Classifications

• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D1/00—Electroforming
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D13/00—Electrophoretic coating characterised by the process
  • C25D13/04—Electrophoretic coating characterised by the process with organic material
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D13/00—Electrophoretic coating characterised by the process
  • C25D13/22—Servicing or operating apparatus or multistep processes
  • C25D13/24—Regeneration of process liquids
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D13/00—Electrophoretic coating characterised by the process
  • C25D13/10—Electrophoretic coating characterised by the process characterised by the additives used
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D13/00—Electrophoretic coating characterised by the process
  • C25D13/22—Servicing or operating apparatus or multistep processes

Definitions

• the present invention relates to a method for producing an anodic Electrocoating (ATL) using a low-solvent / free Electrocoating bath (ATL bath), being used to maintain the bath and Electrodialysis in the ETL bath is not required for the coating parameters. It is also not necessary, therefore regularly discard ultrafiltrate.
• ATL bath low-solvent / free Electrocoating bath
• anodic electrocoating is in the literature described and has prevailed in practice. Even after the introduction of the cathodic electrocoating (KTL), is the anodic electrocoating still a widespread coating process, especially for coating of industrial goods. On the one hand, this is due to the large number available anodic coating systems, on the other hand to the good level of today anodic coating materials. Certain materials, such as Aluminum more advantageous with anodic than with cathodic To coat electrocoat compositions.
• the anodic Electrocoating is a workpiece with an electrically conductive surface Metal or from electrically conductive plastic or from an electrically conductive coating provided substrate in an aqueous ATL bath and as Anode connected to a DC power source.
• the ATL bath consists of an aqueous dispersion, e.g. Suspension or emulsion or from an aqueous solution of one or more binders which at least partially by salt formation with organic or inorganic Neutralizing agents have been made water-dispersible or water-soluble pigments, fillers, additives and other auxiliaries dispersed therein.
• aqueous dispersion e.g. Suspension or emulsion or from an aqueous solution of one or more binders which at least partially by salt formation with organic or inorganic Neutralizing agents have been made water-dispersible or water-soluble pigments, fillers, additives and other auxiliaries dispersed therein.
• the polymer particles migrate aqueous dispersion of the ATL bath to the anode and react there with the ions occurring at the same time water electrolysis to the water-insoluble polymer, which coagulates from the aqueous phase and itself deposits with the additives dispersed therein on the anode as a lacquer film.
• the usual ATL baths are operated continuously, i.e. in one with the Electrocoating tanks filled with coating agent become those described above Dipped and coated substrates. This makes the ATL bath solid withdrawn and at the same time released neutralizing agent in the ATL bath. To the It is to keep coating parameters and the quality of the coating constant required to compensate for the withdrawn solid from the ATL bath Add refill material with an increased solid content and for maintenance of the desired MEQ value released neutralizing agent in the ATL bath compensate.
• the object was therefore to develop a process for the preparation of an aqueous Low solvent or solvent free coating composition for the to provide anodic electrocoating when used for Coating of conductive substrates in an ATL bath to maintain the Bath and coating parameters a removal of the during coating not released neutralizing agent by an electrodialysis device is required and a large amount of ultrafiltrate is not regularly discarded must become.
• this object was achieved in that the in the electrocoating coating material used and the neutralizing agent released, an anodic refill consisting from a pigment-free aqueous binder component and a pigment-containing one aqueous paste resin component, which is so far neutralized is that when it enters the ATL bath it releases the neutralizing agent released there compensated and still contains only small amounts of organic solvents.
• the solids content of components A) and B) can, for example, according to DIN EN ISO 3251 at 30 '180 ° C.
• the solids content of the component A) is preferably 45 to 65% by weight.
• the solids content of component B) is preferably 60 to 73% by weight.
• the MEQ value of component A) is preferably 20 to 35, the MEQ value of Component B) is preferably 5 to 10.
• the MEQ value is a measure of the Neutralizing agent content in a water-based paint. It is defined as the amount of Millie equivalents of the neutralizing agent based on 100g solids.
• the organic solvent content of component A) is preferably 0,4 0.4 %
• By weight of component B) is preferably 0,5 0.5% by weight.
• the mixing ratio of component (A) to component (B) is 1: 1 to 4 : 1, preferably from 2: 1 to 3.5: 1 based on the weight of the respective aqueous Component.
• the mixture has a solids content of 45 to 73 wt .-%, a Solvent content of at most 0.75% by weight and an MEQ value that is around 50 to 70 %, preferably by 60 to 70% lower than the MEQ value of the ATL bath in coatable condition.
• Component (A) contains the binder or binders of the aqueous coating agent, and optionally a biocidal component and if necessary Crosslinking agents and optionally emulsifiers, layer formers, others Additives such as Neutral resins, common paint additives such as light stabilizers and optical brighteners.
• Component (B) contains one or more paste resin (s), pigments and / or Fillers, optionally a biocidal component and if necessary Crosslinking agents, and optionally layer formers and customary paint additives and further additives, for example as contained in component (A) can.
• binder systems can be used as suitable binders of component (A) an acid number from 20 to 150, preferably from 20 to 120 and a hydroxyl number from 20 to 150, preferably from 60 to 120, as used for aqueous Coating systems, especially known for anodic electrocoating are.
• polyester, polyacrylate and polyurethane resins include, for example, polyester, polyacrylate and polyurethane resins; modified polyester or polyurethane resins, e.g. Alkyd resins, urethanized Polyester resins or acrylated polyester or polyurethane resins, as well as mixtures these resins. Polyester resins are preferred.
• Suitable polyester resins in component (A) are, for example carboxyl-containing and hydroxyl-containing polyesters with an acid number of 20 up to 150 and a hydroxyl number from 20 to 150. They are according to the, the expert known methods by reacting polyhydric alcohols and polyvalent carboxylic acids or carboxylic anhydrides, and optionally aromatic and / or aliphatic monocarboxylic acids. The required Hydroxyl group content is determined in a manner known per se by suitable choice of Type and proportions of the starting components set.
• the Carboxyl groups can be formed, for example, from half-esters prefabricated. Hydroxyl group-containing polyester resin with acid anhydrides be introduced. The incorporation of carboxyl groups can also be done, for example, by Use of hydroxycarboxylic acids in the polycondensation reaction respectively.
• the dicarboxylic acids and the polyols can be aliphatic or aromatic Be dicarboxylic acids and polyols.
• the low molecular weight polyols used to make the polyesters are e.g. Diols such as alkylene glycols, for example ethylene glycol, butylene glycol, hexanediol, hydrogenated bisphenol A and 2,2-butyl-ethyl-propanediol, neopentyl glycol and / or other glycols such as dimethylolcyclohexane. But it can also be more functional or mixtures of higher and monofunctional OH components such as e.g.
• Polyether the condensates of Are glycols with alkylene oxides
• Monoethers of glycols such as diethylene glycol monoethyl ether, Tripropylene glycol monomethyl ether can be used.
• the acid component of the polyester preferably consists of low molecular weight Dicarboxylic acids or their anhydrides with 2 to 18 carbon atoms in the molecule.
• Suitable acids are, for example, phthalic acid, isophthalic acid, terephthalic acid, Tetrahydrophthalic acid, hexahydrophthalic acid, adipic acid, azeleic acid, sebacic acid, Fumaric acid, maleic acid, glutaric acid, succinic acid, itaconic acid and / or 1,4-cyclohexanedicarboxylic acid.
• phthalic acid isophthalic acid, terephthalic acid, Tetrahydrophthalic acid, hexahydrophthalic acid, adipic acid, azeleic acid, sebacic acid, Fumaric acid, maleic acid, glutaric acid, succinic acid, itaconic acid and / or 1,4-cyclohexanedicarboxylic acid.
• their methyl esters can also be used or anhydrides, if they exist, can be used.
• the polyester resins can also, for example, by incorporating unsaturated ones Compounds, compounds containing isocyanate groups or by lap or Graft polymerization can be modified with ethylenically unsaturated compounds.
• Preferred polyesters in component (A) are, for example, carboxyl-containing polyesters with an acid number from 20 to 120, a hydroxyl number from 20 to 150, preferably from 60 to 120. They are, for example, reaction products of two and / or polyhydric aliphatic or cycloaliphatic saturated alcohols, aliphatic , cycloaliphatic and / or monocyclic aromatic dibasic or polybasic polycarboxylic acids and optionally linear or branched, saturated or unsaturated aliphatic and / or cyclialiphatic C 3 to C 20 monoalcohols or monocarboxylic acids.
• the quantitative ratios of the starting components are calculated from the molar ratios. which lead to the desired acid numbers and hydroxyl numbers of the resin. The selection of the individual starting components is known to the person skilled in the art, taking into account the objective.
• the number average molecular weight Mn, measured against polystyrene as Calibration substance is, for example, 1000 to 6000, preferably 2000 to 4000. Oil-free polyesters containing carboxyl groups, such as those e.g. in DE-A-32 47 756 are described.
• polyesters preferably contain 0.3 to 3.0, particularly preferably 0.5 to 2.5 Milliequivalents of aliphatic, cycloaliphatic and / or monocyclic aromatic Dicarboxylic acids condensed per gram of resin. From three or more basic cyclic carboxylic acids are expediently 0.8 to 2.0, preferably 0.9 to 1.8, more preferably 1.1 to 1.5 millimoles per gram of resin over only one Carboxyl group bound to the polyester. As polycarboxylic acids, three and / or polybasic polycarboxylic acids used, preferably three and / or four-base acids. These polyesters are produced in a manner known per se Way by polycondensation of the starting materials, whereby to avoid Turbidity and gel formation is preferably carried out gradually.
• the esterification of preferably aromatic and cycloaliphatic dicarboxylic acids, which cannot form an intramolecular anhydride is preferably carried out with dialcohols, which are either secondary OH groups or sterically handicapped by ⁇ substitution contain primary OH groups, with an OH group containing excess alcohol Polyester is created.
• the alcohols preferably contain 2 to 21, particularly preferably 4 to 8 carbon atoms.
• the dicarboxylic acids preferably contain 5 up to 10 carbon atoms, particularly preferably 6 carbon atoms.
• Examples include isophthalic acid, terephthalic acid, 1,3- and 1,4-cyclohexanedicarboxylic acid or alkyl-substituted dicarboxylic acids with Butylisophthalic. Isophthalic acid is particularly preferred. To achieve Branches can be replaced by a corresponding one instead of some of the dicarboxylic acids Amount of tricarboxylic acid such as trimellitic anhydride in the resin molecule be condensed. On the other hand, dimethyl esters such as Dimethyl terephthalate or dimethyl 1,4-cyclohexanedicarboxylate Transesterification, optionally in the presence of transesterification catalysts, in the Polyester are introduced.
• dimethyl esters such as Dimethyl terephthalate or dimethyl 1,4-cyclohexanedicarboxylate Transesterification, optionally in the presence of transesterification catalysts, in the Polyester are introduced.
• Preferred dialcohols are neopentyl glycol, Hydroxypivalic acid neopentyl glycol ester, hexanediol-2,5, 1,4-bis (hydroxymethyl) cyclohexane, 1,1-isopyrilidine-bis- (p-phenoxy) -2-propanol, 2,2,4-trimethylpentanediol-1,3, and mixtures from that.
• the glycidyl ester of ⁇ -branched can also be used as the dialcohol Fatty acids, such as versatic acid, are used because the fatty acid is stable to hydrolysis the molecular structure is built in.
• the use of Epoxy resins possible, whose epoxy groups have been reacted with monoalcohols are.
• a partial use of polyols with more than two OH groups such as Trimethylolpropane or pentaerythritol is used to set suitable OH numbers and Viscosities possible.
• This esterification (first stage) is azeotropic or in a known manner Melt made at elevated temperature (above 190 ° C) and delivers a clear Product with an acid number from 0 to 50, preferably from 5 to 25 and a viscosity from 200 to 3000 mPas at 25 ° C, measured in a 75% butyl glycol solution.
• the OH group-containing polyester carboxyl groups are additionally introduced.
• an aromatic or cycloaliphatic dicarboxylic acid preferably by using defunctionalization a long chain, aliphatic hydrophobic monoalcohol from one Polycarboxylic acid with three or four carboxyl groups such as Trimesic acid, hemellitic acid, prehnitic acid and mellophanoic acid has arisen.
• the process is particularly simple when using anhydride-containing ones Compounds such as trimellitic anhydride, pyromellitic anhydride or corresponding hydrogenated ring systems, and cyclopentanetetracarboxylic anhydride or pyrazine tetracarboxylic anhydride.
• the polycarboxylic acids can, for example, in a two-pot process be implemented stoichiometrically with so much monoalcohol that a dicarboxylic acid is retained, which then contributes to the OH group-containing polyester Temperatures of about 150 to 190 ° C is added.
• Straight-chain and / or, for example, can be used as monoalcohols branched saturated and / or unsaturated, primary, secondary and / or tertiary, preferably primary and / or secondary alcohols. Mixtures, in particular isomeric mixtures of these alcohols can be used. Are preferred aliphatic C6 to C18 monoalcohols and benzyl alcohol and its Alkyl substitution. Branched-chain C8 bis are particularly preferred C13 iso-monoalcohols. Particularly half-esters that are stable to hydrolysis are produced by Use of ⁇ -branched monoalcohols or secondary monoalcohols such as Get cyclohexanol or secondary methyl octyl alcohol. By building the Resin ensures that hydrolysis may occur Fission products (monoalcohol and trimellitic acid monoesters) without interference be deposited electrophoretically with the film.
• the incorporation of carboxyl groups can also, for example, by using Hydroxycarboxylic acids such as e.g. Dimethylolpropionic acid in the Polycondensation reaction take place, the free carboxyl group in general does not participate in the polycondensation reaction because of the steric hindrance, so that the incorporation of this acid takes place exclusively via the hydroxyl groups.
• Hydroxycarboxylic acids such as e.g. Dimethylolpropionic acid in the Polycondensation reaction take place
• the free carboxyl group in general does not participate in the polycondensation reaction because of the steric hindrance, so that the incorporation of this acid takes place exclusively via the hydroxyl groups.
• the molar ratios of the overall formulation for the production of the polyester are so chosen to achieve a viscosity suitable for the respective application becomes. It is, for example, about 200 to 3000, preferably 250 to 2000 and particularly preferably 300 to 1500 mPas, measured 50% in butyl glycol at 25 ° C. Like molecular weight, it can be made by mixing resins with higher ones and lower viscosity, or higher and lower molecular weight can be set.
• the upper limit of the acid number is preferably below 100, particularly preferably under 60; the lower limit of the acid number is preferably above 35, particularly preferably over 40.
• the carboxyl-containing polyester contains at least one.
• the finished Resin has a hydroxyl number of about 20 to 150, preferably from 60 to 120. There will be Resins preferred which have a relatively high hydroxyl number with a low acid number exhibit.
• the polycondensation takes place, for example, azeotropically or in the melt for example at reaction temperatures between 160 to 240 ° C, preferred between 160 to 210 ° C.
• After reaching the desired final resin values regarding Viscosity and acid number is cooled to a temperature such that a Product with a viscosity that ensures the incorporation of water. In practice, this means that the melt viscosity achieved does not exceed 40,000 mPa.s should lie. This can be achieved by cooling to a suitable temperature. Unless you are working under pressure, this is up to about 100 ° C.
• the Neutralized polycondensation product For transfer to an aqueous solution or dispersion, the Neutralized polycondensation product.
• the neutralizing agent Polycondensation resin can be added before or during the addition of water to it can also be placed in the water in which the polycondensation resin is dispersed.
• high-speed stirring disc devices, Rotor / stator mixers or high pressure homogenizers are used.
• organic solvents are removed by distillation.
• neutralizing agents for example ammonia; primary, secondary and tertiary amines such as diethylamine, Triethylamine, morpholine; Alkanolamines such as diisopropanolamine, Dimethylaminoethanol, triisopropanolamine, dimethylamino-2-methylpropanol; quaternary ammonium hydroxides or possibly also small amounts of Alkylene polyamines such as ethylenediamine. Mixtures of these can also be used Neutralizing agents can be used.
• the stability of the aqueous Dispersion can be influenced.
• the amount of neutralizing agent is chosen so that the MEQ value of the mixture of component (A) and component (B) is around 50 is up to 70% below the MEQ value of the ATL bath.
• Suitable polyacrylate resins in component (A) are, for example copolymers containing carboxyl groups and / or sulfonic acid groups with a Acid number from 20 to 150 and a number average molecular weight Mn of 1000 up to 10,000.
• Suitable monomers containing acid groups are in principle all olefinic unsaturated polymerizable compounds containing at least one carboxyl and / or Have sulfone group, such as olefinically unsaturated mono or Dicarboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, fumaric acid, Maleic acid, itaconic acid or the half esters of fumaric acid, maleic acid and Olefinically unsaturated itaconic acid or sulfonic acid groups Compounds such as 2-acrylamido-2-methylpropanesulfonic acid or any mixtures of such olefinically unsaturated acids. Particularly preferred are acrylic acid and methacrylic acid.
• the copolymers can lacquer in addition to the monomers containing acid groups contain further functional monomers with which e.g. crosslinking reactions have it carried out. Both self-crosslinking of the copolymers and External networking with other components in the paint respectively.
• Examples of such functional groups are hydroxy, amino, amido, keto, Aldehyde, lactam, lactone, isocyanate, epoxy and silane groups.
• olefinically Unsaturated monomers which carry such functional groupings are known. Hydroxy and epoxy groups are particularly preferred.
• all non-functional olefinic unsaturated monomers can be used.
• Suitable non-functional monomers are, for example, esters of acrylic and Methacrylic acid, the alcohol components of which contain 1 to 18 carbon atoms, Vinyl aromatics, vinyl esters of aliphatic monocarboxylic acids, acrylic and Methacrylonitrile.
• the copolymers can be prepared by conventional polymerization Procedures are carried out. The production of the Copolymers in organic solution. Continuous or are possible discontinuous polymerization processes.
• Aromatics, esters, ethers and ketones can be used as solvents.
• Prefers glycol ethers are used.
• the copolymerization generally takes place at temperatures between 80 to 180 ° C using conventional initiators such as aliphatic Azo compounds or peroxides. To regulate the molecular weight of the Polymers can be used with conventional regulators. After polymerization is complete the copolymers, as described for the polycondensation resins, neutralized and transferred to an aqueous solution or dispersion, wherein if necessary, the organic solvent can be removed by distillation.
• Suitable polyurethane resins in component (A) are, for example, anionic Polyurethane resins, the carboxylic, sulfonic and / or present in salt form Contain phosphonic acid groups. They are made in a manner known per se Polyols, polyisocyanates and optionally chain extenders.
• the polyurethane resins can be used both in substance and in organic solvents. which cannot react with isocyanates. You will like the polycondensation resins described, by neutralizing the acid groups in the aqueous phase transferred. In many cases, it is useful to To produce polyurethane resins in stages.
• the polyols used to prepare the prepolymer can be low and / or be high molecular weight and also contain anionic groups.
• Low molecular weight polyols preferably have a number average molecular weight Mn of 60 to 400 and can contain aliphatic, alicyclic or aromatic groups. she up to 30% by weight of the total polyol components can be used.
• Suitable low molecular weight polyols are, for example, diols, triols and polyols, such as ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,2-butylene glycol, 1,6-hexanediol, trimethylolpropane, Castor oil or hydrogenated castor oil, pentaerythritol, 1,2-cyclohexanediol, 1,4-cyclohexanedimethanol, Bisphenol A, bisphenol F, neopentyl glycol, Hydroxypivalic acid neopentyl glycol ester, hydroxyethylated bisphenol A, hydrogenated Bisphenol A and mixtures of these polyols.
• diols such as ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propane
• High molecular weight polyols consist of linear or branched polyols with one OH number from 30 to 150. You can up to 97 wt .-% of the total Polyol components are used. These are preferably saturated or unsaturated polyester and / or polyether diols and / or polycarbonate diols a molecular weight Mn of 400 to 5000 or mixtures thereof.
• Suitable linear or branched polyether diols are, for example Poly (oxyethylene) glycols, poly (oxypropylene) glycols and / or Poly (oxybutylene) glycols.
• Polyesters are preferred and are prepared in a known manner by esterification of Dicarboxylic acids or their anhydrides made with diols.
• To branch To produce polyesters, polyols or Polycarboxylic acids with a higher functionality are used.
• the groups capable of forming anions can originate from the polyester or they are introduced into the prepolymer by using compounds, the two H-active groups reacting with isocyanate groups and at least one for Group capable of anion formation.
• Suitable with isocyanate groups reacting groups are in particular hydroxyl groups and primary and / or secondary amino groups.
• Groups that are capable of forming anions for example carboxyl, sulfonic acid and / or phosphonic acid groups.
• examples for such compounds are dihydroxycarboxylic acids, such as dihydroxypropionic acid, Dihydroxybutyric acid, dihydroxysuccinic acid, diaminobenzoic acid and preferred ⁇ , ⁇ -dimethylolalkanoic acid such as e.g. Dimethylolpropionic.
• Aliphatic, cycloaliphatic and / or aromatic are suitable as polyisocyanates
• the polyisocyanate component used to prepare the prepolymer can also contain small amounts of higher functional polyisocyanates.
• the prepolymer is advantageously prepared in the presence of Catalysts, such as Organotin compounds or tertiary amines performed.
• the polyurethane resin is transferred into the aqueous phase as in the case of Described polyester resins by neutralization of the acid group Polyurethane resin with a basic neutralizing agent.
• basic Neutralizers are those for neutralizing the polyester resins above . described
• the coating composition of the invention is crosslinked preferably when baked by reaction with a crosslinking component.
• Crosslinking components are familiar to the person skilled in the art. examples are Aminoplast resins, in particular melamine-formaldehyde resins; phenolic resins; blocked polyisocyanates or transesterification crosslinkers such as polyester or Polyurethane esters with hydroxyalkyl ester groups, acetoacetic acid or malonic acid alkyl ester derivatives, Tris (alkoxycarbonylamino) triazine derivatives and mixtures of these crosslinking components, with or without the action of catalysts highly crosslinked coatings can result.
• Blocked polyisocyanates prefers.
• the blocked polyisocyanates contain on average more than one isocyanate group, preferably at least two isocyanate groups per molecule. They are said to be in the watery Phase stable at about neutral to weakly basic pH. at Split heat from about 100 ° C to 200 ° C and with the im Crosslink resin dressings existing reactive hydroxyl and / or carboxyl groups.
• polyisocyanates individually or as a mixture in blocked form Any organic di- and / or are suitable Polyisocyanates with aliphatic, cycloaliphatic, araliphatic and / or aromatically bound, free isocyanate groups.
• polyisocyanates which contain about 3 to 36, particularly preferably 8 to 15 Contain carbon atoms.
• suitable diisocyanates are Tolylene diisocyanate, diphenylmethane diisocyanate and in particular Hexamethylene diisocyanate, tetramethylxylylene diisocyanate, isophorone diisocyanate, Dicyclohexylmethane diisocyanate and cyclohexane diisocyanate.
• Monofunctional compounds with active hydrogen, which are used to block the Polyisocyanates can be used are common.
• CH-acidic Compounds such as acetylacetone; CH-acidic esters such as alkyl acetoacetate, malonates; (cyclo) aliphatic alcohols such as n-butanol, 2-ethylhexanol, cyclohexanone; Glycol ethers such as butyl glycol, butyl diglycol; Phenols such as cresol, tert-butylphenol; Diamino alcohols such as dimethylaminoethanol; Oximes like butanone oxime, Acetone oxime, cyclohexanone oxime; Lactams such as ⁇ -caprolactam or pyrrolidone-2; imides; hydroxyalkyl; Hydroxamic acids and their esters; Pyrazole become.
• the polyisocyanates can be the same or different within one molecule Blocking agents must be blocked. Mixtures of the same or differently blocked polyisocyanates can be used.
• the melamine-formaldehyde resins crosslink with the hydroxyl groups Polyester resin with formation of ether groups.
• these crosslinkers in accordance with known technical processes in the presence of Alcohols such as methanol, ethanol, propanol, butanol or hexanol with aldehydes, especially formaldehyde, condensed triazines such as melamine or benzoguanamine.
• methanol-etherified melamine resins such as Cymel 325, Cymel 327, Cymel 350, Cymel 370, Maprenal MF 927; Butanol or Isobutanol etherified melamine resins such as Setamin US 138 or Maprenal MF 610; mixed etherified melamine resins, and in particular um Hexamethylol melamine resins such as e.g. Cymel 301 or Cymel 303.
• component (A) Because of the low content of organic solvent in component (A) it is expedient for component (A) to be a customary biocidal component Prevention of infestation with microorganisms such as bacteria, yeast, algae or Add mushrooms, such as formaldehyde depot products. phenolic Compounds, organic sulfur compounds or oxidizing agents.
• components (A) can also the usual auxiliaries and additives are added in the usual amounts, for example optical brighteners such as derivatives of stilbene, coumarin, 1,3-diphenylpyrazoline, Naphthalimide, benzoxazole and thiophenbenzoxazole, usual Catalysts as known to the person skilled in the art for the respective crosslinking systems are; ethoxylated or propoxylated derivatives of substituted phenols or Fatty alcohols with more than 10 carbon atoms as layer formers.
• optical brighteners such as derivatives of stilbene, coumarin, 1,3-diphenylpyrazoline, Naphthalimide, benzoxazole and thiophenbenzoxazole
• Catalysts as known to the person skilled in the art for the respective crosslinking systems are; ethoxylated or propoxylated derivatives of substituted phenols or Fatty alcohols with more than 10 carbon atoms as layer formers.
• the aqueous pigmented component (B) contains one or more paste resins, Pigments and / or fillers, neutralizing agents, water and appropriately one biocidal component and optionally crosslinking agents and / or paint Additives and additives, such as those described for component (A) are.
• the layer formers can e.g. in amounts up to 10% by weight, based on the Solids of the components, components (A) and / or (B) are added.
• the addition can be made to components (A) / or (B) or to the aqueous ones Components (A) and / or (B) or in the coatable electro dip lacquer bath respectively.
• the layer formers are preferred in the binders of the components (A) and / or (B) added before their conversion into the aqueous dispersion.
• Suitable paste resins are polyester resins, polyurethane resins, polyacrylate resins and Aminoplast resins as described for component (A). To be favoured Polyester urethane resins.
• a particularly preferred embodiment is, for example, OH groups urethanized oil-free polyesters with an acid number of 10 to 50 and a number average the molecular weight (Mn) from 2000 to 20000.
• Such polyester urethane resins are obtained, for example, by implementing one or more of Carboxyl-free polyester polyol (s) with an OH number of 35 to 200 and a number average molecular weight of 500 to 5000 with 2 to 30% by weight on the polyester polyol, on low molecular weight diols with a molecular weight of 60 to 350, some of the low molecular weight diols at least one for anion formation contains capable acid group, and with 0 to 6 wt .-%, based on the Polyester polyol, on low molecular weight triplets with a molecular weight of 60 to 350 with one or more diisocyanates, in the ratio of the OH groups of Polyester polyol, diol and triol to the NCO groups of the diisocyanate of over
• the polyester urethane resin is produced, for example, at Temperatures from 20 to 150 ° C, preferably from 45 to 90 ° C, optionally below Addition of catalysts such as organotin compounds or tertiary amines.
• catalysts such as organotin compounds or tertiary amines.
• the polyaddition is mixed in with good stirring the melt or after dilution with dry solvents that are not compatible with the React isocyanate group carried out. It runs until practically everyone Isocyanate groups are implemented. On the other hand, the reaction can also be gradual be made.
• Polyols have one or more hydroxyl groups at the chain end. at the step-by-step production can also be carried out in a different order.
• the anionic diol such as dimethylol propionic acid
• organic solvent which does not react with the isocyanate groups
• polyester and low molecular weight anion-free diol and / or triol is implemented.
• the polyaddition may optionally be desired Reaction status through monofunctional additives such as butanone oxime, dibutylamine or alcoholic solvents.
• monofunctional additives such as butanone oxime, dibutylamine or alcoholic solvents.
• Suitable solvents are, for example, dimethylformamide, Dimethylacetamide, 1-methyl-2-pyrrolidone, acetonitrile, tetrahydrofuran, dioxane, Esters such as ethyl acetate, but also ketones such as acetone, fully etherified mono- or Diglycols of ethylene glycol or propylene glycol, as well as with methoxy groups substituted ketones.
• polyester urethane resin Before the polyester urethane resin is transferred to the aqueous phase, the latter where appropriate, the aforementioned biocides, crosslinking agents and / or customary paints Additives and additives added. Then the transfer into the aqueous takes place Phase as described for component (A).
• aqueous component (B) For pigmenting the aqueous component (B), customary pigments, Fillers, corrosion inhibitors and paint aids are used as long as they are with water in a weakly basic to neutral pH-value no disturbing reactions enter and do not bring in water-soluble interfering foreign ions.
• Suitable pigments are, for example, inorganic pigments, e.g. White pigments like titanium dioxide.
• Lead carbonate, lead sulfate, tin oxide, Antimony oxide colored inorganic pigments such as chrome yellow, nickel titanium yellow, Chrome orange, molybdate red, iron oxide red, mineral violet, ultramarine violet, Ultramarine blue, cobalt blue, chrome oxide green, iron oxide black; colored organic Pigments such as toluidine red, lithol red, perylene red, thioindigo red, quinacridone red, Quinacridone violet, phthalocyanine blue, indanthrene blue, phthalocyanine green, carbon black, Graphite; Corrosion inhibitors such as zinc chromate, strontium chromate, zinc phosphate, Lead silicone chromate, barium etaborate and zinc borate.
• Effect pigments such as aluminum bronzes, pearlescent pigments or Interference pigments are used.
• Fillers Calcium carbonate, silicon dioxide, aluminum silicates, magnesium silicates, mica, Barium sulfate, aluminum hydroxide and silicas can be used.
• the aqueous pigmented component (B) can also be customary auxiliaries such as Anti-foaming agents, dispersing agents and rheology control agents added become.
• the aqueous pigmented component (B) is prepared in the usual manner, the Those skilled in the art by dispersing the pigments and auxiliaries in the Paste resin.
• the composition of the ingredients for optimal dispersion is determined separately for each dispersing unit.
• dispersing units are suitable, for example, stirring disc devices, three-roll mills, ball mills or preferably sand or pearl mills.
• Components (A) and (B) are combined in one for coating Mixing ratio of 1: 1 to 4: 1 based on the weight of each aqueous components used.
• both components can be used simultaneously or in succession in the bathroom be fed.
• the components are preferred with part of the Bath material premixed in a conventional mixing device.
• a mixing organ can, for example, a stirred tank, a static mixer or a rotor / stator mixer his.
• the components (A) and (B) can also be previously in the desired Are mixed and used as a one-component material for the ratio Post compensation can be used.
• component (A) is included additional neutralizing agent added to the desired MEQ value of Obtain ATL bath and if necessary prediluted with water. After that, in the above-described way, component (B) and the mixture on the desired final solid for the coating.
• Another Process variant is first the required amount of water with the Submit neutralizing agent and components (A) and (B) in the to supply as described above.
• the ATL bath has a solids content of 8 to 25% by weight during operation, preferably from 10 to 15% by weight an MEQ value from 50 to 90, preferably from 60 up to 70 and an organic solvent content of less than 0.3% by weight.
• the deposition is carried out by applying a DC voltage of 50 to 500 volts a coating time of 0.5 to 5 minutes at a temperature of the ATL bath from 18 to 35 ° C.
• the coating material is suitable for coating workpieces with an electrically conductive surface, in particular for priming and Single-coat painting of household and electrical appliances, steel furniture, components, construction and agricultural machinery, automobile bodies and automotive accessories.
• aqueous binder component (A1) 90.60 kg of the aqueous binder component (A1) are added in a dissolver mixer with stirring, 9.40 kg of a melamine resin of the hexamethylol melamine resin type and stirred at 40 ° C. for 30 minutes. Solid 30 minutes at 180 ° C 60.8% MEQ-amine 24.6 milliequivalents of amine / 100 g of solid
• Crosslinker-containing pigment-free aqueous binder component (A3)

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• Electrochemistry (AREA)
• Materials Engineering (AREA)
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• Paints Or Removers (AREA)
• Application Of Or Painting With Fluid Materials (AREA)
• Peptides Or Proteins (AREA)
• Saccharide Compounds (AREA)
• Apparatuses And Processes For Manufacturing Resistors (AREA)

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• 1998
  • 1998-01-17 DE DE19801605A patent/DE19801605C1/de not_active Expired - Fee Related
• 1999
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