the solution slowly increased at 60 ° C added to 210 parts of hexamethylene diisocyanate (compound C-4). The mixture was reacted at the same temperature until the isocyanate value dropped to 24. Thus, a reaction product of Compounds A-4 and obtained from compound C-4.

26 parts of hydroxyethylethylenediamine and 30 parts of methyl isobutyl ketone were heated, refluxed and reacted until the dehydration ceased. Then were the unreacted materials were distilled off under reduced pressure, whereby 46.5 parts of Compound B-4 were obtained became. 60 parts of methyl ethyl ketone were added to Compound B-4, and the reaction product of Compounds A-4 and the compound C-4 was slowly added at 40 ° C, whereby

a reaction product was obtained from the compound A-4, the compound C-4 and the compound B-4.

130 parts of 2-ethylhexanol were added at 60 ⁰ C to 87 parts of 2,4- and 2,6-Tolylendlisocyanatgemisches (weight ratio: 2,4 / 2,6 β 80/20) and the product obtained was in the same Temperature reacted until the isocyanate value was zero. Thus, diblocked diisocyanate (Compound D-4) was obtained. The compound D-4 was added to the reaction product consisting of the compound A-4, the compound C-4 and the compound B-4, whereby a resinous product of the present invention was obtained.

130 parts of the resinous product were taken out and made into a water-dispersed varnish having a resin solid content of 40J6 by adding 1.5 parts of acetic acid and 118.5 parts of deionized water.

3 parts of carbon black, 6 parts of talc and 3 parts of basic lead silicate were added and the pigmented paint was mixed and dispersed with a paint shaker until the particle size reached 20 µm or less. Then, 0.5 part of perfluoroalkyl acrylate copolymer (Fluorad FC-430, a product of Sumitomo Three M Co., Ltd., Japan) added. The resulting material was diluted with deionized water to a resin solids content of 20%, and then the film test was carried out as in Example 1, whereby the following test results were obtained became:

(1) Scattering force: 18.5 cm (250 V χ 3 min)

(2) Salt spray resistance:

Untreated steel plate: 360 hours or more treated with zinc phosphate. Steel plate: 840 hours or more

(3) Erichsen extrusion: 6.5 mm

(4) Impact resistance: at least 50 cm on the top;

at least 50 cm on the bottom side (1.27 cm, 500 g)

(5) Flexural test (after applying a top coat with an alkyd melamine white coating): 10 mm0, satisfactory.

Example 5

475 parts of bisphenol Α-type epoxy resin with a number average Molecular weight of about 1000 and an epoxy equivalent of about 475 (Epikote 1001, a product of Shell Chemical Co., Ltd., Japan) was dissolved in 53 parts of toluene and the mixture was allowed to stir at 60 ° C for about 3 hours with the addition implemented by 59 parts of n-propylamine. The unreacted amine was then distilled off under reduced pressure, whereby Compound A-5 was obtained.

300 parts of a dimer acid type polyamide resin having a number average Molecular weight of about 1500 and an amine value of about 250 (Versamid 115, a product of Nippon Henel Co., Ltd., Japan), 50 parts of toluene and 50 parts of methyl ethyl ketone were heated, refluxed and dehydrated to obtain Compound B-5.

67.5 parts of ethylene glycol monoethyl ether were added to 130.5 parts of 2,6-tolylene diisocyanate and the mixture was reacted at 40.degree. C. until the isocyanate value had dropped to 159. Thus Compound D-5 was obtained. The compound D-5 was slowly added ^{to the compound B-5 at 60 °} C. and the mixture was reacted at the same temperature for 1 hour. Compound A-5 and 300 parts of propylene glycol monomethyl ether were then added and 42 parts of hexamethylene diisocyanate (Compound C-5) were slowly added at 60.degree. It was reacted at the same temperature for 1 hour, whereby a resinous product of the present invention was obtained.

- 59 -

140 parts of the resinous product were taken out and made into a water-dispersed resin varnish having a solids content of 3396 by adding 20 parts of acetic acid and parts of deionized water. After pigmentation to the resin varnish and preparation of a bath for electrophoretic deposition, as in _: Example 4, the film test was carried out, with the following results being obtained:

(1) Scattering force: 20 cm (250 V χ 3 min)

(2) Salt spray resistance:

Untreated steel plate: 360 h or more treated with zinc phosphate. Steel plate: 840 h or more

(3) Erichsen extrusion: at least 7 mm

(4) Impact resistance: at least 50 cm on the top;

at least 50 cm on the bottom side (1.27 cm, 500 g)

(5) Flexural test (after applying a top coat with an alkyd melamine white coating): 10 mm0, satisfactory.

Example 6

800 parts of styrene-allyl alcohol copolymer having a number average Molecular weight of about 1600 and a hydroxyl group equivalent of about 300 (RJ-100, a product from Monsanto Chemical Company, USA) (Compound A-6) were dissolved in 320 parts of methyl ethyl ketone.

61 parts of monoethanolamine, 14 parts of toluene and 100 parts of methyl isobutyl ketone were heated, refluxed and dehydrated to give 143 parts of Compound B-6. On the other hand, 336 parts of hexamethylene diiso- (compound C-6) were dissolved in 237 parts of methyl ethyl ketone and reacted at 80 ° C. with the addition of 113 parts of ε · -caprolactam until the isocyanate value had dropped to 280. The mixture was then ^{cooled to 60 °} C. and the reaction was continued with the slow addition of compound B-6 until the exothermic reaction had ended. In this way it became a mixture. *

obtained from compound D-6 and the reaction product of compounds B-6 and C-6. The mixture was slowly added to a solution of the compound A-6 at 80 ^° C. and reacted at the same temperature until the increase in viscosity had practically ended. In this way, the resinous product was obtained according to the present invention.

140 parts of the resinous product was taken out and made into a resinous varnish having a resin solids content of 33 # by adding 3 # 4 parts of acetic acid and 157 parts of deionized water. After the resin varnish had been pigmented and an electrophoretic deposition bath had been prepared as in Example 4, the film test was carried out and the following results were obtained:

(1) Scattering force: 18.0 cm (220 V χ 3 min)

(2) Salt spray resistance:

Untreated steel plate: treated with zinc phosphate for 240 h or more. Steel plate: 720 hours more

(3) Erichsen extrusioni 7 mm

(4) Impact resistance: 50 cm on the top; 50 cm

the bottom side (1.27 cm, 500 g)

(5) Flexural test (after applying a topcoat with an alkyd helamine white coating) : 10mm0 satisfactory.

End of description:

Claims (3)

PATENT LAWYERS DR. WALTER KRAUS DIPLOMAL CHEMIST DR.-ING. ANNEKATE WEISERT DIPL.-ING. SPECIALIZATION CHEMICALS IRMGARDSTRASSE 15 D-8OOO MÜNCHEN 71 TELEPHONE 089 / 797077-797078 TELEX O5-212156 kpat d TELEGRAM KRAUSPATENT 2834 WK / My KANSAI PAINT CO., LTD. Amagasaki, Japan Cationically electrodepositable resin composition having blocked isocyanate groups of the cured type. Claims 1. Cationically electrodepositable resin composition with blocked isocyanate groups of the hardened type, characterized in that they have been obtained thereby is that one (I) (A) a compound which has at least two isocyanate-reactive functional groups in one molecule from active hydrogen containing: amino groups and hydroxyl groups, contains, (B) a compound which in a molecule has at least one primary amino group represented by a carbonyl compound is blocked, and at least one isocyanate-reactive functional group selected from active hydrogen containing amino groups and hydroxyl groups, ent holds, and (C) a diisocyanate compound which contains two free isocyanate groups in one molecule, ■ '- 3 Ί 09282 implement with each other, and that one (II) the above reaction mixture with (D) a partially or fully blocked polyisocyanate compound reacted or mixed, which in a molecule at least two isocyanate groups, one of which or more is / are blocked and does not contain more than one free isocyanate group, wherein the resin composition contains as a main component a resinous product in which the compound component (B) with the blocked primary amino group into the compound component (A) through the diisocyanate compound component (C) has been introduced. 2. Composition according to claim 1, characterized in that the active hydrogen-containing amino group has a secondary Is amino group and that the hydroxyl group is attached to the primary carbon atom. 3 · mass according to claim 1, characterized in that the compound (A) contains an average of 2 to 10 isocyanate-reactive functional groups per molecule. 4. Composition according to claim 1, characterized in that the compound (A) isocyanate-reactive, functional groups in the range from 100 to 2000, preferably 200 to 1000, expressed as the number of equivalents of the isocyanate-reactive, functional groups. 5. Composition according to claim 1, characterized in that the compound (A) has a number average molecular weight from about 100 to about 10,000, preferably from about 200 to about 5000. 6. Composition according to claim 1, characterized in that the compound (A) is a compound of the aromatic type (In the case of a polymer, the main chain of the aromatic type compound is mainly composed of aromatic Rings is formed). 7. Composition according to claim 1, characterized in that the compound (A) is a compound from the group (1) Adducts of an epoxy resin and an amine compound with at least two active hydrogen atoms in one molecule, (2) adducts of an epoxy resin and water or a polyhydric alcohol, (3) phenol-terminated prepolymers formed by addition polymerization reaction of a bisphenol compound with a diepoxy compound or a diisocyanate compound, and (4) copolymerized styrene-allyl alcohol prepolymers 8. Composition according to claim 1, characterized in that the compound (A) is a compound from the group of adducts of a bisphenol-type epoxy resin and an alkanolamine, phenol-terminated prepolymers of bisphenol A and a diisocyanate, and copolymerized styrene-allyl alcohol prepolymers. 9. Composition according to claim 1, characterized in that the amino group blocked by a carbonyl compound in the compound (B) a primary amino group of the general formula ^R 3 in which R £ represents a hydrogen atom or a monovalent one Is a hydrocarbon group with 1 to 6 carbon atoms, R, represents a monovalent hydrocarbon group having 1 to 6 carbon atoms, or R ₂ and R, together represent an alkylene group having not more than 12 carbon atoms. 10. Composition according to claim 1, characterized in that at least a part of the primary amino groups present in the (poly) amine compound in the compound (B) are blocked by a carbonyl group, the (poly) amine compound from group (a) polyamine compounds, which simultaneously contain a primary amino group and a secondary amino group, (b) a Hydroxyl group-containing amine compounds that simultaneously have a primary amino group and a hydroxyl group contain, and (c) a hydroxyl group-containing polyamine compounds, which simultaneously have a primary amino group, a secondary amino group and a hydroxyl group is selected. 11. Composition according to claim 10, characterized in that the (poly) amine compound has a primary amino group equivalent of about 2000 or less. 12. Composition according to claim 1, characterized in that the compound (B) is one equivalent of the isocyanate-reactive, ν has functional groups of about 2000 or less. 13. Composition according to claim 10, characterized in that the (poly) amine compound has a number average molecular weight of about 5000 or less. 14. Composition according to claim 10, characterized in that the (poly) amine compound is a compound from the group N-alkylalkylenediamines, polyalkylenepolyamines, N-hydroxyalkylalkylenediamines, Mono- (hydroxyalkyl) amines, N- (aminoalkyl) piperazines, and Is polyamide polyamines. ■ ■■ - 3109? 82 ~ 5 - 15. Composition according to claim 10, characterized in that the (poly) amine compound is a compound of the Group monoethanolamine, monopropanolamine, monobutanolamine, Diethylenetriamine and dimer acid-polyalkylenepolyamine condensate is. 16. Composition according to claim 1, characterized in that the diisocyanate compound (C) has a molecular weight has from about 100 to about 2000. 17. Composition according to claim 1, characterized in that the diisocyanate compound is a compound of the Group 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 1,4-xylylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 1,6-hexamethylene diisocyanate, Isophorone diisocyanate, ethylene glycol, diethylene glycol, 2,4-tolylene diisocyanate adducts of propylene glycol and reaction products of 1 mole of 2,4-tolylene diisocyanate adducts of trimethylol propane with 1 mole of lower aliphatic monoalcohols. 18. Composition according to claim 1, characterized in that the partially or completely blocked polyisocyanate compound obtained by the isocyanate groups contained in the polyisocyanate compound whose molecular weight falls in the range of 100 to 2,000 are partially or completely blocked have been. 19 · Composition according to claim 18, characterized in that the blocking using a volatile, active hydrogen-containing compound having a low molecular weight of not more than JOO has been. 20. Composition according to claim 19 »characterized in that the low molecular weight, active hydrogen containing Compounds are aliphatic monoalcohols. 21. Composition according to claim 1, characterized in that the compound (D) partially blocked polyisocyanate compounds are. 22. Composition according to claim 1, characterized in that the compound (A) in an amount of 30 to 80% by weight, based on the total amount of the compounds (A), (B), (C) and (D) has been used. 23. Composition according to claim 1, characterized in that the compound (B) is used in such proportions has been that the equivalent of the primary amino groups of the resinous product reaches 300-3000. 24. Composition according to claim 1, characterized in that the compound (C) in an amount of almost 1 mol / mol of the compound (B) has been used. 25. Composition according to claim 1, characterized in that the compound (D) is used in such proportions that one equivalent of blocked isocyanate groups of the resinous product has been reached from 400 to 4000. 26. Aqueous bath for the cationic electrophoretic Separation, characterized in that it contains: (I) a cationically electrodepositable resin composition with blocked isocyanate groups from the hardened one Type obtained by. (I) (A) a compound which has at least two isocyanate-reactive functional groups in one molecule, selected from active hydrogen-containing amino groups and hydroxyl groups, contains, (B) a compound that contains in a molecule at least one primary amino group represented by a carbonyl compound is blocked, and at least one isocyanate-reactive, functional group selected from active Hydrogen-containing amino groups and hydroxyl groups, contains, and (C) a diisocyanate compound which contains two free isocyanate groups in one molecule, implement with each other, and that one (II) the above reaction mixture with (D) a partially or fully blocked polyisocyanate compound reacted or mixed which in a molecule at least two isocyanate groups, one or more of which is or are blocked, and not contains more than one free isocyanate group, the resin composition being a resinous one as the main component Contains product in which the compound component (B) having the blocked primary amino group in the compound component (A) has been introduced by the diisocyanate compound component (C); (II) a water-soluble organic or inorganic acid as a neutralizing agent for the resin composition (I); and (III) an aqueous medium. 27. Aqueous bath according to claim 26, characterized in that it contains 3 to 30% by weight of the reaction product as solids (I), based on the weight of the aqueous bath, contains. 28. Aqueous bath according to claim 26, characterized in that it has a pH in the range of about 3 to has about 8. - - ^: * - "■ -"'■■■■ ^: 3Ί 09282 Process for the electrophoretic coating of an electrically conductive surface, which acts as a cathode acts in which an electric current passes through the cathode and an anode is passed in contact with an aqueous, electrophoretically depositable mass, characterized in that that the electrophoretically separable mass contains the following: (I) a cationically electrodepositable resin composition with blocked isocyanate groups from the hardened one Type which has been obtained by taking (I) (A) a compound contained in a molecule at least two isocyanate-reactive functional groups selected from amino groups containing active hydrogen and hydroxyl groups, contains, (B) a compound present in at least one molecule a primary amino group which is blocked by a carbonyl compound, and at least one isocyanate-reactive, functional group selected from active hydrogen-containing amino groups and hydroxyl groups, contains, and (C) a diisocyanate compound which contains two free isocyanate groups in one molecule, implementation together, and that one (II) the above reaction mixture with (D) a partially or fully blocked polyisocyanate compound reacted or mixed which in a molecule at least two isocyanate groups, one or more of which is or are blocked, and not contains more than one free isocyanate group, the resin composition being a resinous one as the main component Contains product in which the compound component (B) with the blocked primary amino group in the compound component (A) has been introduced by the diisocyanate compound component (C); 3 Ί 09282 (II) a water-soluble organic or inorganic Acid as a neutralizing agent for the resin composition (I); (III) an aqueous medium.