CA1335395C - Process for coating electrically conducting substrates, substrates coated by this process and aqueous electrocoating baths - Google Patents
Process for coating electrically conducting substrates, substrates coated by this process and aqueous electrocoating bathsInfo
- Publication number
- CA1335395C CA1335395C CA000588746A CA588746A CA1335395C CA 1335395 C CA1335395 C CA 1335395C CA 000588746 A CA000588746 A CA 000588746A CA 588746 A CA588746 A CA 588746A CA 1335395 C CA1335395 C CA 1335395C
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- Prior art keywords
- electrocoating bath
- polyoxyalkylenepolyamine
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- weight
- electrocoating
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Classifications
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- 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
- C09D163/00—Coating compositions based on epoxy resins; Coating compositions based on derivatives of epoxy resins
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- 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
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G59/00—Polycondensates containing more than one epoxy group per molecule; Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups
- C08G59/14—Polycondensates modified by chemical after-treatment
- C08G59/1433—Polycondensates modified by chemical after-treatment with organic low-molecular-weight compounds
- C08G59/1438—Polycondensates modified by chemical after-treatment with organic low-molecular-weight compounds containing oxygen
- C08G59/1444—Monoalcohols
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G59/00—Polycondensates containing more than one epoxy group per molecule; Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups
- C08G59/14—Polycondensates modified by chemical after-treatment
- C08G59/1433—Polycondensates modified by chemical after-treatment with organic low-molecular-weight compounds
- C08G59/1483—Polycondensates modified by chemical after-treatment with organic low-molecular-weight compounds containing sulfur
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L63/00—Compositions of epoxy resins; Compositions of derivatives of epoxy resins
-
- 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
- C09D5/4419—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes for electrophoretic applications with polymers obtained otherwise than by polymerisation reactions only involving carbon-to-carbon unsaturated bonds
- C09D5/443—Polyepoxides
- C09D5/4457—Polyepoxides containing special additives, e.g. pigments, polymeric particles
Landscapes
- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Organic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Wood Science & Technology (AREA)
- Materials Engineering (AREA)
- Polymers & Plastics (AREA)
- Molecular Biology (AREA)
- Medicinal Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Emergency Medicine (AREA)
- Paints Or Removers (AREA)
- Agricultural Chemicals And Associated Chemicals (AREA)
- Application Of Or Painting With Fluid Materials (AREA)
- Conductive Materials (AREA)
Abstract
The invention relates to a process for a cathodic electro-coating process, wherein the electrocoating bath contains at least 7.5 % by weight of a polyoxyalkylenepolyamine or a mixture consisting of several polyoxyalkylenepoly-amines of different chemical structures, the percentage by weight referring to the total amount of binders con-tained in the electrocoating bath.
Description
t ~5`395 ' - 1 -BASF Lacke + Farben AG, Munster Process for coating electrically conducting substrates, substrates coated by this process and aqueous electro-coating baths The invention relates to a process for coating electrical-ly conducting substrates, in which process (1) the substrate is immersed in an aqueous electro-coating bath which contains a resin capable of being cathodically deposited, (2) the substrate is connected as cathode, 1û (3) a film is deposited on the substrate by the action of direct current, (4) the substrate is removed from the electrocoating bath and (5) the deposited paint film is baked.
The invention also relates to substrates coated by the process according to the invention and to the electro-coating baths employed in the process according to the invention.
-2 l 3~3~5 27293-36 The cathodic electrocoating process described above is a painting process frequently used primarily for priming, in particular for priming of automotive bodies.
Processes of the type described above have been disclosed, for example, in the following patents: DE-OS
The invention also relates to substrates coated by the process according to the invention and to the electro-coating baths employed in the process according to the invention.
-2 l 3~3~5 27293-36 The cathodic electrocoating process described above is a painting process frequently used primarily for priming, in particular for priming of automotive bodies.
Processes of the type described above have been disclosed, for example, in the following patents: DE-OS
3,518,732, DE-OS 3,518,770, DE-OS 3,409,188, EP-A 4,090 and EP-A
12,463.
Using processes of this type, it is possible to achieve coatings of excellent quality. However, surface defects (particularly craters), well known to a person skilled in the art, often occur in the baked paint film.
Many attempts have been made to suppress the occurrence of surface defects by adding additives. It is true that the surface defects may be eliminated in this manner, but, instead, problems due to adhesion failure usually appear in the overcoated paint films (for example filler and top coat). Problems of this sort occur especially in overcoated paint films containing alkyd resins as binders.
It is attempted in the present invention to overcome or reduce the problems outlined above associated with the prior art.
According to the present invention, the electrocoating bath contains at least 7.5 % by weight of a polyoxyalkylenepolyamine or a mixture of two or more polyoxyalkylenepolyamines of different chemical structures, the percentage by weight referring to the total amount of binders contained in the electrocoating bath.
An advantage achieved by the invention is that paint films can be obtained which, compared with paint films of the prior art, exhibit fewer and/or more faintly pronounced surface defects and do not give rise to defects due to adhesion failure in overcoated paint films, especially in overcoated paint films containing alkyd resins as binders.
A further important advantage achieved by the process according to the invention is that, compared with the prior art, the paint films may possess greater film thicknesses and greater flexibility.
U.S. Patent No. 3,975,250 discloses cationic reactive plasticizers, suitable for use in electrocoating baths, which are prepared by the reaction of partly blocked polyisocyanates with polyoxypropylenediamines. However, a person skilled in the art, faced with the problems mentioned above would not be led directly and without difficulty to the information given in the present invention from U.S. Patent No. 3,975,250.
U.S. Patent No. 4,423,166 discloses an electrocoating process of the type mentioned in the introductory portion of this specification. In this patent, the electrocoating bath contains as anticratering agent an adduct of a polyoxyalkylenepolyamine and a polyepoxide. It is true that the paint films obtained by the process disclosed in U.S. Patent No. 4,423,166 exhibit a lower tendency for surface defect formation, but they give rise to defects due to adhesion failure in the overcoated paint films.
Such defects occur especially in overcoated paint films containing alkyd resins as binders.
The advantages achieved by the present invention are all the more surprising, since U.S. Patent No. 4,423,166, in column 18, describes electrocoating baths which contain up to 7.0 % by .
12,463.
Using processes of this type, it is possible to achieve coatings of excellent quality. However, surface defects (particularly craters), well known to a person skilled in the art, often occur in the baked paint film.
Many attempts have been made to suppress the occurrence of surface defects by adding additives. It is true that the surface defects may be eliminated in this manner, but, instead, problems due to adhesion failure usually appear in the overcoated paint films (for example filler and top coat). Problems of this sort occur especially in overcoated paint films containing alkyd resins as binders.
It is attempted in the present invention to overcome or reduce the problems outlined above associated with the prior art.
According to the present invention, the electrocoating bath contains at least 7.5 % by weight of a polyoxyalkylenepolyamine or a mixture of two or more polyoxyalkylenepolyamines of different chemical structures, the percentage by weight referring to the total amount of binders contained in the electrocoating bath.
An advantage achieved by the invention is that paint films can be obtained which, compared with paint films of the prior art, exhibit fewer and/or more faintly pronounced surface defects and do not give rise to defects due to adhesion failure in overcoated paint films, especially in overcoated paint films containing alkyd resins as binders.
A further important advantage achieved by the process according to the invention is that, compared with the prior art, the paint films may possess greater film thicknesses and greater flexibility.
U.S. Patent No. 3,975,250 discloses cationic reactive plasticizers, suitable for use in electrocoating baths, which are prepared by the reaction of partly blocked polyisocyanates with polyoxypropylenediamines. However, a person skilled in the art, faced with the problems mentioned above would not be led directly and without difficulty to the information given in the present invention from U.S. Patent No. 3,975,250.
U.S. Patent No. 4,423,166 discloses an electrocoating process of the type mentioned in the introductory portion of this specification. In this patent, the electrocoating bath contains as anticratering agent an adduct of a polyoxyalkylenepolyamine and a polyepoxide. It is true that the paint films obtained by the process disclosed in U.S. Patent No. 4,423,166 exhibit a lower tendency for surface defect formation, but they give rise to defects due to adhesion failure in the overcoated paint films.
Such defects occur especially in overcoated paint films containing alkyd resins as binders.
The advantages achieved by the present invention are all the more surprising, since U.S. Patent No. 4,423,166, in column 18, describes electrocoating baths which contain up to 7.0 % by .
weight, based on the total amount of binders contained in the electrocoating bath, of a polyoxyalkylenepolyamine, but produce paint films with pronounced surface defects (cf. Table I in U.S.
Patent No. 4,423,166).
Electrocoating baths for cathodic electrocoating are preferably prepared by first preparing an aqueous dispersion which contains a resin capable of being cathodically deposited and, if appropriate, a crosslinking agent and other customary additives such as, for example, antifoams etc.
s - 1 3 3 5 3 ~ 5 A pigment paste is then incorporated in this aqueous dis-persion.
The pigment paste consists of a ground resin and pigments and/or fillers. In addition, the pigment paste may also contain other additives such as, for example, plasticizers, wetting agents, antioxidants etc.
Examples of pigments and fillers which may be contained in the pigment paste, are: titanium dioxide, antimony oxide, zinc oxide, basic lead carbonate, basic lead sul-fate, barium carbonate, porcelain, clay, calcium carbonate,aluminum silicate, silicon dioxide, magnesium carbonate, magnesium silicate, cadmium yellow, cadmium red, carbon black, phthalocyanine blue, chromium yellow, toluidyl red and hydrated iron oxide.
The preparation of pigment pastes is generally known and need not be explained here in greater detail (cf., for example, D.H. Parker, Principles of Surface Coating Technology, Interscience Publishers, New York (1965);
R.L. Yates, Electropainting, Robert Draper Ltd., Teddington/
England (1966); H.F. Payne, Organic Coating Technology, volume 2, Wiley and Sons, New York (1961)).
The pigment paste is added to the aqueous dispersion de-scribed above in such an amount that the finished electro-coating bath possesses the characteristics required for Z5 the deposition. In most cases the weight ratio of pigment - 6 - I 3 3 ~ 3 9 5 - or filler to the total amount of resin capable of being cathodically deposited and contained in the electrocoating bath is O.OS to 0.5.
After the aqueous dispersion and the pigment paste have been combined and the combination adjusted to a suitable solids content, an electrocoating bath ready-for-use is obtained.
The electrocoating baths used according to the invention may in principle contain all the non-self-crosslinking or self-crosslinking resins capable of being cathodically deposited which are suitable for the preparation of electrocoating baths. The electrocoating baths used ac-cording to the invention may also contain mixtures of different resins capable of being cathodically deposited.
However, electrocoating baths containing cationic amine-modified epoxy resins as the resins capable of being cathodically deposited are preferred. Self-crosslinking as well as non-self-crosslinking cationic amine-modified epoxy resins are known. Non-self-crosslinking cationic amine-modified epoxy resins are preferably used.
Cationic amine-modified epoxy resins are understood to be cationic reaction products from (A) optionally modified polyepoxides and (B) amines.
_ 7 _ l 3 3 5 3 9 5 -~~ Polyepoxides are understood to be compounds which contain two or more epoxide groups in the molecule.
Particularly preferred components (A) are compounds which may be prepared by reacting (a) a diepoxide compound or a mixture of diepoxide com-pounds of an epoxide equivalent weight below 2000 with (b) a compound monofunctionally reactive toward epoxide groups under the given reaction conditions and con-taining a phenol or thiol group, or a mixture of such compounds, the components (a) and (b) being used in a molar ratioof 10:1 to 1:1, preferably 4:1 to 1.5:1, and the reaction of the component (a) with the component (b) being carried out at 100 to 190C in the presence or absence of a catalyst (cf. DE-OS 3,518,770)~
Other particularly preferred components (A) are compounds which may be prepared by a polyaddition of a diepoxide compound and/or a mixture of diepoxide compounds, if de-Z0 sired in conjunction with at least one monoepoxide com-pound, to an epoxy resin in which the diepoxide compound and initiator are incorporated in a molar ratio greater than 2:1 to 10:1, the said polyaddition being carried out at 100 to 195C in the presence of absence of a catalyst and initiated by a monofunctionally reactive initiator carrying either an alcoholic OH group or a phenolic OH
1 3~5395 group or an SH group (cf. DE-OS-3,518,73Z)~
The polyepoxides which may be used for the preparation of the particularly preferred components (A) and may even themselves be used as the components (A), are polyglycidyl ethers of polyphenols prepared from polyphenols and epi-halohydrins. The use of bisphenol A and bisphenol F, for example, as the polyphenols is particularly preferred.
In addition, 4,4'-dihydroxybenzophenone, bis(4-hydroxy-phenyl)-1,1-ethane, bis(4-hydroxyphenyl)-1,1-isobutane, bis(4-hydroxy-tert-butylphenyl)-2,2-propane, bis(2-hydroxynaphthyl)methane, 1,5-dihydroxynaphthalene and phenolic novolak resins are also suitable.
Other suitable polyepoxides are polyglycidyl ethers of polyhydric alcohols, such as, for example, 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,Z-propane.
Polyglycidyl esters of polycarboxylic acids, such as, for example, oxalic acid, succinic acid, glutaric acid, tereph-thalic acid, 2,6-naphthalenedicarboxylic acid and dimerized linoleic acid may be also used. Glycidyl adipate and glycidyl phthalate are typical examples.
Other suitable compounds are hydantoin epoxides, epoxidized polybutadiene and polyepoxide compounds which are obtained _ 9 _ l 3 3 5 3 9 5 by epoxidation of an olefinically unsaturated aliphatic compound.
Modified polyepoxides are understood to be polyepoxides in which some of the reactive groups have been reacted with a modifying compound.
Examples of modifying compounds are:
a) compounds containing carboxyl groups such as saturated or unsaturated monocarboxylic acids (for example benzoic acid, linseed fatty acid, 2-ethylhexanoic acid, versatic acid), aliphatic, cycloaliphatic and/or aromatic dicarboxylic acids of various chain lengths (for example adipic acid, sebacic acid, isophthalic acid or dimeric fatty acids), hydroxyalkylcarboxylic acids (for example lactic acid, dimethylolpropionic acid) as ~ell as polyesters containing carboxyl groups, or b) compounds containing amino groups, such as diethyl-amine or ethylhexylamine or diamines with secondary amino groups, for example N,N'-dialkylalkylenediamines such as dimethylethylenediamine, N,N'-dialkylpolyoxy-alkyleneamines such as N,N'-dimethylpolyoxypropylene-diamine, cyanoalkylated alkylenediamines such as bis-N,N'-cyanoethylethylenediamine, cyanoalkylated poly-oxyalkylene amines such as bis-N,N'-cyanoethylpolyoxy-propylenediamine, Polyaminoamides such as, for example, - 10 - l 335395 -versamides, in particular reaction products containing terminal amino groups, obtained from diamines (for example hexamethylenediamine), polycarboxylic acids, particularly dimeric fatty acids, and monocarboxylic acids, in particular fatty acids, or the reaction product of one mole of diaminohexane with two moles of a monoglycidyl ether or monoglycidyl ester, especially glycidyl esters of ~-branched fatty acids such as versatic acid, or c) compounds containing hydroxyl groups such as neopentyl-glycol, bis-ethoxylated neopentylglycol, neopentyl glycol hydroxypivalate, dimethylhydantoin-N,N'-diethanol, hexane-1,6-diol, hexane-2,5-diol, 1,4-bis(hydroxymethyl)-cyclohexane, 1,1-isopropylidene-bis(p-phenoxy)-2-propanol, trimethylolpropane, pentaerythritol or aminoalcohols such as triethanolamine, methyldiethanolamine or alkylketimines containing hydroxyl groups, such as aminomethylpropanediol-1,3-methylisobutylketimine or tris(hydroxymethyl)aminomethanecycl~hexanoneketimine, as well as polyglycol ethers, polyester polyols, poly-ether polyols, polycaprolactone polyols, polycapro-lactam polyols of various functionalities and molecular weights, or d) saturated or unsaturated fatty acid methyl esters which Z5 are transesterified with the hydroxyl groups of the epoxy resins in the presence of sodium methylate.
`~ Primary or secondary amines and their salts, salts of tertiary amines or mixtures of these compounds may be used as the component (B).
~ater-soluble amines are preferably used as the component (B). Examples of suitable amines are monoalkylamines and dialkylamines, such as methylamine, ethylamine, propyl-amine, butylamine, dimethylamine, diethylamine, dipropyl-amine, methylbutylamine etc. Alkanolamines, such as, for example, methylethanolamine and diethanolamine may also be used as components (B). Ketimines of polyamines with primary and secondary amino groups may also be used as the component (B). Furthermore, dialkylaminoalkyl-amines, such as, for example, dimethylaminoethylamine, diethylaminopropylamine and dimethylaminopropylamine, are also suitable as the component (B).
Low-molecular amines are used in most cases as the com-ponents tB). It is also possible, however, to use higher-molecular monoamines.
Secondary amines are preferably used as the components (B).
In many cases several different amines are used as the component (B).
The positive charges required for water dilutability and capacity to be electrically deposited may be imparted by protonation with water-soluble acids (for example boric 1 3353~5 acid, formic acid, lactic acid and, preferably, acetic acid) and/or by the use of amine salts as the components (B) in the binder molecule.
The cationic amine-modified epoxy resins used according to the invention are essentially free from epoxide groups, i.e. their epoxide group content is so low that cross-linking reactions via the epoxide groups cannot take place either before or after the deposition of the paint film.
The cationic amine-modified epoxy resins used according to the invention preferably do not contain any free epoxide groups.
The cationic amine-modified epoxy resins may be used both as non-self-crosslinking resins and as self-crosslinking resins. Self-crosslinking cationic amine-modified epoxy resins may be obtained, for example, by chemical modifica-tion of the cationic amine-modified epoxy resins. A self-crosslinking cationic amine-modified epoxy resin may be obtained, for example, by reacting the cationic amine-modified epoxy resin with a partly blocked polyisocyanate which has on average one free isocyanate group per mole-cule and whose blocked isocyanate groups lose their block-ing groups only at elevated temperatures.
Preferred electrocoating baths are obtained when non-self-crosslinking cationic amine-modified epoxy resins are used as resins capable of being cathodically deposited in com-bination with a suitable crosslinking agent.
Examples of suitable crossLinking agents are phenoplasts, polyfunctional Mannich bases, melamine resins, benzo-guanamine resins, blocked polyisocyanates and compounds containing at least two groups of the general formula R1-o-cO-The radical R1 denotes:
Rl = R20-C0-CH2-, R3-CHoH-CH2-, R4-CHoRS-CHoH-CH2-R = alkyl R3 = H, alkyl, R6-O-CH2- or R6-CO-0-CH2-R4 = H or alkyl RS = H, alkyl or aryl R6 = alkyl, cycloalkyl or aryl Preferred electrocoating baths are obtained when blockedpolyisocyanates and/or compounds containing at least two groups of the general formula R1-û-C0- are used as crosslinking agents.
Any polyisocyanates in which the isocyanate groups have been reacted with a compound in such a way that the blocked polyisocyanate formed is non-reactive toward hydroxyl and amino groups at room temperature, but becomes reactive at elevated temperatures, usually in the range from about 90C to about 300C, may be used as the blocked poly-isocyanates. Any organic polyisocyanates suitable for the crosslinking may be used for the preparation of the blocked polyisocyanates. Isocyanates containing about 1 33~3~S
3 to 36, in particular about 8 to about 15 carbon atoms, are preferred. Examples of suitable diisocyanates are hexamethylenediisocyanate, 2,4-toluylenediisocyanate, 2,6-toluylenediisocyanate and 1-isocyanatomethyl-5-iso-cyanato-1,3,3-trimethylcyclohexane. Ho~ever, it is also possible to employ polyisocyanates of higher isocyanate functionality. Corresponding examples are trimerized hexamethylenediisocyanate and trimerized isophoronediiso-cyanate. In addition, mixtures of polyisocyanates may also be used. The organic polyisocyanates which are suit-able as crosslinking agents for the invention may also be prepolymers derived, for example, from a polyol including a polyether polyol or a polyester polyol.
Any suitable aliphatic, cycloaliphatic or aromatic alkyl-monoalcohols may be used for the blocking of the polyiso-cyanates. Examples of these are aliphatic alcohols, such as methyl, ethyl, chloroethyl, propyl, butyl, amyl, hexyl, heptyl, octyl, nonyl, 3,3,5-trimethylhexyl, decyl and . lauryl alcohol; cycloaliphatic alcohols such as cyclo-pentanol and cyclohexanol; aromatic alkylalcohols suchas phenylcarbinol and methylphenylcarbinol.
Other suitable blocking agents are hydroxylamines such as ethanolamine, oximes such as methyl ethyl ketonoxime, acetone oxime and cyclohexanone oxime or amines such as dibutylamine and diisopropylamine. The above polyiso-cyanates and blocking agents may also be used, in suitable proportions, for the preparation of the partly blocked polyisocyanates referred to above.
Examples of compounds which contain at least two groups of the general formula R1-0-C0-, are bis(carbalkoxy-methyl) azelate, bis(carbalkoxymethyl) sebacate, bis-(carbalkoxymethyl) adipate, bis(carbalkoxymethyl) decanate,bis(carbalkoxymethyl) terephthalate, bis(2-hydroxybutyl) acelate (sic) and bis(2-hydroxyethyl) terephthalate.
The crosslinking agent is usually used in an amount from 5 to 60 % by weight, preferably 20 to 40 % by weight, based on the total amount of crosslinkable resin capable of being cathodically deposited contained in the electro-coating bath.
It is an essential part of the invention that in the process according to the invention electrocoating baths are employed which contain at least 7.5 % by weight of a polyoxyalkylenepolyamine or a mixture of several poly-oxyalkylenepolyamines of different chemical structures, the percentage by weight referring to the total amount of binders contained in the electrocoating bath.
The polyoxyalkylenepolyamines are understood to be com-pounds which contain both oxyalkylene groups as well as at least two amino groups, preferably at least two primary amino groups. The polyoxyalkylenepolyamines should have a number average molecular weight of about 137 to 3600, preferably 400 to 3000, particularly preferably 800 to 2500. Furthermore, the polyoxyalkylenepolyamines should have an amine equivalent weight of about 69 to about 1800, preferably 200 to 1500, particularly preferably 400 to 1Z50.
The polyoxyalkylenepolyamines preferably used have a chemical structure according to the general formula (I) H2N-CHR-CH2-O-(-CHR-CH2-0-)n-CH2-CHR-NH2 (I) in which R denotes H or an alkyl radical of 1 to 6 carbon atoms, preferably -CH3 n denotes S - 60, preferably 20 - 40.
Polyoxyalkylenepolyamines which have a chemical structure in accordance with the general formula (I), are disclosed in US-PS 3,236,895, column 2, lines 40-72. The processes for the preparation of these polyoxyalkylenepolyamines are disclosed in the patent examples 4, 5, 6 and 8 to 12 found in columns 4 to 9 of US-PS 3,236,895.
It is also possible to employ polyoxyalkylenepolyamines which contain different oxyalkylene groups, for example polyoxyalkylene polyamines which have a chemical structure in accordance with the general formula (II):
H2~-cH(cH3)-cH2-(o-cH(cH3)-cH2)n-(o~cH2-cH2-)m{}~H2-cH(c 3) 2 (II) in which n + m denotes S to 60, preferably 20 to 40 m denotes 1 to 59, preferably S to 30 n denotes 1 to 59, preferably 5 to 30.
It is also possible to use polyoxyalkylenepolyamine deriv-atives which are obtainable by the reaction of the poly-oxyalkylenepolyamines described in US-PS 3,236,895, column 2, lines 40-72, with acrylonitrile, followed by hydrogenation of the reaction product.
These derivatives have a chemical structure in accordance with the general structural formula (III):
~2N-(CH2)3-NH-CHR-CH2-0-(-CHR-CH2-0-)n-CH2-CHR-NH-(CH2)3-NH2 (III) in which 5 R denotes H or an alkyl radical of 1 to 6 carbon atoms, preferably -CH3 n denotes 5 to 60, prefereably 20 to 40.
It goes without saying that the electrocoating baths used according to the invention may also contain a mixture of - 18 - l 335395 - several polyoxyalkylenepolyamines of different chemical structures.
The polyoxyalkylenepolyamines or the polyoxyalkylene-polyamine mixtures may be incorporated in the electro-coating baths at any time during the preparation and evento the finished electrocoating baths. The polyoxyalkylene-polyamines or the polyoxyalkylenepolyamine mixtures are preferably added either to the aqueous dispersion or a pre-cursor of the aqueous dispersion which contains a resin 1û capabLe of being cathodically deposited and, optionally, a crosslinking agent and other customary additives such as, for example, antifoams etc. ~cf. page 4, lines 19 ff), or to the pigment paste or a precursor of the pigment paste (cf. page 4, lines Z6 ff).
The polyoxyalkylenepolyamine molecules are in all proba-bility protonized by the acid contained in the aqueous dispersion or the pigment paste.
However, it is also possible to add the corresponding polyoxyalkylenepolyamine or polyoxyalkylenepolyamine mixture in the protonized form to the aqueous dispersion under discussion or a precursor of this dispersion, or to the pigment paste or a precursor of the pigment paste.
The protonized polyoxyalkylenepolyamine or polyoxyalkylene-polyamine mixture may be obtained by the simple addition of a ~ronsted acid to the corresponding polyoxyalkylene-polyamine or polyoxyalkylenepolyamine mixture. The total ~ amount of ~ronsted acid contained in the finished electro-coating bath should be selected in such a manner that the pH of the electrocoating bath is between 4 and 8, pre-ferably between 5 and 7.5.
It is an essential part of the invention that the amount of polyoxyalkylenepolyamine or polyoxyalkylenepolyamine mixture contained in the electrocoating baths used accord-ing to the invention is at least 7.5 % by weight, the percentage by weight referring to the total amount of binders contained in the electrocoating bath. This means in other words that the electrocoating baths used accord-ing to the invention must contain at least 7.5 parts by weight of polyoxyalkylenepolyamine or polyoxyalkylene-polyamine mixture per 100 parts by weight of binder.
When electrocoating baths with a lower content of poly-oxyalkylenepolyamine or polyoxyalkylenepolyamine mixture are used, the resultant paint films exhibit considerably more and/or considerably more strongly pronounced sur-face defects than when the electrocoating baths accord-ing to the invention are used.
The upper limit of the amount of polyoxyalkylenepolyamineor polyoxyalkylenepolyamine mixture contained in the electrocoating baths used according to the invention is determined by the plasticizing effect of the added poly-oxyalkylenepolyamine or polyoxyalkylenepolyamine mixtureand is generally from 20 to 40 % by weight, the percent-age by weight referring to the total amount of binders contained in the electrocoating bath.
The electrocoating baths used according to the invention preferably contain 8 to 18, particularly preferably 10 to 15 % by weight of polyoxyalkylenepolyamine or poly-oxyalkylenepolyamine mixture, the percentage by weightreferring to the total amount of binders contained in the electrocoating bath.
The total amount of binders contained in the electrocoating bath is determined by adding the amount of resin capable of being cathodically deposited contained in the electro-coating bath, the amount of crosslinking agents option-ally contained in the electrocoating bath, the amount of ground resin contained in the electrocoating bath and the amount of resins which crosslink under the baking conditions which may or may not be additionally present in the electro-coating bath.
The solids content of the elec~rocoating baths used ac-cording to the invention is preferably 7 to 35 parts by weight, particularly preferably 12 to Z5 parts by weight.
The electrocoating bath is brought into contact with an electrically conducting anode and with the electrically conducting substrate connected as cathode. When electric current passes between the anode and the cathode, a highly adherant paint film is deposited on the cathode.
- 21 - f 335395 - The temperature of the electrocoating bath should be between 15 and 35C, preferably between 20 and 30C.
The applied voltage may fluctuate within a wide range and may be, for example, between two and one thousand S volt. However, typical operational voltages are between 50 and 500 volt. The current density is usually between about 10 and 100 ampere/mZ. The current density tends to drop in the course of the deposition.
When the deposition is completed, the coated object is rinsed and is then ready for baking.
The deposited paint films are generally baked at tempera-tures from 130 to 200C during a period of 10 to 60 minutes, preferably at 150 to 180C during a period from 15 to 30 minutes.
The process according to the invention may be employed for coating of any electrically conducting substrate, in particular, however, for coating of metals such as steel, aluminum, copper and the like.
The invention is explained in greater detail in the ex-amples below. All parts and percentages are parts and percentages by weight, unless expressly stated otherwise.
- 22 - l 3 3 5 3 9 5 - 1. Preparation of aqueous dispersions containing a resin capable of being cathodically deposited and a cross-linking agent.
1.1 Preparation of an amine-modified epoxy resin 1780 9 of Epikote 10011), 280 9 of dodecylphenol and 105 9 of xylene are placed in a reaction vessel and molten at 120C in an atmosphere of nitrogen.
Traces of water are subsequently removed in a slight vacuum. 3 9 of N,N-dimethylbenzylamine are then added, the reaction mixture is heated to 130C and kept at this temperature for about 3 h until the epoxide equivalent weight (EEW) has risen to 1162. The mixture is then cooled and 131 9 of hexylglycol, 131 9 of diethanolamine and 241 9 of xylene are then added in rapid succession. This causes a slight temperature rise. The reaction mix-ture is then cooled to 90C and further diluted by the addition of 183 9 of butylglycol and 293 9 of iso-butanol. When the temperature has dropped to 70C, 41 9 of N,N-dimethylaminopropylamine are added, the temperature is kept for 3 h and the mixture is then discharged.
The resin has a solids content of 70.2 ~ and a base content of 0.97 milliequivalents/gram.
1) An epoxy resin from Shell with an epoxide equivalent weight of 500.
i~ Tracie - ma~k 1.2 Preparation of a crosslinking agent 1.1Z9 9 of toluylene diisocyanate (commercial mixture of isomers consisting of the 2,4 and 2,6 isomers) and 490 9 of methyl isobutyl ketone are placed in a re-action vessel in an atmosphere of nitrogen. 0.6 9 of dibutyltin dilaurate and then, in small portions, Z90 g of trimethylolpropane are added with stirring in such a manner that with external cooling the internal temperature does not exceed 50C (duration about 2 h).
The reaction mixture is further stirred, while cool-ing, until the NCO equivalent weight has reached a value of 215. 675 9 of ethylene glycol monopropyl ether are then added dropwise at such a rate that the internal temperature does not exceed 100C. The temperature is then kept at 100C for 1 h, the mixture is diluted with 362 g of methyl isobutyl ketone and 10 g of n-butanol, and after brief cooling the mixture is discharged. The resin has a solids content of 71.8 %
(1 h at 130C) and a viscosity of 1.5 dPas (50 %
solution in methyl isobutyl ketone, measured in a plate-cone viscometer).
1.3 Preparation of the aqueous dispersions 1.3.1 Dispersion (I) 915 9 of resin according to procedure 1.1, 493 9 of crosslinking agent according to procedure 1.2 and 134 9 of a polyoxypropylenediamine of the formula 2 3 ) CH2 - ( -aCH2-CH ( CH3 ) ) -NH
x = 33.1 (JeffamineR D 2000, commercial product from Texaco Chemical Company) are mixed at room tempera-ture and stirred. As soon as the solution has become homogeneous, 2.2 g of an antifoam solution1) and 22 9 of glacial acetic acid are stirred in, and 674 9 of deionized water are added in 6 portions.
The mixture is then diluted with further 960 9 of deionized water added in small portions.
The resultant aqueous dispersion is freed from low-boiling solvents by vacuum distillation and subse-quently diluted with deionized water to a solids content of 33 %.
1.3.2 Dispersion (II) The procedure 1.3.1 is followed, except that 67 9 of polyoxypropylenediamine are used in place of 134 9 of polyoxypropylenediamine.
1) Surfynol (commercial product from Air Chemicals), .~ ~
a 50 % strength solution in ethylene glycol monobutyl ether T~G~- ma~ k - 1.3.3 Dispersion (III) Procedure 1.3.1 is followed, except that no poly-oxypropylenediamine is used. After vacuum distil-lation a correspondingly smaller amount of deionized water is added in order to adjust the solids content of 33 %.
2. Preparation of a pigment paste 2.1 Preparation of a ground resin according to DE-OS 3,422,457 640 parts of a diglycidyl ether based on bisphenol A
and epichlorohydrin with an epoxide equivalent weight of 485 and 160 parts of such diglycidyl ether with an epoxide equivalent weight of 189 are mixed at 100C.
452 parts of hexamethylenediamine are placed in a further vessel, heated to 100C and treated with 720 parts of the above hot epoxy resin mixture in the course of ~ne hour, gentle cooling being necessary in order to keep the temperature at 100C. After a further period of 30 minutes the excess hexamethyl-enediamine is removed while increasing the temperature and reducing the pressure, a final temperature of 205C
and a final pressure of 30 mbar being reached. 57.6 parts of stearic acid, 172.7 parts of dimeric fatty acid and 115 parts of xylene are then added. The water formed is then removed by azeotropic distillation at 175 to 180C
in the course of 90 min. 58 parts of butylglycol and - 26 - l 3 3 5 3 9 5 ~~ 3Z2 parts of isobutanol are then added. The product has a solids content of 70 % and a viscosity of 2240 mPas, measured at 75C in a plate-cone viscometer.
2.2 Preparation of the pigment paste 586 parts of the ground resin are thoroughly mixed with 1162 parts of deionized water and 22 parts of glacial acetic acid. The mixture is subsequently treated with 880 parts of TiO2, 250 parts of an ex-tender based on aluminum silicate, 53 parts of lead silicate and 10 parts of carbon black. This mixture is comminuted in a grinding unit to a Hegman fine-ness of less than 12 ~m. Deionized water is then added in order to reach the required paste consistency.
3. Preparation of electrocoating baths and deposited coatings according to the invention 700 parts of the pigment paste according to procedure 2.2 are added to 2200 parts by weight of the dispersions according to procedure 1.3, and the solids content of the bath is adjusted to 20 % by weight using de-ionized water. The deposition of the paint films is carried out for 2 minutes at 300 V on phosphated metal sheet. The bath temperature is 27C. The films are baked at 165C for 20 minutes.
- 27 - l 3 3 5 3 9 5 Electrocoating bath 1: Dispersion according to procedure 1.3.1 with paste according to procedure 2.2 Polyoxypropylenediamine content (based on the total amount of binders): 11.9 % by weight Electrocoating bath 2: Dispersion according to procedure 1.3.2 with paste according to procedure 2.2 Polyoxypropylenediamine content (based on the total amount of binders): 6.0 % by weight Electrocoating bath 3: Dispersion according to procedure 1.3.3 with paste according to procedure 2.2 Polyoxypropylenediamine content:
0 % by weight Deposition results Electrocoating bath 1 2 3 Film thickness (~m) 27 20 16 Flow-out1) 1.5 2.5 1.5 Craters/dm2 1 20 10 - za - 1 3 3 5 3 9 5 These films were then overcoated by a commercial aqueous filler and a white alkyd topcoat, and tested in a con-densed water static test for 240 h. The adhesion of the films was subsequently tested by the crosshatch test and S the Tesa puLl-off test.
Electrocoating bath 1 2 3 Adhesion1) 0.5 0.5 0,5 1)/ Rating 0 - 5 (good - poor)
Patent No. 4,423,166).
Electrocoating baths for cathodic electrocoating are preferably prepared by first preparing an aqueous dispersion which contains a resin capable of being cathodically deposited and, if appropriate, a crosslinking agent and other customary additives such as, for example, antifoams etc.
s - 1 3 3 5 3 ~ 5 A pigment paste is then incorporated in this aqueous dis-persion.
The pigment paste consists of a ground resin and pigments and/or fillers. In addition, the pigment paste may also contain other additives such as, for example, plasticizers, wetting agents, antioxidants etc.
Examples of pigments and fillers which may be contained in the pigment paste, are: titanium dioxide, antimony oxide, zinc oxide, basic lead carbonate, basic lead sul-fate, barium carbonate, porcelain, clay, calcium carbonate,aluminum silicate, silicon dioxide, magnesium carbonate, magnesium silicate, cadmium yellow, cadmium red, carbon black, phthalocyanine blue, chromium yellow, toluidyl red and hydrated iron oxide.
The preparation of pigment pastes is generally known and need not be explained here in greater detail (cf., for example, D.H. Parker, Principles of Surface Coating Technology, Interscience Publishers, New York (1965);
R.L. Yates, Electropainting, Robert Draper Ltd., Teddington/
England (1966); H.F. Payne, Organic Coating Technology, volume 2, Wiley and Sons, New York (1961)).
The pigment paste is added to the aqueous dispersion de-scribed above in such an amount that the finished electro-coating bath possesses the characteristics required for Z5 the deposition. In most cases the weight ratio of pigment - 6 - I 3 3 ~ 3 9 5 - or filler to the total amount of resin capable of being cathodically deposited and contained in the electrocoating bath is O.OS to 0.5.
After the aqueous dispersion and the pigment paste have been combined and the combination adjusted to a suitable solids content, an electrocoating bath ready-for-use is obtained.
The electrocoating baths used according to the invention may in principle contain all the non-self-crosslinking or self-crosslinking resins capable of being cathodically deposited which are suitable for the preparation of electrocoating baths. The electrocoating baths used ac-cording to the invention may also contain mixtures of different resins capable of being cathodically deposited.
However, electrocoating baths containing cationic amine-modified epoxy resins as the resins capable of being cathodically deposited are preferred. Self-crosslinking as well as non-self-crosslinking cationic amine-modified epoxy resins are known. Non-self-crosslinking cationic amine-modified epoxy resins are preferably used.
Cationic amine-modified epoxy resins are understood to be cationic reaction products from (A) optionally modified polyepoxides and (B) amines.
_ 7 _ l 3 3 5 3 9 5 -~~ Polyepoxides are understood to be compounds which contain two or more epoxide groups in the molecule.
Particularly preferred components (A) are compounds which may be prepared by reacting (a) a diepoxide compound or a mixture of diepoxide com-pounds of an epoxide equivalent weight below 2000 with (b) a compound monofunctionally reactive toward epoxide groups under the given reaction conditions and con-taining a phenol or thiol group, or a mixture of such compounds, the components (a) and (b) being used in a molar ratioof 10:1 to 1:1, preferably 4:1 to 1.5:1, and the reaction of the component (a) with the component (b) being carried out at 100 to 190C in the presence or absence of a catalyst (cf. DE-OS 3,518,770)~
Other particularly preferred components (A) are compounds which may be prepared by a polyaddition of a diepoxide compound and/or a mixture of diepoxide compounds, if de-Z0 sired in conjunction with at least one monoepoxide com-pound, to an epoxy resin in which the diepoxide compound and initiator are incorporated in a molar ratio greater than 2:1 to 10:1, the said polyaddition being carried out at 100 to 195C in the presence of absence of a catalyst and initiated by a monofunctionally reactive initiator carrying either an alcoholic OH group or a phenolic OH
1 3~5395 group or an SH group (cf. DE-OS-3,518,73Z)~
The polyepoxides which may be used for the preparation of the particularly preferred components (A) and may even themselves be used as the components (A), are polyglycidyl ethers of polyphenols prepared from polyphenols and epi-halohydrins. The use of bisphenol A and bisphenol F, for example, as the polyphenols is particularly preferred.
In addition, 4,4'-dihydroxybenzophenone, bis(4-hydroxy-phenyl)-1,1-ethane, bis(4-hydroxyphenyl)-1,1-isobutane, bis(4-hydroxy-tert-butylphenyl)-2,2-propane, bis(2-hydroxynaphthyl)methane, 1,5-dihydroxynaphthalene and phenolic novolak resins are also suitable.
Other suitable polyepoxides are polyglycidyl ethers of polyhydric alcohols, such as, for example, 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,Z-propane.
Polyglycidyl esters of polycarboxylic acids, such as, for example, oxalic acid, succinic acid, glutaric acid, tereph-thalic acid, 2,6-naphthalenedicarboxylic acid and dimerized linoleic acid may be also used. Glycidyl adipate and glycidyl phthalate are typical examples.
Other suitable compounds are hydantoin epoxides, epoxidized polybutadiene and polyepoxide compounds which are obtained _ 9 _ l 3 3 5 3 9 5 by epoxidation of an olefinically unsaturated aliphatic compound.
Modified polyepoxides are understood to be polyepoxides in which some of the reactive groups have been reacted with a modifying compound.
Examples of modifying compounds are:
a) compounds containing carboxyl groups such as saturated or unsaturated monocarboxylic acids (for example benzoic acid, linseed fatty acid, 2-ethylhexanoic acid, versatic acid), aliphatic, cycloaliphatic and/or aromatic dicarboxylic acids of various chain lengths (for example adipic acid, sebacic acid, isophthalic acid or dimeric fatty acids), hydroxyalkylcarboxylic acids (for example lactic acid, dimethylolpropionic acid) as ~ell as polyesters containing carboxyl groups, or b) compounds containing amino groups, such as diethyl-amine or ethylhexylamine or diamines with secondary amino groups, for example N,N'-dialkylalkylenediamines such as dimethylethylenediamine, N,N'-dialkylpolyoxy-alkyleneamines such as N,N'-dimethylpolyoxypropylene-diamine, cyanoalkylated alkylenediamines such as bis-N,N'-cyanoethylethylenediamine, cyanoalkylated poly-oxyalkylene amines such as bis-N,N'-cyanoethylpolyoxy-propylenediamine, Polyaminoamides such as, for example, - 10 - l 335395 -versamides, in particular reaction products containing terminal amino groups, obtained from diamines (for example hexamethylenediamine), polycarboxylic acids, particularly dimeric fatty acids, and monocarboxylic acids, in particular fatty acids, or the reaction product of one mole of diaminohexane with two moles of a monoglycidyl ether or monoglycidyl ester, especially glycidyl esters of ~-branched fatty acids such as versatic acid, or c) compounds containing hydroxyl groups such as neopentyl-glycol, bis-ethoxylated neopentylglycol, neopentyl glycol hydroxypivalate, dimethylhydantoin-N,N'-diethanol, hexane-1,6-diol, hexane-2,5-diol, 1,4-bis(hydroxymethyl)-cyclohexane, 1,1-isopropylidene-bis(p-phenoxy)-2-propanol, trimethylolpropane, pentaerythritol or aminoalcohols such as triethanolamine, methyldiethanolamine or alkylketimines containing hydroxyl groups, such as aminomethylpropanediol-1,3-methylisobutylketimine or tris(hydroxymethyl)aminomethanecycl~hexanoneketimine, as well as polyglycol ethers, polyester polyols, poly-ether polyols, polycaprolactone polyols, polycapro-lactam polyols of various functionalities and molecular weights, or d) saturated or unsaturated fatty acid methyl esters which Z5 are transesterified with the hydroxyl groups of the epoxy resins in the presence of sodium methylate.
`~ Primary or secondary amines and their salts, salts of tertiary amines or mixtures of these compounds may be used as the component (B).
~ater-soluble amines are preferably used as the component (B). Examples of suitable amines are monoalkylamines and dialkylamines, such as methylamine, ethylamine, propyl-amine, butylamine, dimethylamine, diethylamine, dipropyl-amine, methylbutylamine etc. Alkanolamines, such as, for example, methylethanolamine and diethanolamine may also be used as components (B). Ketimines of polyamines with primary and secondary amino groups may also be used as the component (B). Furthermore, dialkylaminoalkyl-amines, such as, for example, dimethylaminoethylamine, diethylaminopropylamine and dimethylaminopropylamine, are also suitable as the component (B).
Low-molecular amines are used in most cases as the com-ponents tB). It is also possible, however, to use higher-molecular monoamines.
Secondary amines are preferably used as the components (B).
In many cases several different amines are used as the component (B).
The positive charges required for water dilutability and capacity to be electrically deposited may be imparted by protonation with water-soluble acids (for example boric 1 3353~5 acid, formic acid, lactic acid and, preferably, acetic acid) and/or by the use of amine salts as the components (B) in the binder molecule.
The cationic amine-modified epoxy resins used according to the invention are essentially free from epoxide groups, i.e. their epoxide group content is so low that cross-linking reactions via the epoxide groups cannot take place either before or after the deposition of the paint film.
The cationic amine-modified epoxy resins used according to the invention preferably do not contain any free epoxide groups.
The cationic amine-modified epoxy resins may be used both as non-self-crosslinking resins and as self-crosslinking resins. Self-crosslinking cationic amine-modified epoxy resins may be obtained, for example, by chemical modifica-tion of the cationic amine-modified epoxy resins. A self-crosslinking cationic amine-modified epoxy resin may be obtained, for example, by reacting the cationic amine-modified epoxy resin with a partly blocked polyisocyanate which has on average one free isocyanate group per mole-cule and whose blocked isocyanate groups lose their block-ing groups only at elevated temperatures.
Preferred electrocoating baths are obtained when non-self-crosslinking cationic amine-modified epoxy resins are used as resins capable of being cathodically deposited in com-bination with a suitable crosslinking agent.
Examples of suitable crossLinking agents are phenoplasts, polyfunctional Mannich bases, melamine resins, benzo-guanamine resins, blocked polyisocyanates and compounds containing at least two groups of the general formula R1-o-cO-The radical R1 denotes:
Rl = R20-C0-CH2-, R3-CHoH-CH2-, R4-CHoRS-CHoH-CH2-R = alkyl R3 = H, alkyl, R6-O-CH2- or R6-CO-0-CH2-R4 = H or alkyl RS = H, alkyl or aryl R6 = alkyl, cycloalkyl or aryl Preferred electrocoating baths are obtained when blockedpolyisocyanates and/or compounds containing at least two groups of the general formula R1-û-C0- are used as crosslinking agents.
Any polyisocyanates in which the isocyanate groups have been reacted with a compound in such a way that the blocked polyisocyanate formed is non-reactive toward hydroxyl and amino groups at room temperature, but becomes reactive at elevated temperatures, usually in the range from about 90C to about 300C, may be used as the blocked poly-isocyanates. Any organic polyisocyanates suitable for the crosslinking may be used for the preparation of the blocked polyisocyanates. Isocyanates containing about 1 33~3~S
3 to 36, in particular about 8 to about 15 carbon atoms, are preferred. Examples of suitable diisocyanates are hexamethylenediisocyanate, 2,4-toluylenediisocyanate, 2,6-toluylenediisocyanate and 1-isocyanatomethyl-5-iso-cyanato-1,3,3-trimethylcyclohexane. Ho~ever, it is also possible to employ polyisocyanates of higher isocyanate functionality. Corresponding examples are trimerized hexamethylenediisocyanate and trimerized isophoronediiso-cyanate. In addition, mixtures of polyisocyanates may also be used. The organic polyisocyanates which are suit-able as crosslinking agents for the invention may also be prepolymers derived, for example, from a polyol including a polyether polyol or a polyester polyol.
Any suitable aliphatic, cycloaliphatic or aromatic alkyl-monoalcohols may be used for the blocking of the polyiso-cyanates. Examples of these are aliphatic alcohols, such as methyl, ethyl, chloroethyl, propyl, butyl, amyl, hexyl, heptyl, octyl, nonyl, 3,3,5-trimethylhexyl, decyl and . lauryl alcohol; cycloaliphatic alcohols such as cyclo-pentanol and cyclohexanol; aromatic alkylalcohols suchas phenylcarbinol and methylphenylcarbinol.
Other suitable blocking agents are hydroxylamines such as ethanolamine, oximes such as methyl ethyl ketonoxime, acetone oxime and cyclohexanone oxime or amines such as dibutylamine and diisopropylamine. The above polyiso-cyanates and blocking agents may also be used, in suitable proportions, for the preparation of the partly blocked polyisocyanates referred to above.
Examples of compounds which contain at least two groups of the general formula R1-0-C0-, are bis(carbalkoxy-methyl) azelate, bis(carbalkoxymethyl) sebacate, bis-(carbalkoxymethyl) adipate, bis(carbalkoxymethyl) decanate,bis(carbalkoxymethyl) terephthalate, bis(2-hydroxybutyl) acelate (sic) and bis(2-hydroxyethyl) terephthalate.
The crosslinking agent is usually used in an amount from 5 to 60 % by weight, preferably 20 to 40 % by weight, based on the total amount of crosslinkable resin capable of being cathodically deposited contained in the electro-coating bath.
It is an essential part of the invention that in the process according to the invention electrocoating baths are employed which contain at least 7.5 % by weight of a polyoxyalkylenepolyamine or a mixture of several poly-oxyalkylenepolyamines of different chemical structures, the percentage by weight referring to the total amount of binders contained in the electrocoating bath.
The polyoxyalkylenepolyamines are understood to be com-pounds which contain both oxyalkylene groups as well as at least two amino groups, preferably at least two primary amino groups. The polyoxyalkylenepolyamines should have a number average molecular weight of about 137 to 3600, preferably 400 to 3000, particularly preferably 800 to 2500. Furthermore, the polyoxyalkylenepolyamines should have an amine equivalent weight of about 69 to about 1800, preferably 200 to 1500, particularly preferably 400 to 1Z50.
The polyoxyalkylenepolyamines preferably used have a chemical structure according to the general formula (I) H2N-CHR-CH2-O-(-CHR-CH2-0-)n-CH2-CHR-NH2 (I) in which R denotes H or an alkyl radical of 1 to 6 carbon atoms, preferably -CH3 n denotes S - 60, preferably 20 - 40.
Polyoxyalkylenepolyamines which have a chemical structure in accordance with the general formula (I), are disclosed in US-PS 3,236,895, column 2, lines 40-72. The processes for the preparation of these polyoxyalkylenepolyamines are disclosed in the patent examples 4, 5, 6 and 8 to 12 found in columns 4 to 9 of US-PS 3,236,895.
It is also possible to employ polyoxyalkylenepolyamines which contain different oxyalkylene groups, for example polyoxyalkylene polyamines which have a chemical structure in accordance with the general formula (II):
H2~-cH(cH3)-cH2-(o-cH(cH3)-cH2)n-(o~cH2-cH2-)m{}~H2-cH(c 3) 2 (II) in which n + m denotes S to 60, preferably 20 to 40 m denotes 1 to 59, preferably S to 30 n denotes 1 to 59, preferably 5 to 30.
It is also possible to use polyoxyalkylenepolyamine deriv-atives which are obtainable by the reaction of the poly-oxyalkylenepolyamines described in US-PS 3,236,895, column 2, lines 40-72, with acrylonitrile, followed by hydrogenation of the reaction product.
These derivatives have a chemical structure in accordance with the general structural formula (III):
~2N-(CH2)3-NH-CHR-CH2-0-(-CHR-CH2-0-)n-CH2-CHR-NH-(CH2)3-NH2 (III) in which 5 R denotes H or an alkyl radical of 1 to 6 carbon atoms, preferably -CH3 n denotes 5 to 60, prefereably 20 to 40.
It goes without saying that the electrocoating baths used according to the invention may also contain a mixture of - 18 - l 335395 - several polyoxyalkylenepolyamines of different chemical structures.
The polyoxyalkylenepolyamines or the polyoxyalkylene-polyamine mixtures may be incorporated in the electro-coating baths at any time during the preparation and evento the finished electrocoating baths. The polyoxyalkylene-polyamines or the polyoxyalkylenepolyamine mixtures are preferably added either to the aqueous dispersion or a pre-cursor of the aqueous dispersion which contains a resin 1û capabLe of being cathodically deposited and, optionally, a crosslinking agent and other customary additives such as, for example, antifoams etc. ~cf. page 4, lines 19 ff), or to the pigment paste or a precursor of the pigment paste (cf. page 4, lines Z6 ff).
The polyoxyalkylenepolyamine molecules are in all proba-bility protonized by the acid contained in the aqueous dispersion or the pigment paste.
However, it is also possible to add the corresponding polyoxyalkylenepolyamine or polyoxyalkylenepolyamine mixture in the protonized form to the aqueous dispersion under discussion or a precursor of this dispersion, or to the pigment paste or a precursor of the pigment paste.
The protonized polyoxyalkylenepolyamine or polyoxyalkylene-polyamine mixture may be obtained by the simple addition of a ~ronsted acid to the corresponding polyoxyalkylene-polyamine or polyoxyalkylenepolyamine mixture. The total ~ amount of ~ronsted acid contained in the finished electro-coating bath should be selected in such a manner that the pH of the electrocoating bath is between 4 and 8, pre-ferably between 5 and 7.5.
It is an essential part of the invention that the amount of polyoxyalkylenepolyamine or polyoxyalkylenepolyamine mixture contained in the electrocoating baths used accord-ing to the invention is at least 7.5 % by weight, the percentage by weight referring to the total amount of binders contained in the electrocoating bath. This means in other words that the electrocoating baths used accord-ing to the invention must contain at least 7.5 parts by weight of polyoxyalkylenepolyamine or polyoxyalkylene-polyamine mixture per 100 parts by weight of binder.
When electrocoating baths with a lower content of poly-oxyalkylenepolyamine or polyoxyalkylenepolyamine mixture are used, the resultant paint films exhibit considerably more and/or considerably more strongly pronounced sur-face defects than when the electrocoating baths accord-ing to the invention are used.
The upper limit of the amount of polyoxyalkylenepolyamineor polyoxyalkylenepolyamine mixture contained in the electrocoating baths used according to the invention is determined by the plasticizing effect of the added poly-oxyalkylenepolyamine or polyoxyalkylenepolyamine mixtureand is generally from 20 to 40 % by weight, the percent-age by weight referring to the total amount of binders contained in the electrocoating bath.
The electrocoating baths used according to the invention preferably contain 8 to 18, particularly preferably 10 to 15 % by weight of polyoxyalkylenepolyamine or poly-oxyalkylenepolyamine mixture, the percentage by weightreferring to the total amount of binders contained in the electrocoating bath.
The total amount of binders contained in the electrocoating bath is determined by adding the amount of resin capable of being cathodically deposited contained in the electro-coating bath, the amount of crosslinking agents option-ally contained in the electrocoating bath, the amount of ground resin contained in the electrocoating bath and the amount of resins which crosslink under the baking conditions which may or may not be additionally present in the electro-coating bath.
The solids content of the elec~rocoating baths used ac-cording to the invention is preferably 7 to 35 parts by weight, particularly preferably 12 to Z5 parts by weight.
The electrocoating bath is brought into contact with an electrically conducting anode and with the electrically conducting substrate connected as cathode. When electric current passes between the anode and the cathode, a highly adherant paint film is deposited on the cathode.
- 21 - f 335395 - The temperature of the electrocoating bath should be between 15 and 35C, preferably between 20 and 30C.
The applied voltage may fluctuate within a wide range and may be, for example, between two and one thousand S volt. However, typical operational voltages are between 50 and 500 volt. The current density is usually between about 10 and 100 ampere/mZ. The current density tends to drop in the course of the deposition.
When the deposition is completed, the coated object is rinsed and is then ready for baking.
The deposited paint films are generally baked at tempera-tures from 130 to 200C during a period of 10 to 60 minutes, preferably at 150 to 180C during a period from 15 to 30 minutes.
The process according to the invention may be employed for coating of any electrically conducting substrate, in particular, however, for coating of metals such as steel, aluminum, copper and the like.
The invention is explained in greater detail in the ex-amples below. All parts and percentages are parts and percentages by weight, unless expressly stated otherwise.
- 22 - l 3 3 5 3 9 5 - 1. Preparation of aqueous dispersions containing a resin capable of being cathodically deposited and a cross-linking agent.
1.1 Preparation of an amine-modified epoxy resin 1780 9 of Epikote 10011), 280 9 of dodecylphenol and 105 9 of xylene are placed in a reaction vessel and molten at 120C in an atmosphere of nitrogen.
Traces of water are subsequently removed in a slight vacuum. 3 9 of N,N-dimethylbenzylamine are then added, the reaction mixture is heated to 130C and kept at this temperature for about 3 h until the epoxide equivalent weight (EEW) has risen to 1162. The mixture is then cooled and 131 9 of hexylglycol, 131 9 of diethanolamine and 241 9 of xylene are then added in rapid succession. This causes a slight temperature rise. The reaction mix-ture is then cooled to 90C and further diluted by the addition of 183 9 of butylglycol and 293 9 of iso-butanol. When the temperature has dropped to 70C, 41 9 of N,N-dimethylaminopropylamine are added, the temperature is kept for 3 h and the mixture is then discharged.
The resin has a solids content of 70.2 ~ and a base content of 0.97 milliequivalents/gram.
1) An epoxy resin from Shell with an epoxide equivalent weight of 500.
i~ Tracie - ma~k 1.2 Preparation of a crosslinking agent 1.1Z9 9 of toluylene diisocyanate (commercial mixture of isomers consisting of the 2,4 and 2,6 isomers) and 490 9 of methyl isobutyl ketone are placed in a re-action vessel in an atmosphere of nitrogen. 0.6 9 of dibutyltin dilaurate and then, in small portions, Z90 g of trimethylolpropane are added with stirring in such a manner that with external cooling the internal temperature does not exceed 50C (duration about 2 h).
The reaction mixture is further stirred, while cool-ing, until the NCO equivalent weight has reached a value of 215. 675 9 of ethylene glycol monopropyl ether are then added dropwise at such a rate that the internal temperature does not exceed 100C. The temperature is then kept at 100C for 1 h, the mixture is diluted with 362 g of methyl isobutyl ketone and 10 g of n-butanol, and after brief cooling the mixture is discharged. The resin has a solids content of 71.8 %
(1 h at 130C) and a viscosity of 1.5 dPas (50 %
solution in methyl isobutyl ketone, measured in a plate-cone viscometer).
1.3 Preparation of the aqueous dispersions 1.3.1 Dispersion (I) 915 9 of resin according to procedure 1.1, 493 9 of crosslinking agent according to procedure 1.2 and 134 9 of a polyoxypropylenediamine of the formula 2 3 ) CH2 - ( -aCH2-CH ( CH3 ) ) -NH
x = 33.1 (JeffamineR D 2000, commercial product from Texaco Chemical Company) are mixed at room tempera-ture and stirred. As soon as the solution has become homogeneous, 2.2 g of an antifoam solution1) and 22 9 of glacial acetic acid are stirred in, and 674 9 of deionized water are added in 6 portions.
The mixture is then diluted with further 960 9 of deionized water added in small portions.
The resultant aqueous dispersion is freed from low-boiling solvents by vacuum distillation and subse-quently diluted with deionized water to a solids content of 33 %.
1.3.2 Dispersion (II) The procedure 1.3.1 is followed, except that 67 9 of polyoxypropylenediamine are used in place of 134 9 of polyoxypropylenediamine.
1) Surfynol (commercial product from Air Chemicals), .~ ~
a 50 % strength solution in ethylene glycol monobutyl ether T~G~- ma~ k - 1.3.3 Dispersion (III) Procedure 1.3.1 is followed, except that no poly-oxypropylenediamine is used. After vacuum distil-lation a correspondingly smaller amount of deionized water is added in order to adjust the solids content of 33 %.
2. Preparation of a pigment paste 2.1 Preparation of a ground resin according to DE-OS 3,422,457 640 parts of a diglycidyl ether based on bisphenol A
and epichlorohydrin with an epoxide equivalent weight of 485 and 160 parts of such diglycidyl ether with an epoxide equivalent weight of 189 are mixed at 100C.
452 parts of hexamethylenediamine are placed in a further vessel, heated to 100C and treated with 720 parts of the above hot epoxy resin mixture in the course of ~ne hour, gentle cooling being necessary in order to keep the temperature at 100C. After a further period of 30 minutes the excess hexamethyl-enediamine is removed while increasing the temperature and reducing the pressure, a final temperature of 205C
and a final pressure of 30 mbar being reached. 57.6 parts of stearic acid, 172.7 parts of dimeric fatty acid and 115 parts of xylene are then added. The water formed is then removed by azeotropic distillation at 175 to 180C
in the course of 90 min. 58 parts of butylglycol and - 26 - l 3 3 5 3 9 5 ~~ 3Z2 parts of isobutanol are then added. The product has a solids content of 70 % and a viscosity of 2240 mPas, measured at 75C in a plate-cone viscometer.
2.2 Preparation of the pigment paste 586 parts of the ground resin are thoroughly mixed with 1162 parts of deionized water and 22 parts of glacial acetic acid. The mixture is subsequently treated with 880 parts of TiO2, 250 parts of an ex-tender based on aluminum silicate, 53 parts of lead silicate and 10 parts of carbon black. This mixture is comminuted in a grinding unit to a Hegman fine-ness of less than 12 ~m. Deionized water is then added in order to reach the required paste consistency.
3. Preparation of electrocoating baths and deposited coatings according to the invention 700 parts of the pigment paste according to procedure 2.2 are added to 2200 parts by weight of the dispersions according to procedure 1.3, and the solids content of the bath is adjusted to 20 % by weight using de-ionized water. The deposition of the paint films is carried out for 2 minutes at 300 V on phosphated metal sheet. The bath temperature is 27C. The films are baked at 165C for 20 minutes.
- 27 - l 3 3 5 3 9 5 Electrocoating bath 1: Dispersion according to procedure 1.3.1 with paste according to procedure 2.2 Polyoxypropylenediamine content (based on the total amount of binders): 11.9 % by weight Electrocoating bath 2: Dispersion according to procedure 1.3.2 with paste according to procedure 2.2 Polyoxypropylenediamine content (based on the total amount of binders): 6.0 % by weight Electrocoating bath 3: Dispersion according to procedure 1.3.3 with paste according to procedure 2.2 Polyoxypropylenediamine content:
0 % by weight Deposition results Electrocoating bath 1 2 3 Film thickness (~m) 27 20 16 Flow-out1) 1.5 2.5 1.5 Craters/dm2 1 20 10 - za - 1 3 3 5 3 9 5 These films were then overcoated by a commercial aqueous filler and a white alkyd topcoat, and tested in a con-densed water static test for 240 h. The adhesion of the films was subsequently tested by the crosshatch test and S the Tesa puLl-off test.
Electrocoating bath 1 2 3 Adhesion1) 0.5 0.5 0,5 1)/ Rating 0 - 5 (good - poor)
Claims (18)
1. A process for coating an electrically conducting substrate, which process comprises:
(1) immersing the substrate in an aqueous electrocoating bath which contains a resin capable of being cathodically deposited;
(2) connecting the substrate as cathode;
(3) depositing a paint film on the substrate by the action of direct current;
(4) removing the substrate from the electrocoating bath and (5) baking the deposited paint film, wherein the electrocoating bath contains at least 7.5 % by weight of a polyoxyalkylenepolyamine or a mixture of two or more polyoxyalkylenepolyamines having different chemical structures, the percentage by weight being based on the total amount of binders contained in the electrocoating bath.
(1) immersing the substrate in an aqueous electrocoating bath which contains a resin capable of being cathodically deposited;
(2) connecting the substrate as cathode;
(3) depositing a paint film on the substrate by the action of direct current;
(4) removing the substrate from the electrocoating bath and (5) baking the deposited paint film, wherein the electrocoating bath contains at least 7.5 % by weight of a polyoxyalkylenepolyamine or a mixture of two or more polyoxyalkylenepolyamines having different chemical structures, the percentage by weight being based on the total amount of binders contained in the electrocoating bath.
2. The process as claimed in claim 1, wherein the electrocoating bath contains a cationic amine-modified epoxy resin as the resin capable of being cathodically deposited.
3. The process as claimed in claim 1 or 2, wherein the electrocoating bath contains a polyoxyalkylenepolyamine of the general formula (I):
(I) [in which R denotes H or an alkyl radical of 1 to 6 carbon atoms, and n denotes an integer of 5 to 60].
(I) [in which R denotes H or an alkyl radical of 1 to 6 carbon atoms, and n denotes an integer of 5 to 60].
4. The process as claimed in claim 3, wherein R denotes H
or CH3.
or CH3.
5. The process as claimed in claim 3, wherein n denotes an integer of 20 to 40.
6. The process as claimed in claim 1 or 2, wherein the aqueous electrocoating bath further contains a pigment or filler.
7. The process as claimed in claim 2, wherein the cationic amine-modified epoxy resin does not contain free epoxide groups.
8. The process as claimed in claim 7, wherein the cationic amine-modified epoxy resin is self-crosslinking.
9. The process as claimed in claim 7, wherein the cationic amine-modified epoxy resin is non-self-crosslinking; and the aqueous electrocoating bath further contains a crosslinking agent.
10. The process as claimed in claim 7, 8 or 9, wherein the polyoxyalkylenepolyamine has at least two primary amino groups, an average molecular weight of from about 137 to about 3,600 and an amine equivalent weight of from about 69 to about 1,800; and the polyoxyalkylenepolyamine is contained in an amount of 7.5 to 40 %
by weight based on the total amount of binders contained in the electrocoating bath.
by weight based on the total amount of binders contained in the electrocoating bath.
11. The process as claimed in claim 10, wherein the electrocoating bath contains a polyoxyalkylenepolyamine of the general formula (I):
(I) [in which R denotes H or an alkyl radical of 1 to 6 carbon atoms, and n denotes an integer of 5 to 60].
(I) [in which R denotes H or an alkyl radical of 1 to 6 carbon atoms, and n denotes an integer of 5 to 60].
12. The process as claimed in claim 11, wherein the polyoxyalkylenepolyamine is a polyoxypropylenediamine.
13. An aqueous electrocoating bath containing a resin capable of being cathodically deposited, wherein the said bath contains at least 7.5 % by weight of a polyoxyalkylenepolyamine or a mixture of two or more polyoxyalkylenepolyamines having different chemical structures, the percentage by weight being based on the total amount of binders contained in the electrocoating bath.
14. The electrocoating bath as claimed in claim 13, which contains a cationic amine-modified epoxy resin as the resin capable of being cathodically deposited.
15. The electrocoating bath as claimed in claim 13 or 14, which contains a polyoxyalkylenepolyamine of the general formula (I):
(I) [in which R denotes H or an alkyl radical of 1 to 6 carbon atoms, n denotes 5 to 60].
(I) [in which R denotes H or an alkyl radical of 1 to 6 carbon atoms, n denotes 5 to 60].
16. The electrocoating bath as claimed in claim 15, wherein R denotes H or CH3.
17. The process as claimed in claim 10, wherein n denotes an integer of 20 to 40.
18. An electrically conducting substrate having thereon a cathodically electrocoated and baked paint film of a binder resin that contains at least 7.5 % by weight (based on the binder resin) of a polyoxyalkylenepolyamine, the said paint film being formed by the process of claim 1.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE3801787A DE3801787A1 (en) | 1988-01-22 | 1988-01-22 | METHOD FOR COATING ELECTRICALLY CONDUCTIVE SUBSTRATES, SUBSTRATES COATED BY THIS METHOD, AND AQUEOUS ELECTRO Dipped Lacquer Baths |
| DEP3801787.3 | 1988-01-22 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1335395C true CA1335395C (en) | 1995-04-25 |
Family
ID=6345777
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000588746A Expired - Fee Related CA1335395C (en) | 1988-01-22 | 1989-01-20 | Process for coating electrically conducting substrates, substrates coated by this process and aqueous electrocoating baths |
Country Status (12)
| Country | Link |
|---|---|
| EP (2) | EP0386156A1 (en) |
| JP (1) | JPH083061B2 (en) |
| KR (1) | KR930008750B1 (en) |
| CN (1) | CN1026009C (en) |
| AT (1) | ATE78284T1 (en) |
| AU (2) | AU617152B2 (en) |
| BR (1) | BR8807879A (en) |
| CA (1) | CA1335395C (en) |
| DE (2) | DE3801787A1 (en) |
| ES (1) | ES2034140T3 (en) |
| WO (1) | WO1989006673A1 (en) |
| ZA (1) | ZA89252B (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3801786A1 (en) * | 1988-01-22 | 1989-07-27 | Basf Lacke & Farben | METHOD FOR COATING ELECTRICALLY CONDUCTIVE SUBSTRATES, SUBSTRATES COATED BY THIS METHOD, AND AQUEOUS ELECTRO Dipped Lacquer Baths |
| DE4015703A1 (en) * | 1990-05-16 | 1991-11-21 | Basf Lacke & Farben | PROCESS FOR COATING ELECTRICALLY CONDUCTIVE SUBSTRATES AND CATHODICALLY DETACHABLE WAFERRIGER ELECTROCOATING LACQUER |
| DE4401045C1 (en) * | 1994-01-15 | 1995-07-27 | Herberts Gmbh | Additives, their production and their use in cathodic electrodeposition baths |
| CN1230474C (en) * | 1996-07-23 | 2005-12-07 | 日本油漆株式会社 | Electrodeposition coating composition |
| JP4644330B2 (en) * | 1999-03-10 | 2011-03-02 | 関西ペイント株式会社 | Cationic electrodepositable resin composition |
| KR101113810B1 (en) * | 2009-11-27 | 2012-02-29 | 주식회사 유앤비오피씨 | Metal core pcb and method for manufacturing the same |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| ZA824373B (en) * | 1981-07-20 | 1984-02-29 | Ppg Industries Inc | Ungelled polyepoxide-polyoxyalkylenepolyamine resins,aqueous dispersions thereof,and their use in cationic electrodeposition |
| US4423166A (en) * | 1981-07-20 | 1983-12-27 | Ppg Industries, Inc. | Ungelled polyepoxide-polyoxyalkylenepolyamine resins, aqueous dispersions thereof, and their use in cationic electrodeposition |
| ATE29145T1 (en) * | 1985-02-27 | 1987-09-15 | Corona Peintures | REACTION PRODUCTS OF POLYOXYALKYLENEPOLYAMINE AND THEIR USE IN CATIONIC ELECTROCOAT. |
| GB2173802B (en) * | 1985-04-18 | 1989-12-28 | Ici Plc | Non-gelled amine-epoxide reaction products and coating compositions comprising acid salts thereof |
| DE3518770A1 (en) * | 1985-05-24 | 1986-11-27 | BASF Lacke + Farben AG, 4400 Münster | WATER-DISCOVERABLE BINDING AGENTS FOR CATIONIC ELECTRO-DIP COATINGS AND METHOD FOR THEIR PRODUCTION |
-
1988
- 1988-01-22 DE DE3801787A patent/DE3801787A1/en not_active Withdrawn
- 1988-12-15 EP EP89902202A patent/EP0386156A1/en active Pending
- 1988-12-15 ES ES198888120996T patent/ES2034140T3/en not_active Expired - Lifetime
- 1988-12-15 EP EP19880120996 patent/EP0324951B1/en not_active Expired - Lifetime
- 1988-12-15 DE DE8888120996T patent/DE3872867D1/en not_active Expired - Lifetime
- 1988-12-15 WO PCT/EP1988/001164 patent/WO1989006673A1/en not_active Application Discontinuation
- 1988-12-15 AT AT88120996T patent/ATE78284T1/en active
- 1988-12-15 AU AU30529/89A patent/AU617152B2/en not_active Ceased
- 1988-12-15 AU AU30529/89A patent/AU3052989A/en active Granted
- 1988-12-15 BR BR888807879A patent/BR8807879A/en not_active IP Right Cessation
- 1988-12-15 JP JP1502059A patent/JPH083061B2/en not_active Expired - Lifetime
- 1988-12-15 KR KR1019890701740A patent/KR930008750B1/en not_active IP Right Cessation
-
1989
- 1989-01-12 ZA ZA89252A patent/ZA89252B/en unknown
- 1989-01-20 CN CN89100299A patent/CN1026009C/en not_active Expired - Fee Related
- 1989-01-20 CA CA000588746A patent/CA1335395C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| DE3801787A1 (en) | 1989-07-27 |
| CN1026009C (en) | 1994-09-28 |
| EP0324951A1 (en) | 1989-07-26 |
| ATE78284T1 (en) | 1992-08-15 |
| ZA89252B (en) | 1989-10-25 |
| BR8807879A (en) | 1990-10-09 |
| ES2034140T3 (en) | 1993-04-01 |
| KR930008750B1 (en) | 1993-09-13 |
| DE3872867D1 (en) | 1992-08-20 |
| AU617152B2 (en) | 1991-11-21 |
| KR900700552A (en) | 1990-08-16 |
| JPH083061B2 (en) | 1996-01-17 |
| WO1989006673A1 (en) | 1989-07-27 |
| AU3052989A (en) | 1989-08-11 |
| EP0324951B1 (en) | 1992-07-15 |
| CN1039074A (en) | 1990-01-24 |
| JPH02503573A (en) | 1990-10-25 |
| EP0386156A1 (en) | 1990-09-12 |
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