Classifications

• • 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
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/08—Processes
• • 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
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/08—Processes
  • C08G18/10—Prepolymer processes involving reaction of isocyanates or isothiocyanates with compounds having active hydrogen in a first reaction step
  • C08G18/12—Prepolymer processes involving reaction of isocyanates or isothiocyanates with compounds having active hydrogen in a first reaction step using two or more compounds having active hydrogen in the first polymerisation step
• • 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
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/08—Processes
  • C08G18/0804—Manufacture of polymers containing ionic or ionogenic groups
  • C08G18/0819—Manufacture of polymers containing ionic or ionogenic groups containing anionic or anionogenic groups
  • C08G18/0823—Manufacture of polymers containing ionic or ionogenic groups containing anionic or anionogenic groups containing carboxylate salt groups or groups forming them
• • 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
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
  • C08G18/40—High-molecular-weight compounds
  • C08G18/42—Polycondensates having carboxylic or carbonic ester groups in the main chain
  • C08G18/44—Polycarbonates
• • 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
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
  • C08G18/65—Low-molecular-weight compounds having active hydrogen with high-molecular-weight compounds having active hydrogen
  • C08G18/66—Compounds of groups C08G18/42, C08G18/48, or C08G18/52
  • C08G18/6633—Compounds of group C08G18/42
  • C08G18/6659—Compounds of group C08G18/42 with compounds of group C08G18/34
• • 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
  • C09D175/00—Coating compositions based on polyureas or polyurethanes; Coating compositions based on derivatives of such polymers
  • C09D175/04—Polyurethanes
  • C09D175/06—Polyurethanes from polyesters

Definitions

• the invention relates to new polyurethane dispersions, a process for their preparation and their use in aqueous binders for fast-drying coatings in automotive painting.
• a multi-layer structure has established itself in automotive serial painting, which is increasingly being achieved with aqueous coating agents. Due to the special properties of the dispersant or solvent water, aqueous coatings often have the problem that drying has to take place at relatively high temperatures and / or for relatively long times in order to achieve optimum coating properties. However, modern coatings increasingly have to meet requirements for high cost-effectiveness.
• One of the main goals is, for example, to apply the coating structure in the automotive painting process in as few and as inexpensive as possible, that is to say, in particular, quickly successive individual steps. High drying temperatures, long flash-off times or long drying times stand in the way of this requirement.
• a stone chip protection layer and a filler layer or a combination of both ('stone chip protection filler') is first applied to a metal surface primed by cathodic electrocoating (KTL).
• KTL cathodic electrocoating
• a pigmented basecoat, then a clearcoat or alternatively a pigmented topcoat is then applied to these layers.
• the stone chip protection filler layer compensates for unevenness in the surface and, due to its high elasticity and deformability, provides good resistance to stone chips. So far, therefore, polyesters and polyurethanes as well as polyisocyanate or melamine crosslinkers have been used for this layer.
• the stone chip protection filler is baked before application of the basecoat and clearcoat or topcoat. This is necessary to improve the topcoat level and possibly to close any remaining imperfections in the filler layer. After the clearcoat or topcoat has been applied, it is then baked again.
• the disadvantage of this method is that two complex baking processes are necessary. Physically, ie without a baking process, quick-drying lacquers, such as those that can be formulated from polyacrylates, do not have the required stone chip resistance, since they lead to films with insufficient film-mechanical properties when hardened.
• the object of the present invention was to provide a binder for a barrier layer with stone chip protection function which, in addition to good stone chip resistance, above all ensures very rapid physical drying and the coating obtained after the rapid physical drying has very good water resistance and against dissolving the subsequently applied basecoat or topcoat is resistant.
• the adhesion or interlayer adhesion must be excellent in order to achieve an optimal
• the binder must be lightfast in order to produce a weather-resistant coating even in the case of moderately opaque topcoats or basecoats or in places where there is no pigmented topcoat or basecoat at all.
• Excellent stability is also required, in particular viscosity stability in the form of appropriately formulated paints and practical repairability for necessary repairs directly on the line.
• a proposed solution for stone chip resistant coatings and / or filler layers based on aqueous binders is e.g. B. described in EP-A-0 330 139.
• the stressed dispersions of acid-functional polyesters are only stable in storage to a limited extent, since they are subject to rapid chemical degradation by cleavage of ester bonds (eg Jones, TE; McCarthy, JM, J. Coatings Technol. 76 (844), p. 57 (1995)).
• EP-A-0 498 156 describes polyester dispersions containing urethane groups, which are very good for the production of stone chip protection intermediate primer. en or of stoving fillers with high stone chip resistance. In order to achieve this high level of properties, however, high curing temperatures or long curing times are required.
• DE-A-3 936 794 describes polyurethane dispersions containing carbonate groups and their use in automotive coating, e.g. for basecoats, both under baking conditions at approx. 140 ° C, and in the case of repairs on the line at approx. 80 ° C. Important requirements that these dispersions must meet are e.g. Adhesion, weather resistance and condensation resistance even at 80 ° C drying.
• DE-A-4 438 504 describes lacquer layer formulations based on water-thinnable polyurethane resins having an average molecular weight Mn of 4000 to 25000 g / mol, with which lacquer films for filler and stone chip intermediate layers can be produced which are as thin as possible.
• the invention thus relates to aqueous polyurethane dispersions from reaction products of
• the invention also relates to a process for the preparation of the polyurethane dispersions according to the invention, characterized in that an NCO- and acid-functional polyurethane prepolymer is first prepared from the components A), B), C) and D) mentioned in organic solution, and then for at least 40, but at most 105% of the acid groups, neutralizing agent is added and the prepolymer thus obtained is dispersed in or with water, then if appropriate
• Neutralizing agent is added up to the maximum amount of the degree of neutralization of 105% and the mixture is stirred at 25 to 75 ° C. until the chain extension taking place under an NCO / water reaction is complete, during or after the dispersion or during or after the chain extension reaction. on the organic solvent is removed to an amount ⁇ 5%.
• the preferred procedure is to add neutralizing agent to the above-mentioned components A), B) and D) for at least 40, but at most 105% of the acid groups, and then with component C) in organic solution, an NCO- and acid-functional polyurethane prepolymer is prepared and the prepolymer obtained in this way is dispersed in or with water, then optionally neutralizing agent is added to the maximum amount of the degree of neutralization of 105% and the mixture is stirred at 25 to 75 ° C. until the chain extension taking place under an NCO-water reaction is completed is, during or after the dispersion or during or after the chain extension reaction, the organic solvent is removed to an amount ⁇ 5%.
• the invention also relates to the use of the polyurethane dispersions according to the invention in paints and coatings.
• Suitable components A) are at least difunctional polyesters, polyethers,
• Polyether polyamines, polycarbonates, polyester amides of the molecular range 500-6000 can be dihydroxy polyesters from dicarboxylic acids or their anhydrides, e.g. Adipic acid, succinic acid, phthalic anhydride, isophthalic acid, terephthalic acid, suberic acid, azelaic acid, sebaceic acid, tetrahydrophthalic acid, maleic anhydride, dimer fatty acids and diols, e.g. B.
• dicarboxylic acids or their anhydrides e.g. Adipic acid, succinic acid, phthalic anhydride, isophthalic acid, terephthalic acid, suberic acid, azelaic acid, sebaceic acid, tetrahydrophthalic acid, maleic anhydride, dimer fatty acids and diols, e.g. B.
• Polyesters can also be used which contain certain quantities of mono-, tri- or tetrafunctional raw materials, e.g.
• 2-ethyl-hexanoic acid Contain 2-ethyl-hexanoic acid, benzoic acid, soybean oil fatty acid, oleic acid, stearic fatty acid, sunflower oil fatty acid, trimellitic anhydride, trimethylolpropane, glycerol, pentaerythritol.
• Lactone-based polyesters in particular ⁇ -caprolactone
• polycarbonates such as are obtainable by reacting, for example, the above-mentioned diols with diaryl or dialkyl carbonates or phosgene, and castor oil can also be used.
• polyethers e.g. can be obtained using diols, triols, water or amines as the starter molecule by polymerizing propylene oxide and / or tetrahydrofuran, optionally with the use of small amounts of ethylene oxide and / or styrene oxide.
• Components A) which are preferably used are difunctional polyesters of molecular weight 840 to 2600 based on aliphatic raw materials such as e.g. Adipic acid, maleic anhydride, hexanediol, neopentyl glycol, ethylene glycol, propylene glycol, diethylene glycol, in particular aliphatic polyester diols of molecular weight
• Components A) preferably used are also aliphatic polycarbonate diols or polyester carbonate diols with a molecular weight of 840 to 2600.
• polyester diols are used alone, the selection of special polyester diols is important for good water resistance and hydrolysis stability, e.g. based on adipic acid, hexanediol, neopentyl glycol in the molecular weight range 1700 to 2100 advantageous.
• polycarbonate diols can lead to problems in film optics e.g. due to non-optimal course and under unfavorable circumstances also lead to non-optimal interlayer adhesion, which then requires the preparation of special recipes.
• Suitable low molecular weight components B) can be e.g. B. ethylene glycol, 1,4-butanediol, 1, 6-hexanediol, neopentyl glycol, trimethylolpropane, glycerol, pentaerythritol, trimethylpentanediol, propylene glycol, 1,3-propanediol, 1,4-cyclohexadi-methanol, or their reaction products with ethylene - and / or propylene oxide.
• the molecular weight of B) can be between 62 and 400.
• a trifunctional or higher-functional low-molecular alcohol such as trimethylolpropane, glycerol, pentaerythritol, or their reaction products with 1 to 6 mol of ethylene and / or propylene oxide is preferably used as component B).
• trifunctional alcohols such as trimethylolpropane or glycerol in a quantity of 0.5 to 4.0, preferably of 1.0 to 3.0% by weight is very particularly preferred.
• Suitable components C) can be di- and / or trifunctional aliphatic
• Isocyanates such as B. hexamethylene diisocyanate, butane diisocyanate, isophorone diisocyanate, l-methyl-2,4 (2,6) -diisocyanatocyclohexane, norbornane diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, hexahydroxylylene diisocyanate, nonane triisocyanate diisocyanate, 4,4'-diisocyanate.
• aromatic isocyanates such as e.g. 2,4 (2,6) -diisocyanatotoluene or 4,4'-
• 4,4'-diisocyanatodicyclohexylmethane and / or isophorone diisocyanate and / or hexamethylene diisocyanate and / or l-methyl-2,4 (2,6) -diisocyanatocyclohexane are preferably used.
• isophorone diisocyanate and / or hexamethylene diisocyanate or of mixtures of 4,4 "-diisocyanatodicyclohexylmethane with isophorone diisocyanate or hexamethylene diisocyanate is very particularly preferred.
• the very particularly preferred components C) enable the production of particularly high-quality polyurethane dispersions for barrier layers with an excellent level of stone chip protection and an overall convincing level of properties.
• Component D) consists of at least one (potentially) ionic compound with at least one acid group and at least one hydroxyl and / or amino group which is reactive towards isocyanate groups. These compounds are preferably at least one, preferably one or two hydroxyl and / or amino carboxylic acids. Suitable acids of this type are, for example, 2,2-bis (hydroxymethyl) alkane carboxylic acid such as dimethylol acetic acid, 2,2-dimethylol propionic acid, 2,2-dimethyl butyric acid or 2,2-dimethylol pentanoic acid, dihydroxysuccinic acid, hydroxypivalic acid or mixtures thereof Acids.
• 2,2-bis (hydroxymethyl) alkane carboxylic acid such as dimethylol acetic acid, 2,2-dimethylol propionic acid, 2,2-dimethyl butyric acid or 2,2-dimethylol pentanoic acid, dihydroxysuccinic acid, hydroxypivalic acid or mixtures thereof Acids.
• Dimethylolpropionic acid and / or hydroxypivalic acid is preferably used as component D).
• sulfonic acid diols of the type described in US Pat. No. 4,108,814, optionally containing ether groups, as anionic structural component D).
• the free acid groups represent the "potentially ionic" groups mentioned above, while the salt-like groups, in particular carboxylate groups, obtained by neutralization with neutralizing agents are "ionic" groups.
• Component D) is used in amounts such that the acid number is based on
• Solids content of the dispersion is ⁇ 25, preferably ⁇ 20 mg / KOH g substance.
• component E) can optionally also be used to a lesser extent in amounts ⁇ 4% by weight in the production of the polyurethane dispersions.
• Components E) cannot be ionic-hydrophilic polyethers which have one or two groups which are reactive toward isocyanate groups, in particular hydroxyl groups, and preferably have a molecular weight Mn of 350 to 2500 per molecule.
• aqueous polyurethane dispersions according to the invention preferably contain
• Particularly preferred aqueous polyurethane dispersions according to the invention contain reaction products A) 55 to 75% by weight of a mixture of 20 to 80% by weight of an aliphatic polyester diol with a molecular weight of 840 to 2100 and from 80 to 20% by weight of an aliphatic polycarbonate diol or polyester carbonate diol with a molecular weight of 1000 to 2100, B) 1 to 3 wt .-% of a trifunctional, low molecular weight alcohol, in particular
• Trimethylolpropane or glycerol C) 20 to 35% by weight isophorone diisocyanate and / or hexamethylene diisocyanate and / or a mixture of 4,4'-diisocyanatodicyclohexylmethane with isophorone diisocyanate or hexamethylene diisocyanate, D) 3.5 to 4.9% by weight dimethylolpropionic acid.
• reaction of the hydroxy-functional components A), B), D) and optionally E) with the isocyanate-functional component C) is carried out in a manner known per se in one or more stages, the quantitative ratios of the reactants being chosen so that the Equivalent ratio of NCO.OH groups at 2.5: 1 to
• the reaction can be carried out with the addition of small amounts of catalysts such as e.g. Dibutyltin dilaurate, tin 2-octoate, dibutyltin oxide or diazabicyclononane can be carried out.
• catalysts such as e.g. Dibutyltin dilaurate, tin 2-octoate, dibutyltin oxide or diazabicyclononane can be carried out.
• the reaction is carried out in 35 to 97% organic solution, particularly preferably in 55 to 75% acetone solution.
• neutralizing agent it is also possible to add the neutralizing agent to the dispersing water.
• Preferred neutralizing agents are e.g. B. triethylamine, N-methylmorpholine, dimethylisopropylamine, ethyldiisopropylamine, may also be suitable, for example diisopropylaminoethanol, dimethylethanolamine, dimethylisopropanolamine. Mixtures of different neutralizing agents can also be used. Ammonia is also suitable as a neutralizing agent in some cases.
• Ethyldiisopropylamine optionally in a mixture with other amines, is particularly preferred.
• the mixture is stirred until all the NCO groups have reacted by means of an NCO-water reaction with chain extension via isolated urea structural units. If necessary, further neutralizing agent can be added, the degree of neutralization based on acid groups incorporated being at most 105%.
• Dispersions according to the invention preferably contain less than 5% by weight, particularly preferably practically no organic solvent.
• the distillation is carried out in such a way that no neutralizing agent used is also distilled off. Should this be the case due to unfavorably chosen distillation conditions, the appropriate amount of neutralizing agent is then added to the dispersion again.
• chain extension of the NCO-functional polyurethane prepolymer in water mono-, di- or trifunctional chain extenders or chain terminators of the known type which optionally also contain ionic groups, acid groups or hydroxyl groups can optionally be used for up to 40% of the NCO groups present can be added. However, preferably only a chain extension is carried out via the NCO-water reaction.
• the dispersions according to the invention have a (calculated and based on 100% solids content) content of isolated urea structural units of the following type (formula in square brackets):
• the calculation is based on the assumption that half of the NCO groups of the polyurethane prepolymer react with water with CO2 elimination to form amino groups, which then react with the second half of the NCO groups to form isolated urea bridges with an increase in molecular weight.
• the dispersions of the invention have particle diameters, determined, for. B. by laser correlation spectroscopy measurements, from 20 to 600, preferably from
• the solids content of the dispersions is at least 30, preferably at least 35%.
• the pH of the dispersion is below 8.5, preferably below 7.8.
• the average molecular weights Mn of the dispersion are> 20,000, preferably> 30,000 and very particularly preferably> 40,000 g / mol (determined, for example, by gel permeation chromatography).
• the dispersion contains proportions of very high molecular weight fractions which are no longer completely soluble in organic solvents and which then cannot be determined from a molecular weight.
• the products according to the invention are suitable for coating or varnishing any substrates, in particular wood, ceramic, stone, concrete, bitumen, hard fiber, glass, porcelain, plastics and metallic substrates of all kinds. They can also be used as a finish or finish for textile and leather coatings.
• the preferred area of application is vehicle painting, especially as a barrier layer with a high level of stone chip protection and excellent water resistance.
• the customary auxiliaries and additives can be added to them.
• these include, for example, inorganic or organic pigments, fillers such as carbon black, silica, talc, chalk, silica, kaolin, glass as powder or in the form of fibers, cellulose or cellulose acetobutyrate, and crosslinking agents such as blocked polyisocyanates, polyisocyanates, melamine resins, urea resins, Urea-
• Aldehyde resins carbodiimides, carbamates, tris (alkoxycabonylamino) triazines, carbamate-modified amino crosslinking resins.
• the crosslinking agents can be used in water-dispersible or non-water-dispersible form.
• suitable polyisocyanates on which the blocked polyisocyanates are based are cycloaliphatic or aliphatic polyisocyanates such as hexamethylene diisocyanate (HDI), l-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (isophorone diisocyanate, IPDI), methylene-bis- (4- isocyanatocyclohexane), tetramethyl-xylylene diisocyanate (TMXDI).
• Polyisocyanates which contain heteroatoms in the radical containing the isocyanate groups are particularly suitable.
• Examples of these are carbodiimide groups, allophanate groups, isocyanurate groups, urethane groups and polyisocyanates containing biuret groups.
• the known polyisocyanates which are mainly used in the production of paints, e.g. B. biuret, isocyanurate or uretdione groups containing modification products of the above simple polyisocyanates, especially hexamethylene diisocyanate or isophorone diisocyanate.
• Low molecular weight polyisocyanates containing urethane groups are suitable, as can be obtained by reacting excess IPDI or TDI with simple polyhydric alcohols in the molecular weight range 62-300, in particular with trimethylolpropane or glycerol. It is also possible to use any mixtures of the polyisocyanates mentioned for the preparation of the inventive
• Suitable polyisocyanates are also the known prepolymers containing terminal isocyanate groups, as are obtainable in particular by reacting the simple polyisocyanates mentioned above, especially diisocyanates, with inadequate amounts of organic compounds having at least two functional groups which are reactive toward isocyanates.
• the isocyanate groups of the polyisocyanates are blocked.
• Conventional compounds such as are used, for example, in the paint sector can be used as blocking agents.
• suitable blocking agents are dimethyl malonate, diethyl malonate, ethyl acetoacetate, caprolactam, secondary aliphatic amine, butanone oxime, 3,5-dimethylpyrazole.
• the blocked polyisocyanates described can be used in non-hydrophilic form, the conversion into the aqueous dispersion e.g. can be accomplished by mixing and dispersing together with the polyurethane prepolymer.
• the polyurethane dispersion according to the invention can also be used as a polymeric emulsifier for crosslinking agents which are not water-dispersible on their own. It is also possible to add a hydrophilized, water-dispersible or blocked polyisocyanate already present in water-dispersible form to the polyurethane dispersion according to the invention.
• Hydrophilized blocked polyisocyanates are known and z. B. described in EP-A-0 566 953.
• Reactive amino crosslinking resins or melamine resins such as Cymel® 328 (Cytec) or / and trisalkoxycarbonylaminotri- azines such as TACT® (Cytec) and / or reactive, for example malonic ester-blocked polyisocyanate crosslinking agents and / or urethanized melamine resins.
• polyurethane dispersions according to the invention can be combined with other binders.
• the combination with water-soluble or water-insoluble melamine resins and water-emulsifiable or water-dispersible polyester resins or polyester-polyurethane resins is preferred.
• the processing of the dispersion to produce coatings by any method, for example by brushing, pouring, spraying, dipping, rolling or
• the dispersions according to the invention are e.g. suitable for the production of paints, coatings, sealants and adhesives.
• the products obtained by various application techniques can be dried at room temperature or at an elevated temperature of up to 200 ° C., preferably at 60-150 ° C.
• the application is preferably carried out by spraying and drying preferably for 5 to 10 minutes at 50 to 80 ° C.
• the dry film layer thickness can be, for example, 15-50 ⁇ m, but coatings with a higher layer thickness are possible.
• the coating can be highly elastic, but depending on the requirement profile, it can also be set hard.
• the barrier layer can be sanded and painted over very well. After painting over with a basecoat / clearcoat or a pigmented topcoat then a common burn-in process takes place, e.g. B. for 20-25 minutes at 120-160 ° C.
• the coating produced in this way has optically and mechanically comparable or better results than a lacquer structure in which, instead of the barrier layer, a filler used as usual with e.g. B. 35 - 45 microns dry film thickness with its own baking process of z. B. 20 - 25 minutes at 135 - 165 ° C and additionally basecoat / clear coat or top coat.
• a filler used as usual with e.g. B. 35 - 45 microns dry film thickness with its own baking process of z. B. 20 - 25 minutes at 135 - 165 ° C and additionally basecoat / clear coat or top coat.
• the dispersions of the invention can be mixed with other ionic or nonionic dispersions or aqueous solutions, e.g. B. with polyester, polyvinyl acetate, polyethylene, polystyrene, polybutadiene, polyurethane, polyvinyl chloride, polyester-polyacrylate, polyacrylate and copolymer dispersions or solutions. It is also possible to add known, chemically unfixed, preferably ionic emulsifiers.
• Lacquers for barrier layers according to the invention contain, in addition to additives and auxiliaries customary in automotive painting, and optionally water for adjusting the spray viscosity
• the lacquers for barrier layers according to the invention have solids contents of at least 45%, preferably at least 50%, with application viscosity and, even in the presence of highly reactive crosslinking agents for stoving lacquers, for example based on melamine resin, show very good viscosity stability during storage.
• the barrier layers prepared from the dispersions according to the invention have excellent stone chip resistance and very good adhesion or interlayer adhesion.
• the polyurethane dispersions according to the invention can also be used to produce reactive stoving lacquers, in particular stoving fillers, which can be cured at low temperatures. They are preferably combined with the above-mentioned reactive crosslinking resins and, where appropriate, other polymers in such a way that coatings which can be cured at from 90 to 120 ° C. are optionally obtained using suitable catalysts and the customary pigments, additives and auxiliaries.
• the pigment paste is produced from the following raw materials by grinding on a bead mill: 42.2 g Bayhydrol® D270 (water-dispersible polyester resin, 70% dissolved in organic solvents, Bayer), 82.4 g distilled water, 6 g 10% aqueous solution of dimethylethanolamine, 5.4% of a 50% solution of Surfynol® 104 (wetting agent, Air Products) in NMP, 5.4 g Additol® XW 395 (Vianova Resins), 108.2 g Bayertitan® R-FD -I (titanium dioxide, Bayer),
• barrier layer 3 20 ⁇ m dry film thickness, 10 minutes 70 ° C drying,
• Intermediate liability barrier topcoat grades from 1 to 3, 1 is very good, 3 is bad
• Intermediate liability barrier-KTL grades from 1 to 3, 1 is very good, 3 is bad
• a film with 20 ⁇ m is used to check the water resistance of the barrier layer
• Film hardness 58 pendulum seconds (according to König) solvent resistance (test of releasability after one minute of exposure to the following
• Solvents toluene, methoxypropylacetate, ethyl acetate, acetone, rating 0 to 5, 0 is unchanged, 5 is removed): 2/2/2/2/2
• Dispersion 1 fulfills all requirements placed on a barrier layer.
• Application example 4) (comparison):
• a liability or stone chip protection test in the paint structure is not possible.
• the comparative product is unsuitable as a barrier layer, and solvent resistance and, above all, film hardness and water resistance are inadequate.
• Example 3 using comparative dispersion 5) instead of dispersion 1), a lacquer for a barrier layer is produced, corresponding coatings are applied and cured, and the properties are tested.
• a coating for a barrier layer is produced using comparative dispersion 7) instead of dispersion 1), appropriate coatings are applied and cured, and the properties are tested.
• Appearance of the coating after application limited in order. (The basecoat bursts open after drying for 5 minutes at 80 ° C).
• the comparative example is unsuitable as a barrier layer because no homogeneous paint structure is achieved and the film hardness, but above all the water resistance, is inadequate.
• Example 9 (according to the invention): In a dry 2-1 reaction vessel with stirring, cooling and heating device
• a varnish for a barrier layer 10 is produced from 117 g of pigment paste A) , 195 g of dispersion 9), 9.8 g of amino crosslinking resin (®Cymel 328, Cytec) and 8 g of distilled water.
• the varnish has a pH of 7.5, a solids content of 50.3% and an ISO 5 cup run-out time of 21 seconds. After the paint had been stored at room temperature for 14 days, the viscosity rose only slightly (27 seconds).
• 160 g of an aliphatic polycarbonate diol (Desmophen® 2020, Bayer AG, mol weight 2000), 120 g of a polyester diol based on adipic acid, hexanediol, neopentyl glycol (mol weight 2000) are placed in a dry 2-1 reaction vessel with a stirring, cooling and heating device ) and 19.6 g of dimethylolpropionic acid are weighed in under a nitrogen atmosphere. 6.70 g of trimethylolpropane, 225 g of acetone and 10.4 g of ethyldiisopropylamine (degree of neutralization 55%) are then added and the mixture is heated to 65.degree.
• the paint has a pH of 7.4, a solids content of 50.5% and an ISO 5 cup run-out time of 16 seconds. After the paint had been stored at room temperature for 14 days, the viscosity rose only slightly (18 seconds).
• Film hardness 53 pendulum seconds (after König) Resistance to solvents (test of solubility at one minute exposure to X / Y / Z / W,
• Dispersion 11 meets all requirements.
• 272 g of an aliphatic polycarbonate diol (Desmophen® 2020, Bayer AG, molecular weight 2000), 272 g of a polyester diol based on adipic acid, hexanediol, neopentyl glycol (molecular weight 1700) and.
• 272 g of a polyester diol based on adipic acid 272 g of a polyester diol based on adipic acid, hexanediol, neopentyl glycol (molecular weight 1700) and.
• a stirring, cooling and heating device Weighed 26.8 g of dimethylolpropionic acid under a nitrogen atmosphere and heated to 65 ° C.
• a varnish for a barrier layer 10 is produced from 11 g of a pigment paste A> , 209 g of dispersion 13), 9.8 g of amino crosslinking resin (Cymel® 328, Cytec) and 8 g of distilled water.
• the varnish has a pH value of 7.5, a solids content of approx. 49% and a run-off time in the ISO 5 cup of 15 seconds. After the paint had been stored at room temperature for 14 days, the viscosity rose only slightly (17 seconds).
• Dispersion 13 fulfills all requirements, however, due to the reduced content of dimethylolpropionic acid, the film hardness in the lower range is acceptable

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• 2000
  • 2000-02-14 BR BR0008492-1A patent/BR0008492A/pt not_active Application Discontinuation
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  • 2000-02-14 AU AU28047/00A patent/AU2804700A/en not_active Abandoned
  • 2000-02-14 WO PCT/EP2000/001205 patent/WO2000050482A1/de not_active Ceased
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  • 2000-02-14 JP JP2000601058A patent/JP2002537454A/ja active Pending
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  • 2000-02-14 DE DE50001375T patent/DE50001375D1/de not_active Expired - Lifetime
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  • 2000-02-23 AR ARP000100765A patent/AR022724A1/es active IP Right Grant
• 2011
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