Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D1/00—Processes for applying liquids or other fluent materials
  • B05D1/36—Successively applying liquids or other fluent materials, e.g. without intermediate treatment
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
  • B05D7/50—Multilayers
  • B05D7/56—Three layers or more
  • B05D7/57—Three layers or more the last layer being a clear coat
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
  • B05D7/50—Multilayers
  • B05D7/56—Three layers or more
  • B05D7/58—No clear coat specified
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/31504—Composite [nonstructural laminate]
  • Y10T428/31551—Of polyamidoester [polyurethane, polyisocyanate, polycarbamate, etc.]

Definitions

• the invention relates to a method for producing a multilayer coating, using cationic binders, in the manufacture of the cationic filler coating agent.
• Automobile painting is nowadays a multi-layer painting to meet the different requirements of consumers.
• the different layers of paint serve different purposes, for example to create stone chip protection, to create corrosion protection or to produce a good, visually appealing surface.
• the primer for the production of the corrosion protection can be produced from coating agents on an anionic or cationic basis.
• the filler layers that are necessary to produce sufficient stone chip protection are nowadays formulated either on a solvent-based basis or on an aqueous basis.
• aqueous systems that are formulated on an anionic basis are known.
• These coating agents have the disadvantage that if the corrosion primer layer is damaged, there is only poor corrosion protection at these points.
• the stoving temperatures of the filler layer are relatively high. For practical reasons, e.g. B. energy costs or dimensional stability of plastic substrates, it is necessary to keep the baking temperatures of the lacquer layers as low as possible.
• Binder on a cationic basis which are used for corrosion protection primers, have already been described in the patent literature. These are deposited by electrocoating, which means that there is an aqueous solution of the binders together with the usual ones Manufactured additives and deposited them by applying an electrical current to the metallic workpiece connected as a cathode. The coated substrate is then baked at temperatures between 150 and 200 ° C, which means that the coating chemically crosslinks. Examples of such coating compositions are described in DE-OS 36 34 483, 36 14 551, 36 14 435, EP-A 54 193 and EP-A 193 103.
• binders for paint that can be deposited on the cathode and are based on amino acrylate resins, amino epoxy resins or aminourethane resins. These are mixed and dispersed with pigments in a pigment-binder ratio of up to 0.5: 1 and the coating agent is produced with the usual paint additives.
• the solids content of the coating compositions is generally 12-22% by weight. After coating, these coating agents are baked at temperatures> 150 ° C.
• coating agents have the disadvantage that they have only a low solids content and are therefore unsuitable for spray application.
• baking it is first necessary to evaporate the water still present in the coating agent.
• high temperatures are required to crosslink the coating agent, so that the selection of the substrates that can be used is restricted.
• Coating agents for stone chip protection are also known. These so-called fillers are known for example from DE-OS 40 00 748, EP-A 249 727 or DE-OS 38 13 866. These are coating compositions based on anionically stabilized binders, which are processed with conventional pigments and additives to form the coating composition. Polyurethane resins and reaction products of polyesters and epoxy resins are described as the binder base. Melamine resins and blocked isocyanates are described as crosslinking agents. These coating agents have the disadvantage that they require relatively high baking temperatures of approx. 150 ° C. It has also been shown that the corrosion protection on bare metal spots that do not have a corrosion protection primer is not sufficient. Such defects can, for example, by necessary subsequent processing of the bodies, for. B. loops occur.
• This object is achieved according to the invention by the production of filler layers from coating compositions based on one or more binders which at least partially contain cationic groups or groups which can be converted into cationic groups.
• the filler layer can, for example, on a conventional primer, for. B. a cathodically or anodically or otherwise deposited primer layer can be applied directly.
• intermediate layers can also be formed between the primer and the filler layer, such as. B. rockfall protection layers.
• the filler layer is preferably overcoated with a customary color and / or effect topcoat or basecoat.
• one or more intermediate layers can also be inserted here.
• the filler layers produced according to the invention can be crosslinked or baked at low temperatures, e.g. B. at 100 to 150 ° C.
• the coating agents used for the filler layers can contain, in addition to the one or more cationically stabilized binders, further binders and crosslinking agents. You can also use conventional pigments and / or fillers, as well as conventional paint additives, such as. B. contain catalysts. They can contain water and / or organic solvents as solvents. They preferably contain water as the main solvent, with small proportions of one or more organic solvents. Water is preferably used in fully demineralized form.
• the binders are preferably based on polyacrylate, polyester, polyurethane or epoxy resins or mixtures thereof. At least some of them contain cationic groups or substituents which can be converted into cationic groups. These cationic groups can e.g. B. contain nitrogen and be quaternized. Convertible to cationic groups Groups can also contain nitrogen, for example, and by conventional neutralizing agents, e.g. B. neutralized inorganic acids or organic acids or converted into cationic groups. Examples of usable acids are phosphoric acid, acetic acid and formic acid. The solubility behavior in water is influenced by the number of these groups.
• the binders can be self- or externally crosslinking, ie crosslinking agents can also be added.
• Binders that can be added in part are also understood to mean resins that perform special paint technology functions. Examples of this are rheological resins or paste resins.
• binders which can be used according to the invention in the coating compositions for fillers are listed below. It can e.g. B. the binders are used, which are described in DE patent application P 40 11 633 for basecoats.
• B. basic group-containing poly (meth) acrylate resins which are prepared by solution polymerization or by emulsion polymerization or copolymerization and have a hydroxyl number of 10 to 400, preferably 30 to 200 mg KOH per g solid resin.
• the number average molecular weight ( M ⁇ n) is 500 to 100000 and preferably 1000 to 10000 (measured by gel permeation chromatography, calibrated with polystyrene fractions).
• Their viscosity is preferably 0.1 to 10 Pa.s, in particular 0.5 to 5 Pa.s in 50% solution in monoglycol ethers (in particular butoxyethanol) at 25 ° C.
• Their glass transition temperature (calculated from the glass transition temperatures of the homopolymers) is from -50 to + 150 ° C, preferably from -20 to + 75 ° C.
• the suitable average molecular weights or viscosities can also be obtained by mixing resins with higher and lower molecular weights or viscosities.
• the amine number is 20 to 200, preferably 30 to 150 and particularly preferably 45 to 100 (mg KOH per g solid resin).
• the basic group-containing poly (meth) acrylate resins can be prepared according to the prior art, as described, for example, in DE-A 15 46 854, DE-A 23 25 177 or DE-A 23 57 152. Practically all radically polymerizable monomers can be used ethylenically unsaturated monomers.
• the basic poly (meth) acrylate resin can also be used instead of or in addition to the amino groups Contain onium groups such as quaternary ammonium groups, sulfonium or phosphonium groups. Amino groups which make the resin dilutable with water after neutralization with organic acids are particularly preferred.
• Such a mixed polymer containing amino groups and hydroxyl groups is obtained by polymerization in solution or by emulsion polymerization. Solution polymerization is preferred.
• the poly (meth) acrylate resin is prepared from (meth) acrylate monomers, optionally together with other radically polymerizable monomers.
• the radically polymerizable monomers i.e. H. the (meth) acrylate monomers and / or further free-radically polymerizable monomers are free-radically polymerizable amino group-containing monomers or free-radically polymerizable monomers which contain both amino groups and hydroxyl groups. They can be used in a mixture with other radically polymerizable monomers.
• unsaturated N group-containing monomers are N-dialkyl or N-monoalkylaminoalkyl (meth) acrylates or the corresponding N-alkanol compounds or the corresponding (meth) acrylamide derivatives.
• Radically polymerizable monomers containing hydroxyl groups are understood to mean, for example, those which, in addition to a polymerizable ethylenically unsaturated group, also contain at least one hydroxyl group on a C2 to C20 linear, branched or cyclic carbon skeleton.
• the copolymerization is carried out in a known manner, preferably by solution polymerization with the addition of free radical initiators and optionally regulators at temperatures of, for. B. 50 to 160 ° C. It takes place in a liquid in which monomers and polymers dissolve together. The content of monomers or polymers after the polymerization is about 50 to 90% by weight.
• Solution polymerization in organic solvents that are dilutable with water is preferred.
• initiators which are soluble in organic solvents 0.1 to 5% by weight, preferably 0.5 to 3% by weight, based on the amount of monomers used, of peroxides and / or azo compounds are added.
• initiators such. B. peroxides, peresters or azo compounds which decompose thermally into radicals.
• the molecular weight can be reduced in a known manner by using regulators.
• Mercaptans, halogen-containing compounds and other radical-transferring substances are preferably used for this purpose.
• Particularly preferred are n- or tert-dodecyl mercaptan, tetrakismercaptoacetylpentaerythritol, tert-butyl-o-thiocresol, buten-1-ol or dimeric ⁇ -methylstyrene.
• Amino-poly (meth) acrylate resins can also be prepared by polymer-analogous reaction.
• a copolymer containing acrylamide groups can be reacted with formaldehyde and a secondary amine and / or amino alcohol.
• a particularly preferred method is described in DE-A 34 36 346.
• epoxy group-containing monoethylenically unsaturated monomers are first polymerized into the copolymer. It is then reacted with excess ammonia, primary and / or secondary monoamines and / or monoamino alcohols and then the excess of amine is distilled off.
• a similar reaction can preferably be carried out, for example, in equivalent amounts with ketimines or polyamines which contain a secondary amino group and one or more blocked or tertiary amino groups, such as the monoketimine from methyl isobutyl ketone and methylaminopropylamine or the diketimine from methyl isobutyl ketone and diethylene triamine.
• the proportion of unsaturated monomers containing epoxy groups in the copolymer is generally 8 to 50% by weight.
• the lower limit is preferably 12% by weight, the upper limit 35% by weight.
• the polymerization must be completed before the reaction with amines takes place. because otherwise reversible side reactions occur on the activated double bonds of the monomers with the secondary amines.
• the following amines can be used for the reaction, for example: C1 to C6 dialkylamines with the same or different alkyl groups in the molecule, monocycloaliphatic amines, monoalkanolamines, dialkanolamines and primary amines or amino alcohols.
• Secondary amines such as dimethylamine, diethylamine, methylethylamine or N-methylaminoethanol are particularly preferred because, after neutralization, readily soluble paints with a high pH can be obtained.
• the primary amines mentioned above are mostly used in a mixture with secondary amines, because otherwise highly viscous products are formed.
• the number of epoxy groups determines the number of amino groups that are reacted with them and thus also the solubility of the product. There should be at least one epoxy group per molecule. It is often advantageous to combine an increased hydroxyl number with a low amine number and vice versa.
• the development goal is generally a highly soluble product with a low degree of neutralization and the highest possible
• amino groups can be incorporated by reacting a hydroxyl-containing poly (meth) acrylate resin with amino compounds containing isocyanate groups. These are produced, for example, by reacting 1 mol of diisocyanate with 1 mol of dialkylaminoalkanol.
• Another preferred group of basic binders are hydroxyl-functional polyesters, the amino groups as amino alcohols either being condensed directly into the polyester or being incorporated more gently into the polymer chain with the aid of a polyaddition or being attached to the polymer chain.
• an OH group-containing urethanized polyester is built up by reacting a polyester with dialkylaminodialcohols and diisocyanates. It is also possible to use fractions of higher functional alcohols, amino alcohols or isocyanates. If you work with an isocyanate deficit, the resin must be directly dispersible in water after neutralization with acids.
• the resulting NCO prepolymer can be dispersed in water and converted into a polyurethane (urea) dispersion by chain extension with a polyamine.
• urea polyurethane
• These binders do not contain any groups accessible to crosslinking. They can therefore only be used in part.
• the equivalent ratio of the diisocyanate used is chosen in coordination with the polyols and diols used so that the finished polyester urethane resin preferably has a number average molecular weight ( M ⁇ n) from 3,000 to 200,000, particularly preferably below 50,000.
• the viscosity of the polyester urethane resin is preferably 1 to 30 Pa.s., particularly preferably above 5 and below 15 Pa.s, measured 60% in butoxyethanol at 25 ° C.
• polyurethane (urea) dispersions containing basic groups is carried out in a known manner, for. B. by chain extension of a cationic or cationizable prepolymer having a terminal isocyanate group with water, polyols, polyamines and / or hydrazine compounds, the chain extension taking place before or after neutralization of the tertiary amino groups with these in water.
• the amine number is controlled by the amount of compounds containing cation groups in the prepolymer containing isocyanate groups used in the preparation.
• the particle size depends on the molar mass of the used polyols, e.g. B. OH polyester (polyester polyols), the amine number and the assembly sequence.
• the number average molecular weight is preferably between 3000 to 500000, particularly preferably more than 5000 and less than 50000.
• Polyurethane dispersions containing urea groups are preferably prepared which contain at least 2, preferably 4 urethane groups and at least one tertiary amino group, especially dialkylamine group in the NCO prepolymer contain.
• the preparation of the cationic isocyanate group-containing prepolymers suitable for use in polyurethane (urea) dispersions is carried out, for. B. by simultaneous reaction of a polyol mixture with diisocyanates in a preferred ratio of NCO to OH groups of over 1.00 to 1.4.
• the polyol mixture preferably consists of one or more saturated OH polyesters, optionally with the addition of one or more low molecular weight diols and a compound with two groups which are H-reactive toward isocyanate groups and which additionally contain a group capable of forming cations.
• the polyester polyol can be prepared in various ways, for example in the melt or by azeotropic condensation at temperatures of, for. B. 160 to 260 ° C, preferably from dicarboxylic acids and dialcohols, which may optionally be slightly modified by small amounts of trial alcohols.
• the reaction is carried out, optionally with the addition of catalysts such as tin octoate or dibutyltin oxide, until practically all of the carboxyl groups (acid number ⁇ 1) have been reacted.
• the necessary OH number from 35 to 200, preferably above 50 and below 150, or molar mass from 500 to 5000, preferably above 800 and below 3000, is determined by the alcohol excess used.
• the preferred dicarboxylic acids are linear or branched aliphatic, alicyclic or aromatic.
• diols with sterically hindered primary OH groups or with secondary hydroxyl groups are used. Examples include 1,4-cyclohexanediol, 2-ethyl-1,3-hexanediol, cyclohexanedimethanol and the hydrogenated bisphenols A or F.
• the dialcohols can contain small amounts of higher polyols, such as glycerol or trimethylolpropane, for branching introduce. However, the amount should be so small that no cross-linked products are created.
• a linear aliphatic structure is preferred, which may optionally contain an aromatic dicarboxylic acid in part and preferably contains an OH group at the end of the molecule.
• polyester diols obtained by condensation of hydroxycarboxylic acids can also be used as polyester polyols.
• 2 to 30% by weight of the higher molecular weight polyester can be exchanged for low molecular weight glycols or dialcanols.
• the dialcanols already used in the polyester with a molecular weight of 62 to about 350 are preferably used for this.
• the dialcanols used do not have to be identical to those used in the polyester.
• diols which still contain at least one onium salt group or an amino group which can be neutralized by acid.
• Suitable basic groups which are capable of forming cations are primary, secondary or tertiary amino groups and / or onium groups, such as quaternary amino groups, quaternary phosphonium groups and / or tertiary sulfonium groups.
• Dialkylamino groups are preferably used. The basic groups should be so inert that the isocyanate groups of the diisocyanate preferably react with the hydroxyl groups of the molecule.
• aliphatic diols such as N-alkyl-dialkanolamines, with, as alkyl or alkane radical, aliphatic or / cycloaliphatic radicals with 1 to 10 carbon atoms, e.g. B. methyl diethanolamine.
• the amount of salt groups present as a result of the neutralization is generally at least 0.4% by weight to about 6% by weight, based on the solids.
• the cationic groups of the NCO prepolymer used for the production of the polyurethane dispersions are mixed with a Acid at least partially neutralized.
• the resulting increase in dispersibility in water is sufficient to stably disperse the neutralized polyurethane containing urea groups.
• Suitable acids are organic monocarboxylic acids.
• the NCO prepolymer is diluted with water and then gives a finely divided dispersion with an average particle diameter of 25 to 500 nm.
• the isocyanate groups still present can be treated with di- and / or polyamines with primary and / or secondary amino groups, or Hydrazine and its derivatives or dihydrazides can be implemented as chain extenders.
• the amount of chain extender is determined by its functionality or by the NCO content of the prepolymer.
• the ratio of the reactive amino group in the chain extender to the NCO groups in the prepolymer should generally be less than 1: 1 and preferably in the range from 1: 1 to 0.75: 1.
• Examples are polyamines with a linear or branched aliphatic, cycloaliphatic and / or (alkyl) aromatic structure and at least two primary amino groups.
• Examples of diamines are ethylenediamine, 1,6-hexamethylenediamine, isophoronediamine and aminoethylethanolamine.
• Preferred diamines are ethylenediamine, propylenediamine and 1-amino-3-aminomethyl-3.3.5-trimethylcyclohexane or mixtures thereof.
• the chain extension can be carried out at least in part with a polyamine which has at least three amino groups with reactive hydrogen, such as, for example, diethylene triamine.
• Diamines can also be used as chain extenders, the primary amino groups of which are protected as ketimine and which become reactive after emulsification in water due to the hydrolytic cleavage of the ketone.
• the polyaddition is carried out with strong dilution using dry, non-isocyanate-reactive solvents.
• the chain is extended with polyols, polyamines or amino alcohols.
• Low-boiling water-free ketones such as acetone, methyl ethyl ketone or methyl isopropyl ketone, but also esters such as acetoacetic ester are used as solvents.
• the volatile solvent may then have to be distilled off under heating with heating.
• Typical diisocyanates for reaction with the polyol / diol mixture are, for example, those based on linear or branched aliphatic, cycloaliphatic and / or aromatic hydrocarbons with an NCO content of 20 to 50%. They contain two isocyanate groups as functional groups, which are arranged asymmetrically or symmetrically in the molecule. They can be aliphatic, alicyclic, arylaliphatic or aromatic.
• the synthesis is carried out by joint reaction of the reactants in a mixture or stepwise to a sequential structure.
• Polyisocyanates with more than 2 isocyanate groups are defunctionalized by reaction with isocyanate-reactive monofunctional compounds. Preference is given to compounds which retain a basic amino group after the reaction in order to introduce a salt-forming group in this way.
• dialkylaminoalkanols or dialkylaminoalkylamines basic "diisocyanates" are prepared under gentle reaction conditions, the alkyl groups being linear or branched, aliphatic or cycloaliphatic with carbon chains of 1 to 10 carbon atoms.
• binders contain essentially no groups accessible to crosslinking. They can therefore only be used partially in the coating agent.
• Binding agents based on cationic polyepoxy resins have already been described in the literature.
• DE-OS 38 12 251, EP-A 0 234 395, DE-OS 27 01 002, EP-A 0 287 091, EP-A 0 082 291 or EP-A 0 227 975 describe self- or externally crosslinking binders described on the basis of reaction products of polyepoxides with compounds containing amine groups. These are, for example, reaction products of polyepoxides with aromatic or aliphatic diols and / or diamines. These reaction products can be further modified, e.g. B.
• aromatic components e.g. B. aromatic diols such as bisphenol A, improve the corrosion protection behavior, cause aliphatic components, for. B. aliphatic glycol ethers such as polyethylene glycols, increased flexibility of the binder.
• the solubility can be influenced by the number of amino groups.
• the amine number should be between 20 and 200 mg KOH / g solid resin, preferably between 30 and 150.
• Primary, secondary and / or tertiary amino groups can be present.
• the hydroxyl number influences the crosslink density. It should preferably be between 20 and 400.
• Each binder molecule should have an average of at least two reactive groups, e.g. B. OH or NH groups.
• the reactivity of the binders will influenced by the nature of the groups, primary amino or hydroxyl groups are more reactive than secondary ones, with NH groups being more reactive than OH groups. It is preferred that the binders contain reactive amino groups.
• the binders according to the invention can carry other crosslinkable groups, such as. B.
• the molecular weight ( M ⁇ n) the binder is from 500 to 20,000, in particular from 1,000 to 10,000.
• the basic resin binders described are self-crosslinking or externally crosslinking and can be used either individually or in a mixture.
• Crosslinking agents can also be mixed in to achieve a crosslinked filler layer.
• the amount can be selected according to the respective functionality. It is z. B. 0 - 40 wt .-%, based on the mixture of binders and crosslinkers.
• aminoplast resins such as. B. melamine resins
• crosslinkers for example, aminoplast resins, such as. B. melamine resins can be used.
• they can also be modified, e.g. B. by etherification with unsaturated alcohols. These substances are common commercial products.
• transesterification crosslinkers are non-acidic polyesters with side or terminal ⁇ -hydroxyalkyl ester groups. They are esters of aromatic polycarboxylic acids, such as isophthalic acid, terephthalic acid, trimellitic acid or mixtures thereof. These are e.g. B. condensed with ethylene glycol, neopentyl glycol, trimethylolpropane and / or pentaerythritol. The carboxyl groups are then reacted with optionally substituted 1,2-glycols to form ⁇ -hydroxyalkyl compounds. The 1,2-glycols can be substituted with saturated or unsaturated alkyl, ether, ester or amide groups. Furthermore, a hydroxyalkyl ester formation is also possible in which the carboxyl groups with substituted glycidyl compounds, such as. B. glycidyl ethers and glycidyl esters are implemented.
• the product preferably contains more than 3 ⁇ -hydroxyalkyl ester groups per molecule and has a weight average molecular weight of 1,000 to 10,000, preferably 1,500 to 5,000.
• the usable non-acidic polyesters with side or terminal ⁇ -hydroxyalkyl ester groups can be prepared, for example in EP -A 0 012 463.
• the compounds described there are also examples of polyesters that can be used.
• the di- and polyisocyanates described earlier can also be used as crosslinkers, the reactive isocyanate groups being blocked by protective groups.
• the so-called "lacquer polyisocyanates” which are prepared from the aliphatic diisocyanates already described above are particularly suitable as polyisocyanates.
• Another group of polyfunctional isocyanates are oxadiazinetrione alkyl diisocyanates, which can be added to trimethylolpropane.
• Highly functional polyisocyanates can also be prepared by reacting 2 moles of triisocyanates with H-active difunctional compounds, such as dialcohols, diamines or amino alcohols, such as ethanolamines.
• the free isocyanate groups are blocked (blocked) together or individually, so that they are protected at room temperature against water or the active hydrogen atoms of the base resin (hydroxyl or amine-hydrogen groups).
• Suitable blocking agents are monofunctional, acidic hydrogen-containing compounds with only a single amine, amide, imide, lactam, thio, ketoxime or hydroxyl group. The products obtained in this way have been widely described in the literature.
• Organic pigments iron oxides, lead oxides, titanium dioxide, barium sulfate, zinc oxide, mica, kaolin, quartz powder or various types of silica are possible as pigments or fillers.
• the particle diameter of the pigments should be ⁇ 15 ⁇ m. It is also possible to at least partially crosslinked organic fillers to be used insofar as these do not swell in the solvent and have the required grain size.
• lacquer additives examples include rheology-influencing agents, anti-settling agents, leveling agents, anti-foaming agents, dispersing aids and catalysts. These are used for the special setting of paint or application properties.
• solvents are suitable as solvents. These can result from the production of the binders. It is advantageous if the solvents are at least partially miscible with water.
• examples of such solvents are glycol ethers, e.g. B. butyl glycol, ethoxypropanol, diethylene glycol dimethyl ether; Alcohols, e.g. B. isopropanol, n-butanol; Glycols, e.g. B. ethylene glycol; N-methylpyrrolidone and ketones.
• the course and the viscosity of the coating agent can be influenced by the choice of the solvent.
• the evaporation behavior can be influenced via the boiling point of the solvents used.
• the pigment-binder weight ratio is, for example, between 0.75: 1 to 2.5: 1, preferably 1.0: 1 to 1.8: 1.
• the solids content of the coating composition is between 25 and 60% by weight, preferably between 30 and 50% by weight.
• the solvent content is ⁇ 15% by weight, preferably ⁇ 10% by weight, based in each case on the aqueous coating agent.
• the starting material is the aqueous binder dispersion, into which pigments, fillers and additives and auxiliaries are added with thorough stirring. After thorough homogenization, the mixture is optionally ground to the necessary fineness. Suitable grinding units have already been described in the literature. After the coating agent has been ground, other binders, if appropriate also different ones, can be added. A suitable viscosity can then be adjusted using water or organic solvent. As a further procedure, it is e.g. B. possible to disperse the pigments and auxiliaries in a solvent-containing binder form, optionally grinding and the mixture after neutralization in the To transfer water phase. Then the viscosity can be adjusted with water. The finished coating agent can be stored for a long time and shows no significant changes in viscosity or sedimentation tendency. For application, a suitable low viscosity, for. B. can be set for spraying.
• the coating agent is applied by rolling, rolling or spraying, preferably using spray application processes. Examples of this are compressed air spraying, airless spraying, hot spraying or electrostatic spraying. Automotive bodies or parts thereof are particularly suitable as substrates; they can be made of metal or plastic. Metal parts are usually coated with an electrophoretically deposited anti-corrosion primer or another common primer layer or intermediate layer. This is usually baked at temperatures> 150 ° C. Examples of such primers are described in DE-A 36 15 810, DE-A 36 28 121, DE-A 3823 731, DE-A 39 20 214, DE-A 39 40 782 and EP-A 0 082 291, EP- A 0 209 857 and EP-A 234 395. Plastic substrates are provided with adhesion-improving coating layers or with primers based on 2-component coating agents or physically drying coating agents. These coatings can optionally by mechanical work, for. B. loops to be treated.
• the coating agent according to the invention is applied to the precoated substrates. After a short flash-off time, if necessary at elevated temperatures, the workpiece with the coating layer is baked at temperatures between 100 and 150 ° C. The layer thickness is 15-120 ⁇ m, preferably between 25 and 80 ⁇ m. After crosslinking, the surface is optionally post-treated, e.g. B. by grinding to create a smooth surface without defects. Thereafter, the color and / or effect paint layer, z. B. a uni top coat or a metallic basecoat can be applied. When using aqueous anionic basecoat layers, particularly good adhesion to the filler layer can be achieved.
• the process according to the invention is particularly suitable for producing a multi-layer coating. This also shows improved corrosion protection on metal parts in the event of mechanical injuries.
• optically smooth, homogeneous, stone chip resistant multi-layer coatings are provided. These meet the increased requirements in serial painting in the automotive industry.
• a solution of 2878 g of an epoxy resin based on bisphenol A with an epoxy equivalent weight of 194 and 1497 g nonylphenol in 1093 g xylene was prepared and heated to 100 ° C. 2 g of a 50% aqueous solution of tetrabutylammonium chloride were added to this solution and, after heating to 140.degree. C., held until the epoxy equivalent weight of the solution was 740. After cooling to 50 ° C, a solution of 1225 g of ethylenediamine in 1225 g of xylene was added. After 4 hours at 105 ° C, excess xylene / diamine mixture was distilled off in vacuo.
• This mixture was then ground intensively in a bead mill and mixed with 5.92 parts of the binder from Example 3, 0.21 parts of a commercially available nonionic surfactant, 5.93 parts of the crosslinking agent from Example 4, 24.17 parts of deionized water and 0.17 Parts of a 50% aqueous solution of formic acid varnished.
• This gray cationic hydraulic filler was sprayed onto a test sheet coated with KTL (18 ⁇ m) in a dry layer thickness of 30 to 35 ⁇ m and baked in the gradient oven at 130 to 190 ° C for 20 minutes.
• the test sheet was partially masked after baking and then coated with a commercially available single-layer top coat in a dry layer thickness of 40 ⁇ m by spray application and baked at 130 ° C.
• the corrosion protection of the substrates coated according to the invention is also good if the KTL primer has defects up to the metal.

Landscapes

• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Wood Science & Technology (AREA)
• Paints Or Removers (AREA)
• Application Of Or Painting With Fluid Materials (AREA)

Applications Claiming Priority (2)

Publications (2)

Family

ID=6442838

Family Applications (1)

Country Status (8)

Families Citing this family (9)

Citations (2)

Family Cites Families (24)

• 1991
  • 1991-10-17 DE DE4134301A patent/DE4134301A1/de not_active Withdrawn
• 1992
  • 1992-10-13 CA CA002080410A patent/CA2080410A1/fr not_active Abandoned
  • 1992-10-14 EP EP92117510A patent/EP0537697B1/fr not_active Expired - Lifetime
  • 1992-10-14 DE DE59203561T patent/DE59203561D1/de not_active Expired - Fee Related
  • 1992-10-16 AU AU27126/92A patent/AU659686B2/en not_active Ceased
  • 1992-10-16 TW TW081108235A patent/TW211579B/zh active
  • 1992-10-16 KR KR1019920019072A patent/KR930007521A/ko not_active Application Discontinuation
  • 1992-10-19 JP JP4280188A patent/JPH05208168A/ja active Pending
• 1995
  • 1995-03-06 US US08/400,297 patent/US5552227A/en not_active Expired - Fee Related

Patent Citations (2)

Also Published As

Similar Documents

Legal Events