DE19804291A1 - Cathodically depositable electrodip coating composition for metallic substrates - Google Patents

Abstract

A cathodically depositable electrodip coating (I) contains one or more polymer resins that are water dilutable by protonation with acid and optionally contains pigment, filler and other conventional additives. (I) contains 0.001-1 wt.% elemental sulfur (w.r.t. total solids). An Independent claim is included for a process for the production of (I) by dispersion of the elemental sulfur in the polymer resin at 20-200 deg C.

Description

The invention relates to cathodic electrodeposition paints containing a or more synthetic resins water - thinnable by protonation with acid and optionally pigments, fillers and other conventional additives. Furthermore The invention relates to methods for producing the cathodically depositable Electrocoating paints and their use.

Cathodic electrocoating has been used successfully for many years Coating of metallic substrates applied. It takes place in particular as Corrosion protection primer used in the automotive industry. The best Corrosion protection is achieved with electro-dipping paints, the lead in the form of more soluble Contain salts or pigments. The steel sheet to be coated is usually subjected to pretreatment. Here, the steel sheet with a Provide phosphate layer and finally with a chromate-containing solution rinsed. Both lead and chromium are toxic substances that are found in Electro dip painting process is an expensive treatment and expensive disposal cause.

DE-C 32 10 540 describes the addition of elemental sulfur and / or one or more organic, N-containing thio compounds too cathodic separable electrodeposition paints. This is said to add metal ions such as Copper and lead can be reduced or avoided without that To deteriorate the corrosion protection effect of the electro-dip coating.

EP-A 0 462 496 describes the incorporation of mercaptans into the cationic Binder made of epoxy resin and blocked isocyanate. The binder can Formulation of lead-free electrocoat compositions with good  Corrosion resistance can be used on steel substrates. On the Chromate rinsing during the pretreatment of the steel substrate can be dispensed with become.

By modifying epoxy resins with elemental sulfur, one Acceleration of gel formation when curing with aliphatic or cycloaliphatic polyamines and polyaminoamides observed (J. MIeziva et al, Paint and varnish, 1988, pages 514-517). Such compositions can be used for fast curing sealants are used (US-A 4,389,501).

The influence of sulfur on the passivation of iron in alkaline solution was by M. Jayalakshmi et al., Corrosion Vol 48 (1992), pages 918-923 examined.

Organic sulfur compounds are often toxic. Your unpleasant smell generally prevents use in electrocoat formulations even in low concentrations.

Electrodeposition paints, to which elemental sulfur has been added, are common also an unpleasant smell, which is probably due to the formation of slight Amounts of organic sulfur compounds is caused. sulfur Dispersions containing are often unstable and settle quickly when standing.

The object of the present invention was to remedy the disadvantages mentioned and in particular to provide electrocoat materials, which themselves without the addition of Lead or other heavy metal coatings with good adhesion and Provide protection against corrosion. Liability should also be on not pretreated or only phosphated, but not treated with chromium-containing solutions Metal substrates are improved.  

Accordingly, cathodic electrodeposition paints containing a or more synthetic resins water - thinnable by protonation with acid and optionally pigments, fillers and other customary additives found, wherein the electrocoat is 0.001 to 1 wt .-%, based on the Total solid, contains elemental sulfur. Furthermore, procedures for Manufacture of electrocoat materials found.

The dip lacquers contain 0.001 to 1% by weight, preferably 0.01 to 0.5% by weight and in particular 0.01 to 0.2% by weight, based on the total solids, elementary Sulfur. From sulfur contents over 0.5 wt .-%, depending on the Electrocoating components (synthetic resin, crosslinking agent, pigments etc.) coating substrate (sheet steel, phosphating, pretreatment) and the selected deposition conditions, opposite effects occur and liability of the coating as well as the corrosion protection may even deteriorate.

In principle, there are none with regard to the electrocoating components Restrictions. Preferably, components are used which are among the Conditions of incorporation of the sulfur are largely inert.

Examples of synthetic resins are protonation with acids water-thinnable, amino group-containing polymerization, polycondensation or polyadducts.

The epoxy resins described below can preferably be used.

The electrocoat materials which can be used according to the invention can be cationic, Contain amine-modified epoxy resins as cathodically depositable synthetic resins. Such synthetic resins are known and are described, for example, in DE-A-35 18  770, DE-A-35 18 732, EP-B-102 501, DE-A-27 01 002, US-A-4,104,147, EP-A- 4090, EP-A-12 463, US-A-4 031 050, US-A-3 922 253, US-A-4 101 486, US-A- 4,038,232 and US-A-4,017,438. In these patent documents too the manufacture of cationic, amine-modified epoxy resins in detail described.

Cationic reaction products are formed from cationic, amine-modified epoxy resins
(α) optionally modified polyepoxides and (β) amines
Understood. These cationic, amine-modified epoxy resins can be prepared by reacting components (α) and (β) and - if necessary - subsequent protonation. However, it is also possible to react an unmodified polyepoxide with an amine and to carry out further modifications on the amine-modified epoxy resin thus obtained.

Polyepoxides are understood to mean compounds which have two or more Contain epoxy groups in the molecule.

Particularly preferred (α) components are compounds which can be prepared by reacting

• (i) a diepoxide compound or a mixture of diepoxide compounds with an epoxy equivalent weight below 2000 with
• (ii) one under the given reaction conditions Epoxy groups reacting monofunctionally, a phenol or Compound containing thiol group or one Mixture of such compounds,

the components (i) and (ii) in a molar ratio of 10: 1 to 1: 1, preferably 4: 1 to 1.5: 1, are used and the reaction of component (i) with component (ii) at 100 to 190 ° C, optionally in the presence of a Catalyst is carried out (see. DE-OS 35 18 770).

Further particularly preferred (α) components are compounds which can be produced by a at 100 to 195 ° C, possibly in the presence of a Catalyst carried out by a monofunctional reacting starter either an alcoholic OH group, a phenolic OH group or one SH group carries, initiated polyaddition of a diepoxide compound and / or one Mixture of diepoxide compounds, if appropriate together with at least one Monoepoxy compound, to an epoxy resin in which diepoxy compound and Starters are installed in a molar ratio of greater than 2: 1 to 10: 1 (cf. DE-OS 35 18 732).

Polyepoxides, which are used to produce the particularly preferred (α) components and can also be used as (o:) components, are made of polyphenols and Epihalohydrins made polyglycidyl ethers of polyphenols. As polyphenols can e.g. B. very particularly preferably bisphenol A and bisphenol F. become. 4,4'-Dihydroxybenzophenone, bis (4- hydroxyphenyl) 1,1-ethane, bis- (4-hydroxyphenyl) -1,1-isobutane, bis- (4-hydroxy tertiary-butylphenyl) -2,2-propane, bis- (2-hydroxynaphthyl) -methane, 1,5- Dihydroxynaphthalene and phenolic novolak resins are suitable.

Other suitable polyepoxides are polyglycidyl ethers of polyvalent ones Alcohols such as B. ethylene glycol, diethylene glycol, triethylene glycol, 1,2- Propylene glycol, 1,4-propylene glycol, 1,5-pentanediol, 1,2,6-hexanetriol, glycerin and bis (4-hydroxycyclohexyl) -2,2-propane. Polyglycidyl esters of Polycarboxylic acids, such as. B. oxalic acid, succinic acid, glutaric acid,  Terephthalic acid, 2,6-naphthalenedicarboxylic acid and dimerized linoleic acid be used. Typical examples are glycidyl adipate and glycidyl phthalate.

Hydantoine epoxides, epoxidized polybutadiene and Suitable polyepoxide compounds, which can be obtained by epoxidation of an olefinic contains aliphatic compound.

Modified polyepoxides are understood to mean polyepoxides in which at least part of the reactive groups with a modifying Connection have been implemented.

Examples of modifying compounds are:

• - Carboxyl group-containing compounds, such as saturated or unsaturated Monocarboxylic acids (e.g. benzoic acid, linseed oil fatty acid, 2-ethylhexanoic acid, Versatic acid), aliphatic, cycloaliphatic and / or aromatic Dicarboxylic acids of different chain lengths (e.g. adipic acid, sebacic acid, Isophthalic acid or dimeric fatty acids), hydroxyalkyl carboxylic acids (e.g. Lactic acid, dimethylolpropionic acid) and carboxyl-containing polyesters or
• - Amino group-containing compounds, such as diethylamine or ethylhexylamine or Diamines with secondary amino groups, e.g. B. N, N'-dialkylalkylenediamines, such as Dimethylethylene diamine, N, N'-dialkyl polyoxyalkylene amines, such as N, N'- Dimethylpolyoxypropylenediamine, cyanoalkylated alkylenediamines, such as bis-N, N'- Cyanoethyl ethylenediamine, cyanoalkylated polyoxyalkylene amines, such as bis-N, N'- Cyanethylpolyoxypropylenediamine, polyaminoamides, such as. B. Versamide, especially reaction products containing terminal amino groups Diamines (e.g. hexamethylene diamine), polycarboxylic acids, in particular Dimer fatty acids and monocarboxylic acids, especially fatty acids or the Reaction product of one mole of diaminohexane with two moles  especially reaction products containing terminal amino groups Diamines (e.g. hexamethylene diamine), polycarboxylic acids, in particular Dimer fatty acids and monocarboxylic acids, especially fatty acids or the Reaction product of one mole of diaminohexane with two moles Monoglycidyl ether or monoglycidyl ester, especially glycidyl ester α branched fatty acids, such as versatic acid, or
• - Hydroxyl group-containing compounds, such as neopentyl glycol, bisethoxylated Neopentyl glycol, hydroxypivalic acid neopentyl glycol ester, dimethylhydantion N, N'-diethanol, 1,6-hexanediol, 2,5-hexanediol, 1,4-bis (hydroxy methyl) cyclohexane, 1,1-isopropylidene-bis- (p-phenoxy) -2-propanol, Trimethylolpropane, pentaerythritol or amino alcohols, such as triethanolamine, Methyldiethanolamine or hydroxyl-containing alkyl ketimines, such as Aminomethylpropanediol-1,3-methylisobutylketimine or tris (hydroximethyl) - aminomethancyclohexanonketimin as well as polyglycol ether, Polyester polyols, polycaprolactone polyols, polycaprolactam polyols different functionality and molecular weights or
• - Saturated or unsaturated fatty acid methyl esters in the presence of Sodium methylate are transesterified with hydroxyl groups of the epoxy resins.

Primary and / or secondary amines can be used as component (β) become.

The amine should preferably be a water-soluble compound. Examples such amines are mono- and dialkylamines, such as methylamine, ethylamine, Propylamine, butylamine, dimethylamine, diethylamine, dipropylamine, Methylbutylamine and the like. Also suitable are alkanolamines, such as. B. Methylethanolamine, diethanolamine and the like. Furthermore, dialkylaminoalkylamines, such as B. dimethylaminoethylamine, diethylaminopropylamine, Diemethylaminopropylamine and the like. Suitable. It can too  Amines containing ketimine groups, such as, for. B. the methyl isobutyl diketimine from Diethylenetriamine can be used. In most cases low molecular weight amines are used, but it is also possible to use higher molecular weight ones Apply monoamines.

The amines can also contain other groups, but these are said to be the Do not interfere with the implementation of the amine with the epoxy group and not to one Lead gelation of the reaction mixture.

Secondary amines are preferably used as the (β) component.

The necessary for water dilutability and electrical separation Charges can be removed by protonation with water-soluble acids (e.g. boric acid, Formic acid, lactic acid, preferably acetic acid) are generated. Another The implementation of cationic groups is possible through the implementation of Epoxy groups of component (α) with amine salts.

The contained in the electrocoat materials which can be used according to the invention As a rule, cathodically depositable resins are either self-crosslinking and / or are made with a crosslinking agent or mixture Crosslinking agents combined.

Self-crosslinkable resins are available by adding them to the resin molecules reactive groups are introduced, which are under baking conditions with each other react. For example, those containing hydroxyl and / or amino groups Resins blocked isocyanate groups are introduced under Unblock baking conditions and form networked ones Paint films react with the hydroxyl or amino groups. Self-connectable Synthetic resins can, for example, by reacting a hydroxyl and / or  synthetic resin containing amino groups with a partially blocked polyisocyanate, which in statistical means contains one free NCO group per molecule.

In principle, the electrocoat materials which can be used according to the invention can all be used for Suitable electrocoating materials suitable crosslinking agents such. B. phenoplasts, polyfunctional Mannich bases, melamine resins, benzoguanamine resins, blocked Contain polyisocyanates and compounds containing activated ester groups. The electrocoat materials of the invention preferably contain blocked Polyisocyanates as crosslinking agents. The use of blocked polyisocyanates in Electrophoretic paints containing cathodically separable synthetic resins is already long known and among other things also in the patent documents cited above described in detail. Suitable blocked polyisocyanates can For example, be prepared by using a polyisocyanate or a mixture of Polyisocyanates with an alcohol or amine to an NCO group-free Product is implemented.

The elemental sulfur can be immersed in the electrocoat in different ways be introduced. For example, it can be crosslinked with the binder or work as a solution in the binder dispersion or can be in the as Resin used synthetic resin or together with the pigments, fillers or additives are ground to a rubbing resin paste.

Synthetic resin dispersions or rubbing resin pastes can also be used with much higher ones Sulfur concentrations with electrocoating components in the corresponding Ratios are mixed so that the above Weight concentrations, based on the total solids of the Paint formulation result.

The elemental sulfur should be as homogeneous as possible in the respective Electrocoating components are incorporated so that there are none  Settling symptoms during storage or flow problems on the coating when baked.

In a preferred process, the sulfur is added to the resin dispersed. Rapidly stirring dispersants or are preferably used static mixers, which are also suitable for higher viscosities and high gravity enable homogeneous distribution of the sulfur in the binder. Doing so the temperature depends on the respective viscosity of the synthetic resin. The Viscosities of the synthetic resin are usually at the incorporation temperature in the range from 100 to 10000 mPa.s, in particular in the range from 500 to 5000 mPa.s. For example, when using conventional synthetic resins on epoxy / amine Base of elemental sulfur at temperatures in the range of 20 to 200 ° C, preferably from 50 to 150 ° C and particularly preferably between 80 and 120 ° C added and between 5 minutes and 5 hours, preferably 15 to 60 Minutes dispersed in the resin.

The synthetic resins can also contain crosslinking agents or can self-crosslinking synthetic resins can be used. However, the Temperature and dispersion time are chosen so that the crosslinking reaction does not occur or is negligible. Also the synthetic resin and possibly no other paint components under the dispersion conditions react with the elemental sulfur to prevent odors avoid volatile sulfur compounds.

The elemental sulfur as described above is therefore preferred in Dispersed synthetic resin and after cooling to about 20 to 120 ° C, preferably 30 up to 80 ° C one or more crosslinking agents are added and about 5 to 50 minutes homogenized. Then an aqueous with acid and water Synthetic resin dispersion produced by the usual methods.  

However, the acid used to prepare the aqueous dispersion can also fully or partially added to the synthetic resin before the sulfur is dispersed become.

The synthetic resin with the dispersed elemental sulfur can also be used Acid, water, pigments and other usual additives are mixed and added a grinding resin paste are ground. The sulfur can also be combined with the pigments or fillers added to the synthetic resin and with acid, Grind water and other common additives to a rubbing resin paste become.

The aqueous electrocoat materials which can be used according to the invention can, in addition to the Components described above also other common paint components such as e.g. B. organic solvents, pigments, fillers, wetting agents, anti-crater additives etc. included.

The solids content of the electrocoating materials of the invention is in the generally 5 to 40, preferably 10 to 40, particularly preferably 10 to 30 Percent by weight.

The non-volatile portion of the electrocoat materials which can be used according to the invention consists of 35 to 70, preferably 35 to 65 wt .-% of a cathodic separable synthetic resin or a mixture of cathodically separable Synthetic resins, 0 to 45, preferably 10 to 35 wt .-% of one Crosslinking agents or a mixture of different crosslinking agents and 5 to 35, preferably 15 to 35% by weight of pigments and / or Fillers.

The electrocoat materials which can be used according to the invention are used for painting electrically conductive substrates in which

• (1) the electrically conductive substrate in an aqueous electrocoat is dipped
• (2) the substrate is switched as a cathode,
• (3) a film is deposited on the substrate by direct current,
• (4) the painted substrate is removed from the electrocoat and
• (5) the deposited paint film is baked.

The method described above is known and has been used on a large scale for years (cf. also the patent documents cited above). The temperature of the electrodeposition bath is generally between 15 and 35 ° C, preferably between 20 and 30 ° C. The applied voltage can vary over a wide range and can e.g. B. lie between 2 and 1000 V. Typically, however, voltages between 50 and 500 V are used. The current density is usually between about 10 and 100 A / m ² . In the course of the deposition, the current density tends to drop. As soon as the lacquer film is deposited on the substrate, the lacquered substrate is removed from the electrocoating lacquer and rinsed off. The deposited paint film is then burned in. The stoving temperatures are usually 130 to 200 ° C., preferably 150 to 180 ° C. and the stoving time is generally between 10 and 60 min., Preferably between 15 and 30 min.

With the method described above, in principle all can be electrical conductive substrates are painted. As examples of electrically conductive Substrates are made of metal such as steel, aluminum, copper and called the like.

The invention is explained in more detail in the following examples. All information about Parts and percentages are by weight unless expressly stated other is determined.  

1. Production of crosslinking agents 1. 1. Crosslinking agent I

In a reactor equipped with a stirrer, reflux condenser, and internal thermometer Inert gas introduction is equipped, 1046 g of isomers and more functional Oligomers based on 4,4'-diphenylmethane diisocyanate with an NCO Equivalent weight of 135 (Lupranat®M2OS, from BASF; NCO functionality approx. 2.7; Content of 2,2'- and 2,4'-diphenylmethane diisocyanate below 5%) below Submitted nitrogen atmosphere. 2 g of dibutyltin dilaurate are added and drops are added 963 g of butyl diglycol at such a rate that the Product temperature remains below 60 ° C. If necessary. must be cooled. After the end of The temperature is added for a further 60 min. kept at 60 ° C and an NCO Equivalent weight of 1120 determined (based on fixed parts). After resolution 87 g in 774 g of methyl isobutyl ketone and addition of 3 g of dibutyltin dilaurate added melted trimethylol propane at such a rate that a product temperature of 100 ° C is not exceeded. After End of addition is left for a further 60 min. after-react. With the following NCO groups are no longer detectable by control. It is cooled to 65 ° C and diluted simultaneously with 96 g sec-butanol and 30 g methyl isobutyl ketone. Of the Solids content is 70.1% (1 h at 130 ° C).

1.2. Crosslinking agent II

In a reactor, as described in the example above, under Nitrogen atmosphere 1464 g trimerized hexamethylene diisocyanate with a NCO equivalent weight of 191 ("Basonat® PLR 8638, from BASF") and 510 g Methyl isobutyl ketone heated to 50 ° C with stirring. During 4 h 936 g of di-n-butylamine were added dropwise. The temperature is reduced by cooling Kept at 55 ° C. The crosslinking agent solution is then cooled and with  Diluted 90 g n-butanol. During the subsequent check, no NCO Detectable groups. The solids content is 79.8% (1 h at 130 ° C measured).

2. Preparation of an aqueous dispersion which is a cathodically depositable Contains synthetic resin and a mixture of crosslinking agents (D1)

In a reactor, 1228 g of epoxy resin based on bisphenol A with one Epoxy equivalent weight (EEW) of 188 along with 279 g bisphenol A, 268 g Dodecylphenol and 89 g xylene heated to 105 ° C under a nitrogen atmosphere. With the help of a water separator, 20 min. through azetrope Reflux distillation in vacuo traces of water. Then heats one at 130 ° C. and 5 g of N, N-dimethylbenzylamine are added. At this temperature the reaction batch is held until the EEW has reached a value of 870. 39 g of butyl glycol, 204 g of sec-butanol and - after cooling below 115 - are then added ° C - 139 g diethanolamine and cools further to 90 ° C. An hour after Amine is added 192 g of Plastilit 3060 (propylene glycol compound from BASF) to and diluted with 144 g sec-butanol and 55 g propylene glycol phenyl ether and cools quickly to 65 ° C at the same time. Then 39 g of N, N- Dimethylaminpropylamin too, maintains the temperature for half an hour and warmed then to 90 ° C. This temperature is held for 1.5 hours. Then on Cooled to 70 ° C. 743 g of crosslinking agent I (point 1.1.) And 650 g of crosslinking agent II (item 1.2.) Added, 10 min. homogenized and transferred to a dispersion vessel. There are added in portions with stirring 107 g of lactic acid (88% in water) in 2203 g of deionized water. Then 20 min. homogenized before adding another 3593 g deionized water is further diluted in small portions.  

The volatile solvents are removed by distillation in vacuo and then replaced in equal quantities by deionized water. The dispersion has the following key figures:
Solids content: 32% (1 hour at 130 ° C)
Base content: 0.66 milliequivalents / g solids
Acidity: 0.25 milliequivalents / g solids
pH: 6.1

3. Production of a gray pigment paste 3.1. Pigment paste (P1)

2781 g bisphenol A diglycidyl ether, 144 g xylene and 581 g bisphenol A are in Presence of 0.2 g triphenylphosphine at 150-160 ° C up to an EEW of 345 implemented. The mixture is then diluted with 2161 g of butyl glycol and reduced to 49 ° C cooled. Then a mixture of 777 g of 9-amino-3,6-dioxanonan-1-ol and 407 g of N, N-dimethylaminopropylamine within 6 min. admitted what the Temperature rises to 110 ° C. The mixture is kept between 110 for an hour and 115 ° C before 645 g of butyl glycol are added and the mixture to 77 ° C is cooled. 149 g of nonylphenol glycidyl ether are then added. The Temperature then rises to 90 ° C and is held there for one hour, before diluting with 1003 g of butyl glycol and cooling. The solids content of the low viscosity resin solution is 60%.

To prepare the pigment paste, first 280 g of water and 250 g of pre-mixed resin solution described above. Now 5 g of carbon black, 90 g Extender HEWP (English China Clay Int., Great Britain), 315 g titanium dioxide (R. 900), 5 g Bentone EW (Rheox, Germany) and 20 g dibutyltin oxide were added. The mixture is 30 min. long under a high-speed dissolver mixer  predispersed. The mixture is then passed through a small laboratory mill (motor Mini Mill, Eiger Engineering Ltd., Great Britain) for 1 to 1.5 h to one Hegmann fineness of less than / equal to 12 dispersed and with additional water a solids content of 58%.

A segregation-stable pigment paste is obtained.

3.2. Production of a pigment paste containing gray sulfur (P2)

The production takes place as above under point 3.1, whereby together with the Pigments and extenders 3.8 g of elemental sulfur are added.

4. Preparation of an aqueous dispersion which is a cathodically separable Synthetic resin, a mixture of cross-linking agents and elementary Contains sulfur 4.1. Dispersion D2

In a reactor, 1228 g of epoxy resin based on bisphenol A with one Epoxy equivalent weight (EEW) of 188 along with 279 g bisphenol A, 268 g Dodecylphenol and 89 g xylene heated to 105 ° C under a nitrogen atmosphere. With the help of a water separator, 20 min. through azetrope Reflux distillation in vacuo traces of water. Then heats one at 130 ° C. and 5 g of N, N-dimethylbenzylamine are added. At this temperature the reaction batch is held until the EEW has reached a value of 870. 39 g of butyl glycol, 204 g of sec-butanol and - after cooling below 115 - are then added ° C - 139 g diethanolamine and cools further to 90 ° C. An hour after Amine is added 192 g of Plastilit 3060 (propylene glycol compound from BASF) to and diluted with 144 g sec-butanol and 55 g propylene glycol phenyl ether and cools quickly to 65 ° C at the same time. Then 39 g of N, N-  Dimethylaminopropylamine too, maintains the temperature for half an hour and warms up then to 90 ° C. This temperature is held for 1.5 hours.

Then 0.48 g of sulfur powder are added and 30 minutes at 80 ° C. dispersed in synthetic resin.

Then it is cooled to 70 ° C. 743 g are added to the reaction mixture Cross-linking agent I (point 1.1.) And 650 g cross-linking agent II (point 1 2) added, 10 min. homogenized and transferred to a dispersion vessel. There there 107 g of lactic acid (88% in water) in 2203 g are added in portions with stirring deionized water. Then 20 min. homogenized before using another 3593 g of deionized water is further diluted in small portions.

The volatile solvents are removed by distillation in vacuo and then replaced in equal quantities by deionized water. The dispersion has the following key figures:
Solids content: 32% (1 pc at 130 ° C)
Particle size: 112 nm

4.2. Dispersion D3 to D6

The dispersions D2 to D6 are produced in accordance with point 4.1., The amount of sulfur powder used for
D3: 2.4 g,
D4: 4.8 g,
D5: 9.6 g,
D6: 72 g
is. The dispersions can be filtered very well.

5. Production and deposition of electrocoat materials according to the invention 5.1. Electrocoating (ET 3-7)

In each case 2600 g of the dispersions according to item 4.2 become 1500 g deionized water and 25 g of a 10% aqueous lactic acid solution diluted. 646 g of pigment paste P1 are added to the resulting mixture according to point 3 added with stirring. The electrocoat thus obtained is made up to 5000 g with deionized water. After 5 days of aging Room temperature is on a cathodically connected steel test panel deposited. The deposition voltage is 300 V, the deposition time is 2 min. and the bath temperature is set to 30 ° C. The secluded Paint film is rinsed with deionized water and 20 min. long at 165 ° C branded. The baked paint films thus obtained were tested. The Test results can be found in Table 1.

5.2. Electrocoating (ET 2)

2600 g of the dispersion D1 according to point 2 with 1500 g of deionized water as well as 25 g of a 10% aqueous lactic acid solution. To that The resulting mixture is 646 g of pigment paste P2 according to point 3.2. under Stir added. The electrocoat thus obtained is deionized Water made up to 5000 g. After 5 days of aging at room temperature deposited on a cathodically connected steel test panel. The is Separation voltage 300 V, the separation time 2 min. and the bath temperature will set to 30 ° C. The deposited paint film is covered with deionized water rinsed and 20 min. baked at 165 ° C for a long time. The so obtained baked paint films were checked. The test results can be found in Table 1 be removed.  

6. Production and deposition of an electrodeposition paint of the prior art Technology electrocoat (ET 1)

2600 g of the dispersions according to point 2 are with 1500 g of deionized water and 25 parts of a 10% aqueous lactic acid solution. To that The resulting mixture is 646 g of the pigment paste according to item 3.1. under Stir added. The electrocoat thus obtained is deionized Water made up to 5000 g. After 5 days of aging at room temperature deposited on a cathodically connected steel test panel. The is Separation voltage 300 V, the separation time 2 min. and the bath temperature will set to 30 ° C. The deposited paint film is covered with deionized water rinsed and 20 min. baked at 165 ° C for a long time. The so obtained baked paint films were checked. The test results can be found in Table 1 be removed.  

Table 1

Claims (7)

1. Electrodeposition lacquers which can be deposited cathodically, comprising one or more by protonation with acid, water-thinnable synthetic resins and optionally Pigments, fillers and other common additives, characterized in that the electrodeposition paint contains 0.001 to 1% by weight, based on the total solid, of elemental sulfur. 2. Process for the production of cathodically depositable electrocoat materials according to Claim 1 characterized in that the elemental sulfur at temperatures in the Range of 20 to 200 ° C is dispersed in the resin. 3. Process for the production of cathodic electrodeposition paints according to Claim 2, characterized in that the elemental sulfur at temperatures in the Is dispersed in the resin from 50 to 150 ° C, or several crosslinking agents at temperatures in the range of 20 to 120 ° C. be added and then an aqueous with acid and water Dispersion is made. 4. Process for the production of cathodic electrodeposition paints according to Claim 2, characterized in that the sulfur-containing synthetic resin with Acid, water, pigments and other usual additives are mixed and is ground to a rubbing resin paste.   5. Process for the production of cathodically depositable electrocoat materials in accordance with Claim 1 characterized in that the sulfur together with the pigments or fillers is added to a synthetic resin and with acid, water and other common additives are ground to a rubbing resin paste. 6. Use of the electrocoat materials according to claim 1 for deposition metallic substrates.