DE19634721A1 - Lacquer coatings e.g. for motor cars, laminates or food or drink tins - Google Patents

Abstract

A coating material (M) containing a modified polyester (A) that contains fluorine atoms is prepared by reacting a polyester (B) containing carboxyl groups with at least one reaction product (C) containing free epoxy groups. (C) is obtained by reacting (C1) epoxy compounds with at least two epoxy groups, epoxy resins with more than one epoxy group per molecule and/or acrylic copolymer with more than one epoxy group per molecule, with (C2) fluorine-containing carboxylic acids, fluorine-containing carboxylic acid anhydrides, dicarboxylic acid hemiesters of fluorine-containing monovalent alcohols and dicarboxylic acids or their anhydrides and/or perfluorocarboxylic acids of formula F-(CF2)n-COOH (I) (n = 5-21). The reaction between (B) and (C) may optionally be carried out in the presence of phosphoric acid, fluorine-free carboxylic acids, fluorine-free carboxylic acid anhydrides, hemiesters of polycarboxylic acids or their anhydrides with monovalent alcohols, (poly)glycol ethers and/or fatty alcohols.

Description

The invention relates to solvent-free, solvent-containing, water thinnable or powder coating materials containing fluorine containing modified polyester and the use of the coating medium. In general, those contained in the coating compositions modified polyester has a fluorine content of 0.01 to 10 wt .-%, preferably at least 0.2% by weight of fluorine and very particularly preferably more than 0.5% by weight Fluorine, on.

These coating compositions can work together depending on their total settlement physically drying, oxidative drying and / or moisture curing, cold curing, especially as a two-component system, thermosetting and / or be radiation-curable and can be analogous to known coatings means, e.g. B. on the basis of polyesters, polyester acrylates, polycarbonate diols, polybutadiene polyols, polyester urethane acrylates, polyester urethane resins, combinations of polyester or polyester urethane resins with amino plastic and / or reversibly blocked polyisocyanates, so that no further explanations are necessary.

The production of fluorine-containing polyesters is state of the art and mentioned for example in WO-91/09025 and the literature cited therein. Coating agents, especially of the type claimed, cannot be removed.

DE-44 18 309 A1 describes water-soluble perfluoroalkyl groups Liche, -emulsifiable or -dispersible resins based on the reaction from

• a) Perfluoroalkyl groups containing defined sulfonamides (general Formula),
• b) Components with oxyethylene units and reactive towards 1,2-epoxides Groups, according to claim 1 also an acid group-containing, polyoxyalkylene modified polyester containing oxyethylene units is used,
• c) a component which contains 1,2-epoxy groups and
• d) optionally further components which are reactive towards 1,2-epoxides Have groups, with the proviso that the amount of those present in the resin Oxyethylene units is 5 to 95% by weight of the total resin.

The resins are used as a treatment, protection and impregnation agent for rock materials, textile materials, leather and paper as well as emulsifying, wetting and auxiliaries for the preparation of aqueous perfluoroalkyl compounds of the preparations used (claim 5).

In the examples, polyether esters are used and the resins according to Bei games 1 to 7 have a fluorine content of 29.3 to 43.9% by weight and cannot be painted over due to the high fluorine content (anti-graffiti Equipment, cf. P. 5, line 33), which in practice means that these resins for conventional coating agents, e.g. B. in automotive painting, lack missing, but always necessary refinishing option, not are operational. In addition, these resins are not thermosetting. Also from the description, the examples and the claims (cf. e.g. claim 5) there is no other matter.

The object of the invention is therefore seen in coating agents according to the above and following statements and the claims for ver to provide, which is analogous to known solvent-free, Solvent-based, water-dilutable or powder coating Allow medium to be used, however due to the fact that it contains all or part of it tendency to improve modified polyester containing fluorine Coatings, e.g. B. with respect to chemicals, water and weather resistant , trouble-free formation of coatings.

Subject of the invention are coating compositions according to the above and the following explanations and claims as well as the use of the bean said coating agents.

For the production of those contained in the coating compositions according to the invention Modified polyester can be used by everyone in paint technology from numerous Publications known carboxyl-containing polyesters, e.g. B. sown saturated or unsaturated polyesters, or known per se, already with other common modifiers, e.g. B. styrene, vinyl toluene, alkyl (meth) acrylates, hydroxyalkyl (meth) acrylates, diisocyanates, modified poly esters are assumed, such as those in DE-OS 39 33 890 mentioned or described. Of course, these can be polyesters in addition to the carboxyl groups, other functional groups, e.g. B. NH₂ and / or NH groups, e.g. B. according to DE-OS 39 33 890, acetoacetate groups, in particular Hydroxyl groups. The carboxyl groups of the polyesters can be made from polycarboxylic acids not completely reacted with polyols in the polyester production or use of hydroxycarboxylic acids, especially dimethylol propionic acid, or in the usual way by partial reaction of hydroxyl-containing polyesters with polycarboxylic acids or their An hydrides, especially trimellitic anhydride, hexahydrophthalic anhydride, Succinic anhydride, maleic anhydride, tetrahydrophthalic anhydride, getting produced.

In the manufacture of automotive clearcoat or transparent topcoats for the well-known multi-layer coating (coloring basecoat + clearcoat / trans Parent top coat, especially with joint hardening of the base layer and clear coat) is made of aliphatic or cycloaliphatic carboxyl group-containing polyesters, preferably those using Cyclo hexanedicarboxylic acids or their anhydrides, e.g. B. 1,4- and / or 1,3-cyclohexane dicarboxylic acid and / or hexahydrophthalic anhydride, and aliphatic and / or cycloaliphatic polyols, e.g. B. neopentyl glycol, trimethylol propane, Cyclohexanedimethanol, diols based on hydrogenated bisphenol A, herge were z. B. according to WO-95/01407 or EP-0 706 546.

For the production of laminates, in particular glass fiber reinforced starting from unsaturated polyesters which are customary per se.  

The reaction products claimed according to the invention for reaction with the above-described carboxyl-containing polyesters, preferably with an acid number of 10 to 200, in particular 40 to 100, and optionally further functional groups, in particular with a hydroxyl content of at least 3%, are characterized by Implementation of epoxy compounds with at least two epoxy groups, e.g. B. in the literature, z. BM Paquin, epoxy compounds and epoxy resins, Springer-Verlag, Berlin / Göttingen / Heidelberg, 1958, EP-0 617 726, EP-0 447 360, described epoxy compounds, in particular commercially available diepoxides, such as liquid epoxy resins based on bisphenol A at room temperature, aliphatic or cycloaliphatic epoxy resins, in particular based on cyclohexanedi methanol, hexahydrophthalic acid diglycidyl ester, 3,4-epoxy-6-methyl-cyclohexyl methyl-3,4-epoxy-6-methylcyclohexane carboxylate, triglycidyl isocyanurate, and / or epoxy resins with more than one epoxy group Average molecular weight, e.g. B. at room temperature solid epoxy resins based on bisphenol A, and / or acrylic copolymers with more than one epoxy group per average molecular weight, in particular with at least two epoxy groups per average molecular weight, preferably with an average molecular weight below 5000, especially below 3000, z. B. using an appropriate amount of glycidyl (meth) acrylate and / or other epoxy (meth) acrylates, e.g. B. according to DE-OS 195 37 887, and / or allyl glycidyl ether Herge provided acrylic copolymers, which may optionally also contain hydroxyl groups, and fluorine-containing carboxylic acids or their anhydrides, preferably fluorine-containing aromatic carboxylic acids or their anhydrides, for. B. fluorobenzoic acid, 4,5-difluorophthalic anhydride, and / or half-esters of fluorine-containing monohydric alcohols, e.g. B. 2-fluoroethanol, 3-fluoro benzyl alcohol, preferably 2,2,2-trifluoroethanol, and dicarboxylic acids or their anhydrides, e.g. B. succinic anhydride, maleic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, preferably hexahydrophthalic anhydride, and / or perfluorocarboxylic acids of the general formula F- (CF₂) _n -COOH, where n is an integer from 5 to 21, preferably per- or pentadeca-fluoroctanoic acid , optionally with the use of phosphoric acid and / or fluorine-free carboxylic acids or their anhydrides, for. As acrylic acid, methacrylic acid, methacrylic anhydride, crotonic acid, aliphatic monocarboxylic acids with at least 7 carbon atoms, for. B. pelargonic acid, cyclo aliphatic, heterocyclic or aromatic monocarboxylic acids, for. B. furan carboxylic acid, cyclohexanol carboxylic acid, cyclohexanone carboxylic acid, adamantane carboxylic acid, abietic acid, nicotinic acid, benzoic acid, polycarboxylic acids or their anhydrides, half esters of polycarboxylic acids or their anhydrides and monohydric alcohols, glycol or polyglycol ethers or fatty alcohols.

In the production of these reaction products, they are usually also known for the implementation of fluorine-free carboxylic acids or their anhydrides Process for reaction with the epoxy compounds applied, e.g. B. according DE-OS / DE-PS 17 95 852 or 17 45 053 or other patents, e.g. B. solvent-free implementation or in the presence of organic solvents carried out at temperatures from 35 to 180 ° C, preferably 120 up to 150 ° C, optionally under pressure and / or inert atmosphere, e.g. B. N₂, and / or in the presence of suitable catalysts for the epoxy / carboxy reaction,  e.g. B. alkali metal hydroxides, e.g. B. lithium hydroxide monohydrate, sodium carbonate, Organometal salts, e.g. B. lithium octoate, tertiary amines, triethylbenzylammonium chloride, phosphines, these catalysts usually in an amount from 0.1 to 5% by weight, preferably 0.1 to 1% by weight, based on the reactants ten are used. When implementing the epoxy compounds with the claimed perfluorocarboxylic acids, it may be advantageous to be as low as possible temperatures, especially below 100 ° C.

The reaction of the carboxyl-containing polyester, preferably with a Average molecular weight below 5000, in particular from 500 to 3000, with the reaction products takes place at elevated temperature, for. B. 60 to 160 ° C, in particular 80 to 130 ° C, in the melt or in the presence of orga African solvent, e.g. B. xylene, optionally in an inert atmosphere and / or in the presence of customary catalysts for the epoxy / carboxy reaction.

The claimed contained in the coating compositions of the invention Polyesters preferably have functional groups, very particularly preferably Carboxyl and / or hydroxyl groups, which are used for crosslinking with conventional ver wetting agents are suitable and contain z. B. Epoxy compounds, β-hydroxyalkylamides, polycarboxylic acids or their anhy dride, aminoplasts and / or polyisocyanates and / or reversibly blocked Polyisocyanates.

The coating compositions according to the invention preferably contain Ver wetting agents in whole or in part with monohydric alcohols, e.g. B. methanol and / or butanol, etherified aminoplasts and / or carboxyl group-containing Derivatives of fully or partially etherified aminoplasts, their use in coating compositions the skilled worker is familiar with, e.g. B. urea and / or Aminotriazine-formaldehyde resins, preferably with methanol and / or butanol fully or partially etherified melamine-formaldehyde resins, hexamethoxymethyl melamine, tetramethoxybenzoguanamine, tetramethoxymethylglycoluril, carboxyl group-containing reaction products of hexamethoxymethylmelamine and polycarbonate acid anhydrides, e.g. B. according to DE-PS 35 37 855, and / or polyisocyanates, the Use in coating compositions is also quite familiar to the person skilled in the art is preferably polyisocyanates based on trimerized hexamethy Lendiisocyanat or trimerized isophorone diisocyanate, and / or the expert also common blocked polyisocyanates, preferably those that in Journal of Coatings Technology, March 1995, Vol. 67, No. 842, page 33-40, and in Farbe & Lack, issue July 1996, pages 51-58, e.g. B. with methanol blocked tetramethylxylylene diisocyanate (TMXDI) or isophoronediiso mixed blocked with 3,5-dimethylpyrazole and 1,2,4-triazole cyanate isocyanurate.

The coating compositions of the invention can in addition to the claims other polyesters, e.g. B. polyurethane resins, polyester urethane resins, phenolic resins, polyesters other than those claimed, e.g. B. on the Based on caprolactone polyols, epoxy resins or modified epoxy resins, Acrylic copolymers, preferably with hydroxyl and / or epoxy groups also in the form of their solution, emulsion or dispersion in water, e.g. B. aqueous polyurethane dispersions, preferably in Kombina tion with crosslinking agent of the type described above.  

The paint raw materials and paint technology suitable for combination with polyesters Compatibility tests are just as familiar to the person skilled in the art as the quantities ratios of the components and the composition of coating agents for the respective purpose and therefore no longer need to be explained will.

The coating compositions of the invention can be used as a function of their composition analogous to known coating compositions on the Use base of polyesters and this is based on the literature, for example refer to the explanations in DE-OS 39 33 890, column 1, lines 47-68, and ff. Column 2, lines 1-39.

The solvent-free solvents according to the invention are preferably containing, water-dilutable or powdered coating agents composed that they are thermosetting, e.g. B. at temperatures from 60 to 180 ° C and in the case of coil coating processes also briefly at metal temperatures up to about 250 ° C, e.g. B. 10s / 230 ° C.

A particular use of the coating compositions according to the invention is for the production of coatings or coatings in the coil coating process (Coil coating) or for the production of coatings during painting of packaging containers, e.g. B. cans or drinks cans, or for forth provision of automotive paints, especially transparent top coats or Clear coats for multi-layer coating, with the transparent top coat or clear varnish on a vented or pre-dried base layer What base layer and top coat or clear coat layer together be branded. For example, a powder clear coat based an epoxy group-containing acrylic copolymer as a crosslinking binder component one or more of the claimed polyesters with carboxyl groups contain.

Special uses of the coating compositions according to the invention are also the production of chemical-resistant polyurethane varnishes in combination with polyisocyanates or blocked polyisocyanates, in particular from 2K systems, e.g. B. with commercially available "paint polyisocyanates" based on trimerized hexamethylene diisocyanate and / or trimerized Iosphorondi isocyanate, or the production of laminates, especially glasfaserver strengthened, by means of coating agents according to the invention, the stressed saturated polyester, dissolved in styrene.

The content of the claimed polyester in the coating according to the invention funds can fluctuate within wide limits, as can be seen from the previous standing statements results and is among other things from the purpose of the Coating agent and the fluorine content of the claimed therein Depending on polyester.  

The coating compositions of the invention can, for example, a bean said polyester, which is modified with drying fatty acids (fluor containing drying alkyd resin), as an oxidative drying self-binding contain agents, or coating agents according to the invention for radical Networking, e.g. B. by means of peroxides and catalysts or by means of Photoini UV curing tiators contain as an essential binder component unsaturated claimed polyester, dissolved in suitable monomers, e.g. B. Styrene, hexanediol diacrylate, tripropylene glycol diacrylate.

On the other hand, coating agents according to the invention can claim poly esters only in minor amounts, e.g. B. less than 10 wt .-%, based on binders, especially to ensure trouble-free training Surfaces of coating compositions according to known composition to effect the order.

Of course, the coating compositions according to the invention can also usual additives and auxiliaries, e.g. B. pigments, graphite, fillers, solutions medium, water, drying agents, e.g. B. cobalt octoate, hardener, e.g. B. acid hardeners, e.g. B. p-toluenesulfonic acid, also in blocked form, neutralizing agent, e.g. B. tertiary amines, catalysts or accelerators for crosslinking cracks ions, organic metal compounds, e.g. B. metal chelates, e.g. B. Titanyl acetylacetonate, dibutyltin dilaurate, dispersant, rheology aid, e.g. B. thickening and thixotropic agents, e.g. B. hydrophobicized pebbles acid, polyurethanes, copolymers, e.g. B. based on (meth) acrylic acid, Polymerization initiators, e.g. B. peroxides, photoinitiators, e.g. B. on the Base of benzophenone, UV absorber, e.g. B. based on benzotriazole, HALS (hindered amine light stabilizer) compounds, reactive thinners, e.g. B. Diacrylates, polyols, surfactants, e.g. B. fluorosurfactants, silicone oil, included.

The coating compositions of the invention can be applied to substrates according to usual methods, e.g. B. painting, spraying, dipping, rolling, electro static order.

Metal, wood or plastic are particularly suitable as substrates, whether probably also other substrates, e.g. B. paper, textile materials come.

The following examples serve to supplement the description and claims play the further explanation of the invention, without the claim to full to raise consistency. The parts specified are parts by weight.

Preparation of the reaction product R

In a conventional apparatus, 100 parts of a commercially available room temperature liquid epoxy resin based on bisphenol A and epichlor hydrine with a molecular weight of 700 and an epoxy value of 0.53-0.55 ("Eurepox 730" from Schering AG, Bergkamen DE) and 15 parts of perfluorooctanoic acid ("Fluorad acid FC-26" from 3M-Company, European Technical Center, Zwÿndrecht, Belgium) using 0.2 part of tetraethylammonium bromide as a catalyst at 90 to 100 ° C taking into account the initially exothermic reaction until Acid number of 4.8 implemented. The reaction product is practically colorless Resin that is still flowable at room temperature with a fluorine content of 8.98 % By weight.

Production of the fluorine-containing modified polyester F

A 83% solution of the carboxyl-containing polyester D according to DE-PS 38 11 497 in a mixed solvent of butyl glycol and n-butanol in Weight ratio 5: 2 with 8 parts of the reaction product R in one usual equipment at 90 to 100 ° C using 0.1 part of lithium hydroxide monohydrate and 0.1 part tetraethylammonium bromide as catalysts implemented up to the acid number of 36. The almost colorless end product (fluor. Ent modified modified polyester in solution) has a solids content 84.3% by weight and a fluorine content of 0.79% by weight (solid resin). Diluted with xylene to a solids content of approx. 60.7% by weight the viscosity 56 s / DIN 4 mm / 21 ° C.

example 1

100 parts of the above solution of the modified polyester F are with 25 parts of hexamethoxymethylmelamine mixed and diluted with 42 parts of xylene. Solids content approx. 65.6% by weight, viscosity 53 s / DIN 4 mm / 21 ° C. After this Application on aluminum sheet in a dry film thickness of approx. 5 µm and baking for 10 min / 180 ° C results in a colorless, glossy hard elastic coating that deforms around the sheet thickness without cracking leaves.

Example 2

60 parts of the above solution of the modified polyester F are with 5 parts of 2- (dimethylamino) ethanol neutralized, with 10 parts of desalted Diluted water and mixed with 15 parts of hexamethoxymethylmelamine, followed by is diluted with 110 parts of demineralized water. The aqueous colloidal Solution (Tyndall effect) has a solids content of approx. 32.8% by weight pH around 8.8 and a viscosity of 183 s / DIN 4 mm / 20 ° C. Immediately after Apply to degreased steel sheet in a dry film thickness of approx. 20 µm is baked for 15 min / 160 ° C. The result is a colorless high shiny coating that deforms around the sheet thickness without cracking leaves.

Claims (8)

1. Coating agent containing modified fluorine-containing Polyester, can be produced by reacting a poly containing carboxyl groups esters with a reaction containing at least one free epoxy group product from the reaction of epoxy compounds with at least two epoxies groups and / or epoxy resins with more than one epoxy group per through average molecular weight and / or acrylic copolymers with more than one Epoxy group per average molecular weight and fluorine-containing carbon acids or their anhydrides and / or dicarboxylic acid half-esters of fluorine monohydric alcohols and dicarboxylic acids or their anhydrides and / or perfluorocarboxylic acids of the general formula F- (CF₂) -COOH, where n is a integer from 5 to 21 means, if necessary, our joint use of Phosphoric acid and / or fluorine-free carboxylic acids or their anhydrides and / or Half-esters of polycarboxylic acids or their anhydrides and monovalent Alcohols, glycol ethers, polyglycol ethers and / or fatty alcohols. 2. Coating composition according to claim 1, characterized in that the contains modified polyester contains 0.01 to 10 wt .-% fluorine. 3. Coating composition according to claims 1 and 2, characterized in that the modified polyester contains perfluoroalkyl groups. 4. Thermosetting coating composition according to claims 1 to 3, characterized characterized in that the modified polyester carboxyl and / or Has hydroxyl groups. 5. Coating composition according to claims 1 to 4, characterized in that there are also other resins and, where appropriate, conventional crosslinking agents and / or contains conventional additives and auxiliary substances. 6. Coating composition according to claim 5, characterized in that it is poly esters, acrylic copolymers, polyurethane resins and / or polyester urethane resins contains. 7. Coating composition according to claims 1 to 6, characterized in that that it is a completely or partially etherified aminoplast and / or or their carboxyl-containing derivatives and / or polyisocyanates and / or contains reversibly blocked polyisocyanates. 8. Use of the coating compositions according to claims 1 to 7 for Her Provision of automotive paints or for the production of coatings in the band painting process or for the production of chemical-resistant coatings or for the production of laminates.