EP0946657A1 - Peinture et additif pour le trempage electrophoretique cathodique - Google Patents

Peinture et additif pour le trempage electrophoretique cathodique

Info

Publication number
EP0946657A1
EP0946657A1 EP97953860A EP97953860A EP0946657A1 EP 0946657 A1 EP0946657 A1 EP 0946657A1 EP 97953860 A EP97953860 A EP 97953860A EP 97953860 A EP97953860 A EP 97953860A EP 0946657 A1 EP0946657 A1 EP 0946657A1
Authority
EP
European Patent Office
Prior art keywords
electrocoat
added
amino groups
compounds
mixture
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP97953860A
Other languages
German (de)
English (en)
Inventor
Klaus Arlt
Walter Jouck
Guido Wilke
Udo Strauss
Wolfgang Bremser
Edwin Cramer
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
BASF Coatings GmbH
Original Assignee
BASF Coatings GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by BASF Coatings GmbH filed Critical BASF Coatings GmbH
Publication of EP0946657A1 publication Critical patent/EP0946657A1/fr
Withdrawn legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
    • C09D5/44—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes for electrophoretic applications
    • C09D5/4488—Cathodic paints
    • C09D5/4492—Cathodic paints containing special additives, e.g. grinding agents
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
    • C09D5/44—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes for electrophoretic applications
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
    • C09D5/44—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes for electrophoretic applications
    • C09D5/448—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes for electrophoretic applications characterised by the additives used

Definitions

  • the invention relates to a method for producing an electrocoat, an electrocoat produced by the process and its use to improve edge protection in electrocoats.
  • Electrocoating in particular cathodic electrocoating, is an increasingly common method for coating electrically conductive objects in recent years, in which preferably water-thinnable, cationic group-bearing synthetic resins are deposited electrophoretically on the surface to be coated become.
  • the KTL finds a preferred application in the priming of device housings and automobile bodies.
  • Electric immersion baths suitable for the purposes mentioned are e.g. described in the following patent documents: US-3,799,854; U.S. 3,984,299; U.S. 4,031,050; U.S. 4,252,703; U.S. 4,332,711; DE-31 08 073; DE-27 01 220; DE-31 03 642; DE-32 15 891; EP-0505 445; EP-0074634; EP-0358221.
  • Resins which can be electrodeposited on the cathode are described, for example, in US Pat. No. 3,617,458. It is a cross-linkable coating compound that is deposited on the cathode. These coating compositions are derived from an unsaturated polymer which contains amine groups and carboxyl groups and an epoxidized material. US Pat. No. 3,663,389 describes compositions which can be deposited electrically and electrically and which are mixtures of certain amine-aldehyde condensates and a large number of cationic resinous materials, one of these materials being reacted with an organic polyepoxide with a secondary amine and solubilizing with Acid can be produced.
  • aqueous dispersions which can be deposited electrically on the cathode and consist of an epoxy resin ester, water and tertiary amino salts.
  • the epoxy ester is the reaction product of glycidyl polyether and a basic unsaturated oleic acid.
  • the amine salt is the reaction product of an aliphatic carboxylic acid and a tertiary amine.
  • Binder based on epoxy and polyurethane for the use of binder dispersions and pigment pastes are also known in numerous configurations. For example, reference is made to DE-27 01 002, EP-A-261 385, EP-A-004090 and DE-PS 3630 667.
  • the KTL offers great advantages over other state-of-the-art processes due to its good material yield and the fact that organic solvents are largely avoided.
  • the lacquer layer During the heating of the lacquer layer, however, it first becomes liquid and reaches its so-called minimum viscosity at a certain temperature. As the temperature continues to rise, the viscosity of the applied coating then increases again due to the crosslinking of the binders. In the thin liquid phase in the area of the viscosity minimum, the effect now occurs that the lacquer layer flows away from the edges of the workpiece due to interfacial forces. This reduces the thickness of the paint layer remaining on the edge, and in the worst case, the edge is even completely exposed.
  • a disadvantage of the described methods is that they are relatively complex and complicated. Furthermore, an increase in the edge protection is accompanied by a deterioration in the course. This is because a uniform, smooth course of the electrocoat layer is not least produced by the fact that the lacquer layer liquefies during the baking and is evenly distributed in the process. The increase described the minimum viscosity of the electrocoat layer therefore generally results in a deterioration in the film flow.
  • the object of the present invention is to achieve a considerable improvement in edge protection with a simple and inexpensive method for producing electrocoat materials from aqueous binder dispersions.
  • aldehydes are not only suitable as such, but also those compounds which are able to split off aldehydes or aldehyde groups.
  • the use of formaldehyde is particularly preferred according to the invention.
  • the aldehyde is added as a 35-45% aldehyde solution.
  • Such solutions are commercially available in the case of the invention according to preferred formaldehyde such as formalin under the name ®.
  • the content of the aldehydes in the solution or compounds which release aldehydes depends on the intended use. In principle, however, the additives can consist of up to 100% aldehyde.
  • R is a hydrogen atom or an alcyl radical having 1-10 C atoms.
  • the compounds containing amino groups which can be used in the context of the invention are preferably reactive with the aldehydes, ie have primary or secondary amino groups. If reactive amino lip-containing compounds are added, an improvement in edge protection is based on the following relationships. A deposited film lowers its viscosity during curing at a higher temperature, before the crosslinking reaction has started or has progressed sufficiently. As a result, the film interferes with the edges during curing due to interfacial forces. With the use of aldehydes and compounds containing amino groups reactive with aldehydes, whether it is a binder containing amino groups or a different additional compound containing amino groups, the time and temperature-dependent development of the viscosity mentioned during curing is advantageously influenced.
  • the amino group-containing compound and the aldehyde react with one another and the reaction product increases the viscosity of a deposited film in the initial phase of the temperature increase in the course of the curing.
  • this increase in viscosity is probably only an intermediate one, since, as the temperature increases, a reduction in viscosity (compared to the viscosity development when using, for example, microgels) occurs with the 5a
  • the mixture can then be added to commercial dip lacquers in an amount that the user can control.
  • the amounts are preferably adjusted so that the aldehyde content in the electrocoat material is between 50 to 1,000 ppm, preferably 200 to 500 ppm.
  • aldehydes or aldehyde mixtures according to the invention described can in principle be added to all commercially available electrocoat materials or binders to improve edge protection.
  • the electrocoat does not contain a catalyst, this can accordingly be added separately to the electrocoat.
  • These are generally metals, in particular heavy metals, metal-containing compounds or mixtures. These can preferably be present as divalent cations in the electrocoat material. According to the invention, the presence of lead has proven to be particularly advantageous. The following can be considered here: Mixtures containing lead or compounds releasing lead cations.
  • the catalysts are added in amounts of about 200 to 800 ppm, particularly preferably 350-650 ppm, based on the electrocoat material.
  • the electrocoat used contains the necessary compounds with amino groups, for example in the form of binders with primary amino groups. However, it is also possible to add the amino group-carrying compounds separately to the electrocoat material. It is also possible to first mix these compounds with the aldehyde - as already described above - and then to add the reaction adduct produced in this mixture to the electrocoating material.
  • Suitable electrocoating materials are both electrocoating materials which can be deposited on the anode, but preferably electrocoating materials which can be deposited on the cathode.
  • anodically depositable electrodeposition paint binders and paints (ATL) containing anionic groups which can be used according to the invention are known and are described, for example, in DE-A-28 24 418. These are, for example, binders based on polyesters, epoxy resin esters, poly (meth) acrylates, maleate oils or polybutadiene oils.
  • the binders carry, for example, -COOH, -SO3H and / or P03H2 groups. After neutralization of at least some of the acidic groups, the resins can be converted into the water phase.
  • the lacquers can also be crosslinkers commonly used, e.g. Contain triazine resins, crosslinkers with groups capable of transesterification and / or transamidation or blocked polyisocyanates.
  • the cathodically depositable electrocoat materials can contain any aqueous cathodically depositable synthetic resin suitable for aqueous electrocoat materials.
  • Binders and crosslinking agents which can be used in KTL lacquers are described in EP-A-82 291, EP-A-234 395, EP-A-209 857, EP-A-227 975, EP-A-178 531, EP-A-333 327, EP-A-310 971, EP-A-456 270, EP-A-261 385, EP-A-245 786, EP-A-414 199, EP -A-476 514, DE-A-33 24 211 and US-A-3,922253.
  • electrocoat materials preferably contain cationic, amine-modified epoxy resins as cathodically depositable synthetic resins.
  • synthetic resins are known and are described, for example, in DE-A-35 18 770, DE-A-35 18 732, EP-B-102501, DE-A-27 01 002, US-A-4,104,147, EP-A-4090 , EP-A-12463, US-A-4,03,050, US-A-3,922,253, US-A-4, 101,486, US-A-4,038,232 and US-A-4,017,438.
  • the preparation of cationic, amine-modified epoxy resins is also described in detail in these patent documents.
  • Cationic reaction products are formed from cationic, amine-modified epoxy resins
  • These cationic, amine-modified epoxy resins can be prepared by reacting components ( ⁇ ), ( ⁇ ) and, if appropriate, ( ⁇ ) 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 contain two or more epoxy groups in the molecule.
  • Particularly preferred ( ⁇ ) components are compounds which can be prepared by reacting
  • components (i) and (ii) being used in a molar ratio of 10: 1 to 1: 1, preferably 4: 1 to 1.5: 1, and the reaction of component (i) with component (ii) 100 to 190 ° C, optionally in the presence of a catalyst, is carried out (cf. DE-A-35 18 770).
  • ⁇ components are compounds which can be prepared by a starter which reacts at 100 to 195 ° C., optionally in the presence of a catalyst, by a monofunctional reactant which either contains an alcoholic OH group or a phenolic OH group.
  • a starter which reacts at 100 to 195 ° C., optionally in the presence of a catalyst, by a monofunctional reactant which either contains an alcoholic OH group or a phenolic OH group.
  • Group or an SH group initiated polyaddition of a diepoxide compound and / or a mixture of diepoxide compounds, optionally together with at least one mono-epoxide compound 10 an epoxy resin in which the diepoxide compound and starter are installed in a molar ratio of greater than 2: 1 to 10: 1 (cf. DE-A-35 18732).
  • Polyepoxides which can be used for the production of the particularly preferred ( ⁇ ) components and also themselves as ( ⁇ ) components are polyglycidyl ethers of polyphenols prepared from polyphenols and epi-halohydrins.
  • polyphenols e.g. bisphenol A and bisphenol F are very particularly preferably used.
  • 4,4'-dihydroxybenzophenone bis (4-hydroxyphenyl) l, l-ethane, bis- (4-hydroxyphenyl) -l, l-isobutane, bis- (4-hydroxy-tertiary-butylphenyl) are also ) -2,2-propane, bis- (2-hydroxynaphthyl) methane, 1,5-di-hydroxynaphthalene and phenolic novolak resins.
  • polyglycidyl ethers of polyhydric alcohols e.g. Ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,4-propylene glycol, 1,5-pentanediol, 1,2,6-hexanetriol, glycerol and bis- (4-hydroxycyclohexyl) -2,2-propane.
  • Polyglycidyl esters of polycarboxylic acids e.g. Oxalic acid, succinic acid, glutaric acid, terephthalic acid, 2,6-nphthalinedicarboxylic acid and dimerized linoleic acid can be used.
  • Typical examples are glycidyl adipate and glycidyl phthalate.
  • Hydantoine epoxides epoxidized polybutadiene and polyepoxide compounds which are obtained by epoxidation of an olefinically unsaturated aliphatic compound are also suitable.
  • Modified polyepoxides are understood to mean polyepoxides in which at least some of the reactive groups have been reacted with a modifying compound. 11
  • modifying compounds are:
  • carboxyl groups 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 various chain lengths e.g. adipic acid, sebacic acid, isophthalic acid or dimeric fatty acids
  • hydroxyalkyl carboxylic acids e.g. lactic acid, dimethylolpropionic acid
  • carboxyl-containing polyesters or
  • N, N'-dialkylalkylenediamines such as dimethylethylenediamine, N, N'-dialkylpolyoxyalkyleneamines, such as N, N'-dimethylpolyoxypropylenediamine
  • cyanoalkylated alkylenediamines such as bis-N, N'-cyanoethylethylenediamine, cyanoalkylated polyoxyal -kylenamines, such as Bis-N, N'-
  • hydroxyl groups such as neopentyl glycol, bisethoxylated neopentyl glycol, hydroxypivalic acid neopentyl glycol ester, di- 12 methylhydantoin-N, N'-diethanol, 1,6-hexanediol, 2,5-hexanediol, 1,4-bis (hydroxymethyl) cyclohexane, 1,1-isopropylidene-bis- (p-phenoxy) -2-propanol, trimethylolpropane, pentaerythritol or amino alcohols, such as triethanolamine, methyldiethanolamine or hydroxyl group-containing alkylketimines, such as aminomethylpropanediol-1, 3-methylisobutylketimine or tris (hydroximethyl) aminomethancyclohexanonketol ether, as well as polyether polyol polyol polyols caprolactone poly
  • Primary and / or secondary amines can be used as component ( ⁇ ).
  • the amine should preferably be a water-soluble compound.
  • examples of such amines are mono- and dialkylamines, such as methylamine, ethylamine, propylamine, butylamine, dimethylamine, diethylamine, dipropylamine, methylbutylamine and the like.
  • Alkanolamines such as e.g. Methylethanolamine, diethanolamine and the like.
  • dialkylaminoalkylamines such as e.g. Dimethylaminoethylamine,
  • the amines can also contain other groups, but these should not interfere with the reaction of the amine with the epoxy group and should not lead to gelation of the reaction mixture.
  • Secondary amines are preferably used as the ( ⁇ ) component.
  • the charges required for water dilutability and electrical separation can be generated by protonation with water-soluble acids (e.g. boric acid, formic acid, lactic acid, preferably acetic acid).
  • water-soluble acids e.g. boric acid, formic acid, lactic acid, preferably acetic acid.
  • Another possibility for introducing cationic groups is to react epoxy groups of component ( ⁇ ) with amine salts.
  • Polyols, polycarboxylic acids, polyamines or polysulfides or mixtures of these classes of substances are used as component ( ⁇ ).
  • the polyols in question include diols, triols and higher polymeric polyols such as polyester polyols and polyether polyols.
  • suitable components ( ⁇ ) reference is made to EP-B2-301 293, in particular on page 4, line 31, to page 6, line 27.
  • the cathodically depositable synthetic resins contained in the electrocoat materials are generally either self-crosslinking and / or are combined with a crosslinking agent or a mixture of crosslinking agents.
  • Self-crosslinkable synthetic resins can be obtained by introducing reactive groups into the synthetic resin molecules, which react with one another under baking conditions.
  • blocked isocyanate groups can be introduced into synthetic resins containing hydroxyl and / or amino groups, which block under firing conditions and react with the hydroxyl or amino groups to form crosslinked coating films.
  • Self-crosslinkable synthetic resins can be obtained, for example, by reacting a synthetic resin containing hydroxyl and / or amino groups with a partially blocked polyisocyanate, which on average contains one free NCO group per molecule.
  • the electrocoat materials can be any crosslinking agent suitable for electrocoat materials, e.g. Phenoplasts, polyfunctional Mannich bases, melamine resins, benzoguanamine resins, blocked polyisocyanates and compounds containing activated ester groups.
  • the electrocoat materials preferably contain blocked polyisocyanates as crosslinking agents.
  • blocked polyisocyanates in electrodeposition paints containing cathodically depositable resins has long been known and is also described in detail in the patent documents cited above, for example in EP-B2-301 293, page 6, line 38, to page 7, line 21.
  • the electrocoat materials of the invention are produced by generally well-known methods.
  • Binder is carried out according to well-known methods (see, for example, DE-C-27 01 002 and others) in organic solvents.
  • the binder solutions thus obtained 15 or dispersions are converted into an aqueous phase in neutralized form.
  • the aqueous electrodeposition paints according to the invention can also contain other customary paint constituents, e.g. Contain pigments, fillers, wetting agents, leveling agents, polymer microparticles, anti-foaming agents, anti-crater additives, catalysts, etc.
  • other customary paint constituents e.g. Contain pigments, fillers, wetting agents, leveling agents, polymer microparticles, anti-foaming agents, anti-crater additives, catalysts, etc.
  • the solids content of the electrocoating materials of the invention is generally 5 to 40, preferably 10 to 40, particularly preferably 20 to 40, percent by weight.
  • the non-volatile fraction of the electrocoat materials of the invention consists of up to, preferably up to,% by weight of an electrophoretically depositable binder or a mixture of electrophoretically depositable binders, 0 to, preferably up to,% by weight of a crosslinking agent or a mixture of different crosslinking agents and up to , preferably up to% by weight of pigments and / or fillers.
  • Pigments are preferably incorporated in the form of a pigment paste in the aqueous binder solution or binder dispersion.
  • the production of pigment pastes is generally known and does not need to be explained in more detail here (see D.H. Parker, Principles of Surface Coating Technology, Intersience Publishers, New York (1965) etc.).
  • epoxy-amine adducts containing quaternary ammonium groups are used to produce the pigment pastes.
  • suitable resins are also described, for example, in EP-A-183 025 and EP-A-469 497.
  • the pigment pastes can contain all pigments and / or fillers suitable for electrocoating, for example Titanium dioxide, zinc oxide, antimony oxide, lead sulfate, lead carbonate, barium carbonate, porcelain, clay, potassium carbonate, aluminum silicate, silicon dioxide, magnesium carbonate and magnesium silicate, cadmium yellow, cadmium red, carbon black, phthalocyanine blue, chrome yellow, toluidyl red and iron oxides as well as anti-corrosion pigments, e.g. Zinc phosphate, lead silicate, or organic corrosion inhibitors.
  • suitable for electrocoating for example Titanium dioxide, zinc oxide, antimony oxide, lead sulfate, lead carbonate, barium carbonate, porcelain, clay, potassium carbonate, aluminum silicate, silicon dioxide, magnesium carbonate and magnesium silicate, cadmium yellow, cadmium red, carbon black, phthalocyanine blue, chrome yellow, toluidyl red and iron oxides as well as anti-corrosion pigments, e.g. Zinc phosphate,
  • the electrocoat materials can also contain conventional additives, such as e.g. the homo- or copolymers of an alkyl vinyl ether described in EP-B2-301 293 (see EP-B2-301 293, page 7, lines 21 to 51), polymer microparticles, anti-cratering agents, wetting agents, leveling agents, anti-foaming agents, catalysts and others. in conventional amounts, preferably in amounts of up to% by weight, based on the total weight of the electrocoat material.
  • conventional additives such as e.g. the homo- or copolymers of an alkyl vinyl ether described in EP-B2-301 293 (see EP-B2-301 293, page 7, lines 21 to 51), polymer microparticles, anti-cratering agents, wetting agents, leveling agents, anti-foaming agents, catalysts and others. in conventional amounts, preferably in amounts of up to% by weight, based on the total weight of the electrocoat material.
  • the electrocoat materials of the invention can be used for painting electrically conductive substrates in which
  • the applied voltage can vary over a wide range and can be, for example, between 2 and 1000 V. Typically, however, voltages between 5o and 500 V are used.
  • the current density is usually between about 10 and 100 A / m ⁇ . In the course of the deposition, the current density tends to drop. As soon as the paint film is deposited on the substrate, the painted substrate is removed from the electrocoating paint 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.
  • all electrically conductive substrates can be coated with the method described above.
  • substrates made of metal such as steel, aluminum, copper and the like are mentioned as examples of electrically conductive substrates.
  • motor vehicle bodies and their parts are coated according to the invention with the electrocoat materials in question.
  • the electrodeposition paints are preferably used for priming in the context of a multi-layer coating. 18th
  • the following example shows the preparation of a cationic resin containing primary amino groups.
  • Bisphenol A, bisphenol A diglycidyl ether and a bisphenol A-ethylene oxide adduct are heated together and form a modified polyepoxy resin.
  • a blocked isocyanate is given as a crosslinker.
  • a reaction with a mixture of secondary amines then takes place.
  • the resin is partially neutralized with lactic acid and dispersed in water.
  • Emulsifier mixture 5 15.2
  • Liquid epoxy resin made by reaction of bisphenol A and epichlorohydrin with an epoxide equivalent weight of 188 (Shell Chemicals)
  • Polyurethane crosslinker made from diphenylmethane diisocyanate, in which 4.3 of 6 moles of isocyanate are first reacted with butyl diglycol and the remaining 1.7 moles with trimethylol propane.
  • the crosslinker is in an 80% solution of methyl isobutyl ketone and
  • the Epikote 828, bisphenol A and Dianol 265 are heated to 130 ° C. in a reactor with nitrogen blanketing. Then 1.6 parts of the benzyldimethylamine (catalyst) are added, the reaction mixture is heated to 150 ° C. and kept between 150 ° and 190 ° C. for about half an hour and then cooled down to 140 ° C. The remaining amount of benzyldimethylamine is then added and the temperature is kept at 140 ° until an epoxy equivalent weight of 1120 is established after about 2.5 h. Immediately afterwards, the polyurethane crosslinker is added and the temperature is reduced to 100.degree.
  • the mixture of secondary amines is then added and the reaction is held at 115 ° for about 1 h, 20 until a viscosity of approx. 6 dPas is reached (50% solution in methoxypropanol, ICI cone-plate viscometer).
  • the resin is dispersed in the water in which the lactic acid and the emulsifier mixture are dissolved.
  • the desired primary amino groups are formed from the ketimine adduct by hydrolysis.
  • the solid is 35% after this step, increases after
  • the dispersion is characterized by a particle size of approx. 150 nm.
  • This example shows the preparation of an aqueous dispersion which contains a cathodically depositable synthetic resin and a crosslinking agent:
  • the mixture is cooled to 80 ° C. and, after a further 10 min, 1327 parts of the reaction mixture are transferred to a dispersion vessel. 45 parts of lactic acid (88% strength in water) in 728 parts of deionized water are added in portions with stirring. The mixture is then homogenized for 20 minutes before further dilution in small portions with a further 1400 parts of deionized water.
  • the dispersion has the following key figures:
  • Solids content 30% (1 hour at 130 ° C.)
  • Base content 0.68 milliequivalents / g solids
  • the edge coverage can be determined with an edge quality measuring device.
  • Example 3 Analogously to Example 3, the same cathodically depositable ET varnish is mixed with 500 ppm of a hemavetal of formaldehyde and urea or butanediol and deposited after the reaction time of one day. The hemiacetal is cleaved in the weakly acidic medium and reactive formaldehyde is released. Similar results are obtained. An edge quality factor of 90-100% is obtained. The corrosion values according to ASTM on the edge are also improved from grade 5 to 1.

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  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Molecular Biology (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Wood Science & Technology (AREA)
  • Organic Chemistry (AREA)
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Abstract

L'invention concerne un procédé permettant de produire des peintures pour trempage électrophorétique, constituées de dispersions de liants aqueuses, selon lequel on ajoute, éventuellement, à ces dispersions de liants, des catalyseurs, ainsi qu'un ou plusieurs aldéhydes de la formule générale R-CH=0, ou bien un ou plusieurs composés qui libèrent de tel adéhydes, R représentant un atome d'hydrogène ou un reste alcyle présentant un à dix atomes de C.
EP97953860A 1996-12-18 1997-12-18 Peinture et additif pour le trempage electrophoretique cathodique Withdrawn EP0946657A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE19652884A DE19652884A1 (de) 1996-12-18 1996-12-18 Elektrotauchlack und Additiv für die kathodische Elektrotauchlackierung
DE19652884 1996-12-18
PCT/EP1997/007132 WO1998027167A1 (fr) 1996-12-18 1997-12-18 Peinture et additif pour le trempage electrophoretique cathodique

Publications (1)

Publication Number Publication Date
EP0946657A1 true EP0946657A1 (fr) 1999-10-06

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Application Number Title Priority Date Filing Date
EP97953860A Withdrawn EP0946657A1 (fr) 1996-12-18 1997-12-18 Peinture et additif pour le trempage electrophoretique cathodique

Country Status (7)

Country Link
EP (1) EP0946657A1 (fr)
JP (1) JP2001506299A (fr)
KR (1) KR20000057639A (fr)
BR (1) BR9714412A (fr)
CA (1) CA2275415A1 (fr)
DE (1) DE19652884A1 (fr)
WO (1) WO1998027167A1 (fr)

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WO2024130128A1 (fr) * 2022-12-16 2024-06-20 Swimc Llc Système de revêtement réticulable et revêtements préparés à partir de celui-ci

Family Cites Families (3)

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Publication number Priority date Publication date Assignee Title
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CA2275415A1 (fr) 1998-06-25
BR9714412A (pt) 2000-04-18
JP2001506299A (ja) 2001-05-15
DE19652884A1 (de) 1998-10-15
KR20000057639A (ko) 2000-09-25
WO1998027167A1 (fr) 1998-06-25

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