WO2005090494A1 - Cer compounds used as initiators for thermal hardening - Google Patents

Abstract

The invention relates to coating materials containing at least one Cer(IV) compound, optionally at least one non-aqueous solvent, at least one radically polymerisable compound, and optionally other paint-specific additives.

Description

Cerium compounds as initiators for thermal hardening

description

The present invention relates to the use of cerium compounds as initiators for radiation curing and coating compositions which contain cerium compounds.

Mixtures of cerium salts and polymerization inhibitors are known systems for stabilizing ethylenically unsaturated compounds against undesired polymerization, for example from US Pat. No. 4,542,231.

No. 3,755,234 describes the graft or block polymerization of polyvinyl alcohols in the presence of tetravalent cerium compounds. The polymerization is thermally induced and takes place at elevated temperatures of 40 - 65 ° C.

Acidic, aqueous solutions are disclosed as solvents for the cerium compounds; the aim is to carry out the polymerization at a pH below 6.0, preferably below 3.0.

WO 94/24207 describes the graft polymerization of ethylenically unsaturated compounds onto active hydrogen-containing compounds using peroxides as radical polymerization catalysts which are activated by metal ions, such as, for example, Ce ⁺ or Ce ³⁺ . A combination of peroxide and heavy metal ions, including cerium salts, for starting a graft polymerization is also disclosed in DE-A1 198 06745.

Here the cerium compound does not function as a polymerization initiator but as an activator for the actual catalyst, the peroxide. , K. Das, D. Basu and A. Banerjee describe in Journal of Applied Polymer Science, 1999, 72, 135-140 the influence of exposure on the graft polymerization of methyl methacrylate (MMA) on viscose. Accordingly, the grafting of MMA on viscose is increased by irradiation by the presence of a Ce ⁺ / Ti ³⁺ system or Ce ⁴⁺ in acidic solution.

A disadvantage of all the disclosures described above is that acid cannot be used as a solubilizer for the cerium compounds in paint coatings, since this deteriorates weather resistance and heat resistance, as described, for example, in US Pat. No. 3,755,234, column 2, line 57 to column 3, line 15. The addition of water leads to phase separation in organic coating compositions, so that the cerium acting as initiator accumulates in the aqueous phase instead of the organic one, where it is to initiate, or to emulsions which cloud the coating compositions , It was an object of the present invention to provide coating compositions in which cerium can be used as a radical initiator and can be distributed uniformly in the coating composition.

The object was achieved by coating compositions comprising at least one cerium (IV) compound, optionally at least one non-aqueous solvent, at least one compound capable of free radical polymerization and ^“ optionally further additives typical of lacquer.

According to the invention, cerium (IV) compounds are used to initiate radical polymerization.

According to the invention, the absence of water in the coating composition according to the invention, i.e. the proportion of water according to the invention must be 10% by weight or less, preferably 5% by weight or less, particularly preferably 3% by weight or less, very particularly preferably 2% by weight or less, in particular 1% by weight or less and especially 0.5% by weight or less.

If water is present in the coating composition within these limits, the pH of the aqueous phase should be from 6.0 to 8.0, preferably from 6.5 to 7.5.

The coating composition is preferably used for statistical, radical (co) polymerization.

Cerium (IV) compounds for the purposes of this invention are those compounds which contain at least one Ce ⁴⁺ cation with any counterions.

Possible counterions are F ^~ , CI ^" , CIO ^" , CIO ₃ ^" , CIO ₄ ^" , Br ^" , J ^" , JO ₃ ^" , CN ^" , OCN ^" , SCN ^" , NO ₂ ^" , NO ₃ -, HCO ₃ -, CO ₃ ² -, S ² -, SH ^" , HSO ₃ ~, SO ₃ ^2" , HSO-f, SO ₄ ^{2 "} , S ₂ O ₂ ² -, S ₂ O ₄ ^2" , S ₂ O ₅ ² -, S ₂ O _e ² -, S ₂ O ₇ ^2_ , S ₂ O ₈ ² -, H ₂ PO ₂ -, H ₂ PO ₄ ^" , HPO ₄ ^2" , PO PjOΛ dithiocarbamate, salicylate, ( OCpH ₂ p ₊ ι) ^~ , (CpHap-iOj) -, (CpHzp-sO∑) ^" and (C _{p + 1} H ₂ p_ ₂ O ₄ ) ^2" , where p stands for the numbers 1 to 20, methanesulfonate ( CH ₃ SO ₃ ^' ), trifluoromethanesulfonate (CF ₃ SO ₃ ^' ), toluenesulfonate (CH ₃ CβH ₄ SO ₃ ^" ), benzenesulfonate (CeHsSOs ^" ), hydroxide (OH ^" ), anions of aromatic acids such as benzoic acid, phthalic acid, and the like and 1,3-dicarbonyl compounds. Carboxylates may also be mentioned, in particular formate, acetate, propionate, hexanoate and 2-ethylhexanoate and oxalate, acetylacetonate, acrylate and methacrylate, preferably formate, acetate, propionate, oxalate, acetylacetonate, acrylate and methacrylate.

These salts can also be present as hydrates, which are equally suitable.

Preferred cerium (IV) compounds are ammonium hexanitrate cerate (IV) (cerium (IV) ammonium nitrate, (NH ₄ ) ₂ [Ce (NO ₃ ) β]), sodium hexanitrate cerate (IV) (Na ₂ [Ce (NO ₃ ) ₆ ]) , Potassium hexanitrate cerate (IV) (K ₂ [Ce (NO ₃ ) ₆ ]), cerium (IV) ammonium sulfate (Ce (NH ₄ ) ₂ (NO ₃ ) ₆ )), cerium (IV) hydroxide, cerium (IV) isopropylate Isopropanol complex, cerium (IV) oxide (CeO ₂ ) and cerium (IV) sulfate (Ce (SO ₄ ) ₂ ).

Of course, it is also possible to use cerium compounds with an oxidation state lower than +4 and to convert them into a cerium (IV) compound in the coating composition with the aid of an oxidizing agent, in particular cerium (III) compounds.

Preferred cerium (III) compounds are cerium (III) acetate, cerium (III) hydrate, cerium (III) acetylacetonate, cerium (III) acetylacetonate hydrate, cerium (III) bromide, cerium (III) carbonate, cerium (III) ) carbonate hydrate, cerium (HI) chloride (CeCI ₃ ), cerium (III) chloride heptahydrate, cerium (III) ethylhexanoate and its solutions or dispersions in mineral oil or naphtha (Octa Soliogen Cerium® 6 and 10 d. from Borcherts, Monheim, Germany, CAS number [58797-01-4]), cerium (III) fluoride, cerium (III) nitrate (Ce (NO ₃ ) ₃ ), cerium (III) nitrate hexahydrate, cerium (III) oxalate, cerium (III) sulfate, cerium (III) sulfate octahydrate, cerium (III) oxide or cerium (III) acrylate.

According to the invention, suitable oxidizing agents are those which in turn do not trigger any polymerization, i.e. are not radical formers.

However, it is preferred to use the cerium compounds as cerium (IV) compounds.

The cerium compounds can also be used as complexes, for example complexed with ligands containing amine, sulfur, nitrogen, phosphorus and / or oxygen, or as cyclopentadienyl complexes. Examples of ligands are mercaptans, sulfides, primary, secondary or tertiary amines, primary, secondary or tertiary phosphines, alcohols and ethers as well as cyclopentadiene, benzene, furan, pyrrole, pyridine and thiophene, and also their derivatives, and also complexing agents such as ethanolamines, ethylenediaminetetraacetate , Ethylenediamine triacetate, nitrilotriacetic acid and the like.

The purity of the cerium salts used is not essential according to the invention, it is generally sufficient if the salt is in technical purity, for example of 80% or more, preferably at least 90%, particularly preferably at least at least 95%, very particularly preferably at least 98% and in particular at least 99%. Of course, the salts can also be used in higher or lower purities.

Mixtures of several cerium salts can of course also be used, for example of two or three cerium salts, but the use of a cerium salt is preferred.

The cerium compound is generally present in amounts of up to 2% by weight (based on the total coating composition), preferably up to 1.5, particularly preferably up to 1.0, very particularly preferably up to 0.5 wt .-%.

The cerium compound is usually present in amounts of at least 0.01% by weight, preferably at least 0.05, particularly preferably at least 0.1 and very particularly preferably at least 0.2% by weight.

According to the invention, the cerium compounds are used in dissolved form in the presence of any suitable non-aqueous solvent. Suitable solvents are those in which the cerium compound in question is soluble and which does not lead to any undesirable reactions with the monomer.

Such solvents are, for example, (meth) acrylic acid (ester), acetone, acetylacetone, acetoacetic ester, lower alcohols, such as methanol, ethanol, / so-propanol, n-propanol, n-butanol, / ^' so-butanol, se / c-butanol, terf-butanol, 2-ethylhexyl alcohol, ethylene glycol, diethylene glycol, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol di-n-butyl ether, diethylene glycol, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol glycol 8, with ethylene glycol glycol, polyethylene glycol Polypropylene glycols with a molar mass of 134 to 308, lower carboxylic acids, such as, for example, formic acid, acetic acid or propionic acid, THF, dioxane, acetonitrile, propionitrile, dimethylformamide, dimethyl sulfoxide, sulfolane, dimethyl carbonate, diethyl carbonate, di-n-butyl carbonate, 1, 2- Ethylene carbonate, 1, 2-propylene carbonate or 1,3-propylene carbonate.

Preferred solvents are those in which the cerium compound is soluble to at least 0.5, preferably at least 1, particularly preferably at least 2, very particularly preferably at least 5 and in particular at least 10% by weight and which in turn is in the quantitative ratio used with the coating composition are miscible.

Methanol, ethanol, / ^' so-propanol, n-propanol, n-butanol, ethylene glycol, diethylene glycol, ethylene glycol dimethyl ether, THF, dioxane, acetonitrile, propionitrile, dimethylformamide, dimethyl sulfoxide, sulfolane, dimethyl carbonate, diethyl carbonate, 1, are very particularly preferred. 2-ethylene carbonate and 1, 2-propylene carbonate. Methanol, ethanol, / so-propanol, n-propanol, n-butanol, ethylene glycol, THF, dioxane, acetonitrile, dimethylformamide and dimethyl sulfoxide are particularly preferred.

Radically polymerizable compounds in the coating compositions according to the invention are those compounds which have at least one, for example 1 to 6, preferably 1 to 4 and particularly preferably 1 to 3 groups which are capable of free radical polymerization.

Radically polymerizable groups are, for example, vinyl ether or (meth) acrylate groups, preferably (meth) acrylate groups and particularly preferably acrylate groups.

Compounds which can be polymerized by free radicals are often divided into monofunctional and multifunctional compounds which can be polymerized.

Monofunctional, polymerizable compounds are those with exactly one radical-polymerizable group, multifunctional, polymerizable compounds are those with more than one, preferably with at least two, radical-polymerizable groups.

Monofunctional, polymerizable compounds are, for example, esters of (meth) acrylic acid with alcohols which have 1 to 20 carbon atoms, for example methyl (meth) acrylic acid, (meth) acrylic acid ethyl ester, (meth) acrylic acid butyl ester, (meth) acrylic acid-2 ethylhexyl ester, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, dihydrodicyclopentadienyl acrylate, vinyl aromatic compounds, for example styrene, divinylbenzene, α, β-unsaturated nitriles, for example acrylonitrile, methacrylonitrile , α, β-unsaturated aldehydes, for example acrolein, methacrolein, vinyl esters, for example vinyl acetate, vinyl propionate, halogenated ethylenically unsaturated compounds, for example vinyl chloride, vinylidene chloride, conjugated unsaturated compounds, for example butadiene, isoprene, chloroprene, monounsaturated compounds, for example ethylene, Propylene, 1-butene, 2-butene, isobutene, cyclic monounsaturated compounds, for example cyclopentene, cyclohexene, cyclododecene, N-vinylformamide, allylacetic acid e, vinyl acetic acid, monoethylenically unsaturated carboxylic acids with 3 to 8 carbon atoms and their water-soluble alkali metal, alkaline earth metal or ammonium salts such as: acrylic acid, methacrylic acid, dimethylacrylic acid, ethacrylic acid, maleic acid, citraconic acid, methylene malonic acid, crotonic acid, fumaric acid and itaconic acid, maleic acid, N-vinylpyrrolidone, N-vinyllactams, such as, for example, N-vinylcaprolactam, N-vinyl-N-alkylcarboxamides or N-vinylcarboxamides, such as, for. B. N-vinyl acetamide, N-vinyl-N-methylformamide and N-vinyl-N-methylacetamide or vinyl ether, for example methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, / ^' so-propyl vinyl ether, π-butyl vinyl ether, se-butyl vinyl ether, / so-butyl vinyl ether, terf-butyl vinyl ether, 4-hydroxybutyl vinyl ether, and mixtures thereof.

Preferred among these are the esters of (meth) acrylic acid, particularly preferred are (meth) acrylic acid methyl ester, (meth) acrylic acid ethyl ester, (meth) acrylic acid n-butyl ester, (meth) acrylic acid 2-ethylhexyl ester and 2-hydroxyethyl acrylate (Meth) acrylic acid n-butyl ester, (meth) acrylic acid 2-ethylhexyl ester and 2-hydroxyethyl acrylate and in particular 2-hydroxyethyl acrylate are particularly preferred.

In this document, (meth) acrylic acid stands for methacrylic acid and acrylic acid, preferably for acrylic acid.

Multifunctional, polymerizable compounds in the coating compositions are preferably multifunctional (meth) acrylates which carry more than 1, preferably 2-10, particularly preferably 2-6, very particularly preferably 2-4 and in particular 2-3 (meth) acrylate groups, preferably acrylate groups ,

These can be, for example, esters of (meth) acrylic acid with correspondingly at least dihydric polyalcohols.

Such polyalcohols are, for example, at least divalent polyols, polyether or polyesterols or polyacrylate polyols with an average OH functionality of at least 2, preferably 3 to 10, suitable.

Examples of multifunctional, polymerizable compounds are ethylene glycol diacrylate, 1,2-propanediol diacrylate, 1,3-propanediol diacrylate, 1,4-butanediol diacrylate,

1,3-butanediol diacrylate, 1,5-pentanediol diacrylate, 1,6-hexanediol diacrylate, 1,8-octanediol diacrylate, neopentylglycol diacrylate, 1,1-, 1,2-, 1,3- and 1,4-cyclohexanedimethanol diacrylate , 1, 2-, 1, 3- or 1, 4-cyclohexanediol diacrylate, trimethylolpropane triacrylate, ditrimethylolpropane penta- or hexaacrylate, pentaerythritol tri- or tetraacrylate, glycerol di- or triacrylate, as well as di- and polyacrylates of sugar alcohols, such as, for example, sorbitol , Mannitol, diglycerol, threit, erythritol, adonite (ribitol), arabitol (lyxitol), xylitol, dulcitol (galactitol), maltitol or isomalt, or of polyester polyols, polyetherols, poly-THF with a molecular weight between 162 and 2000, poly -1, 3-propanediol with a molecular weight between 134 and 1178, polyethylene glycol with a molecular weight between 106 and 898, as well as urethane (meth) acrylates or polycarbonate (meth) acrylates.

Further examples are (meth) acrylates of compounds of the formula (Ia) to (Ic),

(la) (Ib) (Ic) wherein

R ¹ and R ² independently of one another are hydrogen or C 1 -C ₈ -alkyl which is optionally substituted by aryl, alkyl, aryloxy, alkyloxy, heteroatoms and / or heterocycles,

k, I, m, q each independently represent an integer from 1 to 10, preferably 1 to 5 and particularly preferably 1 to 3 and

each Xj for i = 1 to k, 1 to I, 1 to m and 1 to q can be selected independently of one another from the group -CH ₂ -CH ₂ -O-, -CH ₂ -CH (CH ₃ ) -O- , -CH (CH ₃ ) -CH ₂ -O-, -CH ₂ - C (CH ₃ ) ₂ -O-, -C (CH ₃ ) ₂ -CH ₂ -O-, -CH ₂ -CHVin-O- , -CHVin-CH ₂ -O-, -CH ₂ -CHPh-O- and -CHPh-CH ₂ -O-, preferably from the group -CH ₂ -CH ₂ -O-, -CH ₂ -CH (CH ₃ ) -O- and -CH (CH ₃ ) -CH ₂ -O-, and particularly preferably -CH ₂ -CH ₂ -O-,

where Ph is phenyl and Vin is vinyl.

In this formula is optionally substituted by aryl, alkyl, aryloxy, alkyloxy, heteroatoms and / or heterocycles C _T - Ciβ alkyl, for example methyl, ethyl, pro- pyl, isopropyl, n-butyl, sec-butyl, tert-butyl, pentyl, Hexyl, heptyl, octyl, 2-ethylhexyl, 2,4,4-trimethylpentyl, decyl, dodecyl, tetradecyl, hetadecyl, octadecyl, 1,1-dimethylpropyl, 1,1-dimethylbutyl, 1,1,3,3- Tetramethylbutyl, preferably methyl, ethyl or n-propyl, very particularly preferably methyl or ethyl.

These are preferably (meth) acrylates of one to twenty times and particularly preferably three to ten times ethoxylated, propoxylated or mixed ethoxylated and propoxylated and in particular exclusively ethoxylated neopentyl glycol, trimethylol propane, trimethylol ethane or pentaerythritol.

Preferred multifunctional, polymerizable compounds are ethylene glycol diacrylate, 1, 2-propanediol diacrylate, 1, 3-propanediol diacrylate, 1, 4-butanediol diacrylate, 1, 6-hexanediol diacrylate, trimethylolpropane triacrylate, pentaerythritol tetra-acrylate, polyate- esterpolyacrylate, poly- esterpolyacrylate, poly- esterpolyacrylate, poly- esterpolyol acrylate, poly- esterpolyol acrylate alkoxylated, particularly preferably ethoxylated trimethylolpropane.

Very particularly preferred multifunctional, polymerizable compounds are 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, trimethylolpropane triacrylate, penta- erythritol tetraacrylate and triacrylate of one to twenty times ethoxylated trimethylolpropane.

Polyester polyols are e.g. from Ulimann's Encyklopadie der Technische Chemie, 4th edition, volume 19, pp. 62 to 65. Polyester polyols are preferably used which are obtained by reacting dihydric alcohols with dihydric carboxylic acids. Instead of the free polycarboxylic acids, the corresponding polycarboxylic anhydrides or corresponding polycarboxylic esters of lower alcohols or their mixtures can also be used to prepare the polyester polyols. The polycarboxylic acids can be aliphatic, cycloaliphatic, araliphatic, aromatic or heterocyclic and optionally, e.g. by halogen atoms, substituted and / or unsaturated. Examples include:

Oxalic acid, maleic acid, fumaric acid, succinic acid, glutaric acid, adipic acid, sebacic acid, dodecanedioic acid, o-phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, azelaic acid, 1, 4-cyclohexanedicarboxylic acid or tetrahydrophthalic acid, korohydride acid, corcidic acid, korkridic acid, corcidic acid, corcidic acid, corcidic acid, corcidic acid, corcidic acid, corcidic acid, corcidic acid, corcidic acid, coric acid hydrophthalic anhydride, tetrachlorophthalic anhydride, endomethylene tetrahydrophthalic anhydride, glutaric anhydride, maleic anhydride, dimeric fatty acids, their isomers and hydrogenation products, and esterifiable derivatives, such as anhydrides or dialkyl esters, for example

preferably methyl, ethyl or n-butyl esters of the acids mentioned are used. Dicarboxylic acids of the general formula HOOC- (CH ₂ ) _y -COOH are preferred, where y is a number from 1 to 20, preferably an even number from 2 to 20, particularly preferably succinic acid, adipic acid, sebacic acid and dodecanedicarboxylic acid.

Suitable polyhydric alcohols for the preparation of the polyesterols are 1,2-propanediol, ethylene glycol, 2,2-dimethyl-1,2-ethanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 3-methylpentane-1,5-diol, 2-ethylhexane-1,3-diol, 2,4-diethyloctane-1,3-diol, 1,6-hexanediol, poly-THF with a molecular weight between 162 and 2000, poly-1, 3-propanediol with a molecular weight between 134 and 1178, poly-1,2-propanediol with a molecular weight between 134 and 898, polyethylene glycol with a molecular weight between 106 and 458, neopentyl glycol, hydroxypivalic acid neopentyl glycol cholesterol, 2-ethyl-1,3-propanediol, 2-methyl-1,3-propanediol, 2,2-bis (4-hydroxycyclohexyl) propane, 1,1-, 1,2-, 1,3- and 1 , 4-cyclohexanedimethanol, 1,2-, 1,3- or 1,4-cyclohexanediol, trimethylolbutane, trimethylolpropane, trimethylolethane, neopentylglycol, pentaerythritol, glycerol, ditrimethylolpropane, dipentaerythritol, sorbitol, mannitol, diglycerol, threitol, erythritol (Ribit), Arabit (Lyxit), Xylit, Dulcit (Galactit), Maltitol or isomalt, which can optionally be alkoxylated as described above.

Alcohols of the general formula HO- (CH ₂ ) χ-OH are preferred, where x is a number from 1 to 20, preferably an even number from 2 to 20. Ethylene glycol are preferred. col, butane-1, 4-diol, hexane-1, 6-diol, octane-1, 8-diol and dodecane-1,12-diol. Neopentyl glycol is also preferred.

Also suitable are polycarbonate diols, as can be obtained, for example, by reacting phosgene with an excess of the low molecular weight alcohols mentioned as structural components for the polyester polyols. Lactone-based polyester diols are also suitable, these being homopolymers or copolymers of lactones, preferably addition products of lactones with terminal hydroxyl groups onto suitable difunctional starter molecules. Suitable lactones are preferably those which are derived from compounds of the general formula HO- (CH ₂ ) _z -COOH, where z is a number from 1 to 20 and an H atom of a methylene unit also by a Cr to C ₄ - Alkyl radical can be substituted. Examples are ε-caprolactone, ß-propiolactone, gamma-butyrolactone and / or methyl-ε-caprolactone, 4-hydroxybenzoic acid, 6-hydroxy-2-naphthalic acid or pivalolactone and mixtures thereof. Suitable starter components are, for example, the low molecular weight dihydric alcohols mentioned above as the structural component for the polyester polyols. The corresponding polymers of ε-caprolactone are particularly preferred. Lower polyester diols or polyether diols can also be used as starters for the preparation of the lactone polymers. Instead of the polymers of lactones, the corresponding chemically equivalent polycondensates of the hydroxycarboxylic acids corresponding to the lactones can also be used.

Furthermore, the multifunctional, polymerizable compound can be urethane (meth) acrylates, epoxy (meth) acrylates or carbonate (meth) acrylates.

Urethane (meth) acrylates are e.g. obtainable by reacting polyisocyanates with hydroxyalkyl (meth) acrylates or vinyl ethers and optionally chain extenders such as diols, polyols, diamines, polyamines or dithiols or polythiols. Urethane (meth) acrylates which are dispersible in water without the addition of emulsifiers additionally contain ionic and / or nonionic hydrophilic groups, which e.g. can be introduced into the urethane by structural components such as hydroxycarboxylic acids.

The usable polyurethanes essentially contain as structural components:

(a) at least one organic aliphatic, aromatic or cycloaliphatic di- or polyisocyanate,

(b) at least one compound having at least one isocyanate-reactive group and at least one free-radically polymerizable unsaturated group and (c) optionally at least one compound with at least two isocyanate-reactive groups.

Component (a) includes, for example, aliphatic, aromatic and cycloaliphatic di- and polyisocyanates with an NCO functionality of at least 1.8, preferably 1, 8 to 5 and particularly preferably 2 to 4, and their isocyanurates, biurets , Allophanate and Uretdione.

The diisocyanates are preferably isocyanates with 4 to 20 carbon atoms. Examples of customary diisocyanates are aliphatic diisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate (1,6-diisocyanatohexane), octamethylene diisocyanate, decamethylene diisocyanate, dodecamethylene diisocyanate, tetradecamethylene diisocyanate, derivatives of lysethylene diamine diisocyanate, derivatives of tisyl diamine diamine 4-, 1, 3- or 1, 2-diisocyanatocyclohexane, 4,4'- or 2,4'-di (isocyanatocyclohexyl) methane, 1-isocyanato-3,3,5-trimethyl-5- (isocyanatomethyl) cyclohexane (isophorone diisocyanate), 1,3- or 1,4-bis (isocyanatomethyl) cyclohexane or 2,4- or 2,6-diisocyanato-1-methylcyclohexane as well as aromatic diisocyanates such as 2,4- or 2,6- Toluene diisocyanate and its isomer mixtures, m- or p-xylylene diisocyanate, 2,4'- or 4,4'-diisocyanatodiphenylmethane and their isomer mixtures, 1,3- or 1,4-phenylene diisocyanate, 1-chloro-2,4-phenylene diisocyanate, 1 , 5-naphthylene diisocyanate, di phenylene-4,4'-diisocyanate, 4,4'-diisocyanato-3,3'-dimethyldiphenyl, 3-methyldiphenylmethane-4,4'-diisocyanate, tetramethylxylylene diisocyanate, 1,4-diisocyanatobenzene or diphenyl ether-4,4 ' diisocyanate.

Mixtures of the diisocyanates mentioned can also be present.

Hexamethylene diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane, isophorone diisocyanate and di (isocyanatocyclohexyl) methane are preferred.

Suitable polyisocyanates are polyisocyanates containing isocyanurate groups, uretdione diisocyanates, polyisocyanates containing biuret groups, polyisocyanates containing urethane or allophanate groups, polyisocyanates containing oxadiazinetrione groups, uretonimine-modified polyisocyanates of straight-chain or branched C ₂ -C 6 -alkylene diisocyanates with cyclo-diisocyanates 20 carbon atoms or aromatic diisocyanates with a total of 8 to 20 carbon atoms or mixtures thereof.

The di- and polyisocyanates that can be used preferably have a content of isocyanate groups (calculated as NCO, molecular weight = 42) of 10 to 60% by weight, based on the di- and polyisocyanate (mixture), preferably 15 to 60% by weight. and particularly preferably 20 to 55% by weight. Preferred are aliphatic or cycloaliphatic di- and polyisocyanates, for example the aliphatic or cycloaliphatic diisocyanates mentioned above, or mixtures thereof.

Are also preferred

1) Isocyanurate group-containing polyisocyanates of aromatic, aliphatic and / or cycloaliphatic diisocyanates. The corresponding aliphatic and / or cycloaliphatic isocyanato-isocyanurates and in particular those based on hexamethylene diisocyanate and isophorone diisocyanate are particularly preferred. The isocyanurates present here are, in particular, tris-isocyanatoalkyl or tris-isocyanatocycloalkyl isocyanurates, which are cydic trimers of the diisocyanates, or mixtures with their higher homologues having more than one isocyanurate ring. The isocyanato-isocyanurates generally have an NCO content of 10 to 30% by weight, in particular 15 to 25% by weight, and an average NCO functionality of 3 to 4.5.

2) Uretdione diisocyanates with aromatic, aliphatic and / or cycloaliphatic isocyanate groups, preferably aliphatic and / or cycloaliphatic bound and in particular those derived from hexamethylene diisocyanate or isophorone diisocyanate. Uretdione diisocyanates are cydic dimerization products of diisocyanates. The uretdione diisocyanates can be used in the preparations as the sole component or in a mixture with other polyisocyanates, in particular those mentioned under 1).

3) Polyisocyanates containing biuret groups with aromatic, cycloaliphatic or aliphatic, preferably cycloaliphatic or aliphatic, isocyanate groups, in particular tris (6-isocyanatohexyl) biuret or mixtures thereof with its higher homologues. These polyisocyanates containing biuret groups generally have an NCO content of 18 to 22% by weight and an average NCO functionality of 3 to 4.5.

4) Polyisocyanates containing urethane and / or allophanate groups with aromatically, aliphatically or cycloaliphatically bound, preferably aliphatically or cycloaliphatically bound, isocyanate groups, such as, for example, by reacting excess amounts of hexamethylene diisocyanate or of isophorone diisocyanate with polyhydric alcohols such as 1-trimethylol propylene, pentopentyl eryl glycol, for example trimethylol propylene, pentophenyl eryl glycol, pentopentyl eryl glycol, for example trimethylol propylene , 4-butanediol, 1, 6-hexanediol, 1, 3-propanediol, ethylene glycol, diethylene glycol, glycerol, 1, 2-dihydroxypropane or mixtures thereof see can be obtained. These polyisocyanates containing urethane and / or allophanate groups generally have an NCO content of 12 to 20% by weight and an average NCO functionality of 2.5 to 3.

5) Polyisocyanates containing oxadiazinetrione groups, preferably derived from hexamethylene diisocyanate or isophorone diisocyanate. Such polyisocyanates containing oxadiazinetrione groups can be prepared from diisocyanate and carbon dioxide.

6) Uretonimine-modified polyisocyanates.

The polyisocyanates 1) to 6) can be used in a mixture, if appropriate also in a mixture with diisocyanates.

Component (b) may be a compound which has at least one group which is reactive toward isocyanate and at least one group which can be polymerized by free radicals.

Groups reactive toward isocyanate can be, for example, -OH, -SH, -NH ₂ and -NHR ³ , where R ^{3 is} hydrogen or an alkyl group containing 1 to 4 carbon atoms, such as methyl, ethyl, n-propyl, / so-propyl, n -Butyl, / so-butyl, se / -Butyl or tert-butyl.

Components (b) can be, for example, monoesters of α, β-unsaturated carboxylic acids, such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, fumaric acid, maleic acid, acrylamidoglycolic acid, methacrylamidoglycolic acid or vinyl ethers with di- or polyols, which are preferably 2 to 20 carbon atoms and have at least two hydroxyl groups, such as ethylene glycol, diethylene glycol, triethylene glycol, 1, 2-propylene glycol, 1, 3-propylene glycol, 1,1-dimethyl-1,2-ethanediol, dipropylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol, tripropylene glycol, 1, 4-butanediol, 1,5-pentanediol, neopentyl glycol, 1, 6-hexanediol, 2-methyl-1,5-pentanediol, 2-ethyl-1,4-butanediol, 1,4-dimethylolcyclohexane, 2,2- Bis (4-hydroxycyclohexyl) propane, glycerol, trimethylolethane, trimethylolpropane, trimethylolbutane, pentaerythritol, ditrimethylolpropane, erythritol, sorbitol, poly-THF with a molecular weight between 162 and 2000, poly-1,3-propanediol with a molecular weight between 134 and 400 or polyethylene glycol m it with a molecular weight between 238 and 458. Furthermore, esters or amides of (meth) acrylic acid with amino alcohols, for. B. 2-aminoethanol, 2- (methylamino) ethanol, 3-amino-1-propanol, 1-amino-2-propanol or 2- (2-aminoethoxy) ethanol, 2-mercaptoethanol or polyaminoalkanes, such as ethylenediamine or diethylene triamine, or vinyl acetic acid. Unsaturated polyether or polyesterols or polyacrylate polyols with an average OH functionality of 2 to 10 are also suitable.

Examples of amides of ethylenically unsaturated carboxylic acids with amino alcohols are hydroxyalkyl (meth) acrylamides such as N-hydroxymethylacrylamide,

N-hydroxymethyl methacrylamide, N-hydroxyethyl acrylamide, N-hydroxyethyl methacrylamide, 5-hydroxy-3-oxapentyl (meth) acrylamide, N-hydroxyalkyl crotonamides such as N-hydroxymethyl crotonamide or N-hydroxyalkyl maleimides such as N-hydroxyethyl maleimide.

2-Hydroxyethyl (meth) acrylate, 2- or 3-hydroxypropyl (meth) acrylate, 1,4-butanediol mono (meth) acrylate, neopentyl glycol mono (meth) acrylate, 1,5-pentanediol mono (meth) acrylate, 1 are preferably used , 6-hexanediol mono (meth) acrylate, glycerol mono- and di (meth) acrylate, trimethylolpropane mono- and di (meth) acrylate, pentaerythritol mono-, di- and tri (meth) acrylate as well as 4-hydroxybutyl vinyl ether, 2-aminoethyl (meth ) acrylate, 2-aminopropyl (meth) acrylate, 3-aminopropyl (meth) acrylate, 4-aminobutyl (meth) acrylate, 6-aminohexyl (meth) acrylate, 2-thioethyl (meth) acrylate, 2-aminoethyl (meth) acrylamide , 2-aminopropyl (meth) acrylamide, 3-aminopropyl (meth) acrylamide, 2-hydroxyethyl (meth) acrylamide, 2-hydroxypropyl (meth) acrylamide or 3-hydroxypropyl (meth) acrylamide. 2-Hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2- or 3-hydroxypropyl acrylate, 1, 4-butanedioimonoacrylate and 3- (acryloyloxy) -2-hydroxypropyl methacrylate are particularly preferred.

Component (c) is a compound which contains at least two groups which are reactive toward isocyanate, for example -OH, -SH, -NH ₂ or -NHR ⁴ , in which R ⁴ is, independently of one another, hydrogen, methyl, ethyl, / ^' so Propyl, n-propyl, n-butyl, / so-butyl, se / c-butyl or terf-butyl may have.

These are preferably diols or polyols, such as hydrocarbon diols having 2 to 20 carbon atoms, for example ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,1-dimethylethane-1,2-diol, 1,6-hexanediol, 1,10-decanediol, bis (4-hydroxycyclohexane) isopropylidene, tetramethylcyclobutanediol, 1,2-, 1,3- or 1,4-cyclohexanediol, cyclooctanediol, norbornanediol, pinanediol, decalinediol, etc., their esters with short-chain dicarboxylic acids, such as adipic acid, cyclohexanedicarboxylic acid, their carbonates, prepared by reacting the diols with phosgene or by transesterification with dialkyl or diaryl carbonates, or aliphatic diamines, such as methylene and isopropylidene bis (cyclohexylamine), Piperazine, 1,2-, 1,3- or 1,4-diaminocyclohexane, 1,2-, 1,3- or 1,4-cyclohexane-bis- (methylamine), etc., dithiols or polyfunctional alcohols, secondary or primary amino alcohols, such as ethanolamine, diethanolamine, monopropanolamine, dipropanolamine etc. or thioalcohols, such as thioethylene glycol. Diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, neopentyl glycol, pentaerythritol, 1,2- and 1,4-butanediol, 1,5-pentanediol, 2-methyl-1,5-pentanediol, 2-ethyl- 1,4-butanediol, 1,2-, 1,3- and 1,4-dimethylolcyclohexane, 2,2-bis (4-hydroxycyclohexyl) propane, glycerin, trimethylolethane, trimethylolpropane, trimethylolbutane, dipentaerythritol, ditrimethylolpropane, erythritol and sorbitol, 2-aminoethanol, 3-amino-1-propanol, 1-amino-2-propanol or 2- (2-aminoethoxy) ethanol, bisphenol A, or butanetriol.

Unsaturated polyether or polyesterols or polyacrylate polyols with an average OH functionality of 2 to 10 are also suitable, as are polyamines, e.g. Polyethyleneimine or free amine group containing polymers of e.g. Poly-N-vinyl formamide.

The cycloaliphatic diols, such as e.g. Bis (4-hydroxycyclohexane) isopropylidene, tetramethylcyclobutanediol, 1,2-, 1,3- or 1,4-cyclohexanediol, cyclooctanediol or norbornanediol.

The polyurethanes that can be used are obtained by reacting components (a), (b) and (c) with one another.

The molar composition (a) :( b) :( c) per 3 mol of reactive isocyanate groups in

(a) can generally be chosen as desired, preferably as follows:

(b) 1.5-3.0, preferably 2.0-2.9, particularly preferably 2.0-2.5 and in particular 2.0-2.3 mol of isocyanate-reactive groups and

(c) 0-1.5, preferably 0.1-1.0, particularly preferably 0.5-1.0 and in particular 0.7-1.0 mol of groups reactive toward isocyanate.

When the polyurethanes are used in aqueous systems, essentially all of the isocyanate groups present have preferably reacted.

The formation of the adduct from the compound containing isocyanate groups and the compound which contains groups reactive toward isocyanate groups is generally carried out by mixing the components in any order, if appropriate at elevated temperature. The compound which contains groups which are reactive toward isocyanate groups is preferably added to the compound containing isocyanate groups, preferably in several steps. The compound containing isocyanate groups is particularly preferably introduced and the compounds which contain groups reactive toward isocyanate are added. In particular, the isocyanate group-containing compound (a) is initially introduced and then (b) is added. If desired, further desired components can subsequently be added.

As a rule, the reaction is carried out at temperatures between 5 and 100 ° C., preferably between 20 to 90 ° C. and particularly preferably between 40 and 80 ° C. and in particular between 60 and 80 ° C.

It is preferred to work under anhydrous conditions. Anhydrous means that the water content in the reaction system is not more than 5% by weight, preferably not more than 3% by weight and particularly preferably not more than 1% by weight.

The reaction can be carried out in the presence of at least one suitable inert gas, e.g. Nitrogen, argon, helium, carbon dioxide or the like, but this is usually not necessary.

The reaction can also be carried out in the presence of an inert solvent, e.g. Acetone, / so-butyl methyl ketone, toluene, xylene, butyl acetate or ethoxyethyl acetate.

The urethane (meth) acrylates preferably have a number average molecular weight M _n of 500 to 20,000, in particular from 500 to 10,000, particularly preferably 600 to 3000 g / mol (determined by gel permeation chromatography with tetrahydrofuran and polystyrene as standard).

The urethane (meth) acrylates preferably have a content of 1 to 5, particularly preferably 2 to 4, moles of (meth) acrylic groups per 1000 g of urethane (meth) acrylate.

Epoxy (meth) acrylates can be obtained by reacting epoxides with (meth) acrylic acid. Examples of suitable epoxides are epoxidized olefins, aromatic glycidyl ethers or aliphatic glycidyl ethers, preferably those of aromatic or aliphatic glycidyl ethers.

Epoxidized olefins can, for example, be ethylene oxide, propylene oxide, / so-butylene oxide, 1-butene oxide, 2-butene oxide, vinyl oxirane, styrene oxide or epichlorohydrin, ethylene oxide, propylene oxide, / ^' so-butylene oxide, vinyl oxirane, styrene oxide or epichlorohydrin are particularly preferred Ethylene oxide, propylene oxide or epichlorohydrin and very particularly preferably ethylene oxide and epichlorohydrin. Aromatic glycidyl ethers are, for example, bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol B diglycidyl ether, bisphenol S diglycidyl ether, hydroquinone diglycidyl ether, alkylation products of phenol / dicyclopentadiene, for example 2,5-bis [(2 3-EPoxypropoxy) phenyl] octahydro-4,7-methano-5H-indene) (CAS No. [13446-85-0]), Tris [4- (2,3-epoxypropoxy) phenyl] methane isomers) CAS-No. [66072-39-7]), phenol based epoxy novolaks (CAS No. [9003-35-4]) and cresol based epoxy novolaks (CAS No. [37382-79-9]).

Examples of aliphatic glycidyl ethers are 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, pentaerythritol tetraglycidyl ether, 1,1,2,2-tetrakis [4- (2,3-epoxypropoxy) phenyl] ethane (CAS No. [ 27043-37-4]), diglycidyl ether of polypropylene glycol (α, ω-bis (2,3-epoxypropoxy) poly (oxypropylene) (CAS No. [16096-30-3]) and of hydrogenated bisphenol A (2nd , 2-bis [4- (2,3-epoxypropoxy) cyclohexyl] propane, CAS No. [13410-58-7]).

The epoxy (meth) acrylates and vinyl ethers preferably have a number average molecular weight M _{n of} from 200 to 20,000, particularly preferably from 200 to 10,000 g / mol and very particularly preferably from 250 to 3000 g / mol; the content of (meth) acrylic or vinyl ether groups is preferably 1 to 5, particularly preferably 2 to 4, per 1000 g of epoxy (meth) acrylate or vinyl ether epoxide (determined by gel permeation chromatography using polystyrene as standard and tetrahydrofuran as eluent).

Carbonate (meth) acrylates contain on average preferably 1 to 5, in particular 2 to 4, particularly preferably 2 to 3 (meth) acrylic groups and very particularly preferably 2 (meth) acrylic groups.

The number average molecular weight M _{n of} the carbonate (meth) acrylates is preferably less than 3000 g / mol, particularly preferably less than 1500 g / mol, particularly preferably less than 800 g / mol (determined by gel permeation chromatography with polystyrene as standard, solvent tetrahydrofuran).

The carbonate (meth) acrylates can be obtained in a simple manner by transesterification of carbonic acid esters with polyhydric, preferably dihydric alcohols (diols, for example hexanediol) and subsequent esterification of the free OH groups with (meth) acrylic acid or transesterification with (meth) acrylic acid esters, like it for example is described in EP-A 92269. They are also available by converting phosgene, urea derivatives with polyvalent, e.g. dihydric alcohols.

Analogously, vinyl ether carbonates can also be obtained by reacting a hydroxyalkyl vinyl ether with carbonic acid esters and, if appropriate, dihydric alcohols. Also conceivable are (meth) acrylates or vinyl ethers of polycarbonate polyols, such as the reaction product of one of the di- or polyols mentioned and a carbonic acid ester and a hydroxyl-containing (meth) acrylate or vinyl ether.

Suitable carbonic acid esters are e.g. Ethylene, 1,2- or 1,3-propylene carbonate, carbonic acid dimethyl, diethyl or dibutyl ester.

Suitable hydroxy group-containing (meth) acrylates are, for example, 2-hydroxyethyl (meth) acrylate, 2- or 3-hydroxypropyl (meth) acrylate, 1,4-butanediol mono (meth) acrylate, neopentyl glycol mono (meth) acrylate, glycerol mono- and di (meth ) acrylate, trimethylol propane mono- and di (meth) acrylate and pentaerythritol mono-, di and tri (meth) acrylate.

Suitable hydroxy group-containing vinyl ethers are e.g. 2-hydroxyethyl vinyl ether and 4-hydroxybutyl vinyl ether.

Particularly preferred carbonate (meth) acrylates are those of the formula:

wherein R is H or CH ₃ , X is a C _∑ -C ^ alkylene group and n is an integer from 1 to 5, preferably 1 to 3.

R is preferably H and X is preferably C ₂ -C 10 -alkylene, for example 1,2-ethylene, 1,2-propylene, 1,3-propylene, 1,4-butylene or 1,6-hexylene, particularly preferred for C - to C ₈ alkylene. X very particularly preferably represents Cβ-alkylene.

The carbonate (meth) acrylates are preferably aliphatic carbonate (meth) acrylates.

Among the multifunctional, polymerizable compound, urethane (meth) acrylates are particularly preferred.

In a preferred embodiment of the present invention, the coating composition contains at least one pigment.

Other typical coatings additives include, for example, antioxidants, stabilizers, activators (accelerators), fillers, pigments, dyes, antistatic agents, Flame retardants, thickeners, thixotropic agents, surface-active agents, viscosity modifiers, plasticizers or chelating agents are used.

If a pigment containing cerium is used, it does not act as a significant cerium source in the sense of this invention due to its low solubility which characterizes pigments. The solubility of pigments is usually not more than 1 g / 1000 g of application medium at 25 ° C.

As accelerators for thermal post-curing, e.g. Tin octoate, zinc octoate, dibutyltin laurate or diaza [2.2.2] bicyclooctane can be used.

Furthermore, in addition to the cerium compound functioning as an initiator, one or more thermally activatable initiators can be added, e.g. Potassium peroxodisulfate, dibenzoyl peroxide, cyclohexanone peroxide, di-tert-butyiperoxide, azobis / so-butyro-nitrile, cyclohexylsulfonylacetyl peroxide, di- / so-propyl percarbonate, ferf-butyl peroctoate or benzpinacol, and for example such a thermally activatable initiator Have 80 ° C of more than 100 hours, such as di-t-butyl peroxide, cumene hydroperoxide, dicumyiperoxide, t-butyl perbenzoate, silylated pinacoles, the z. B. are commercially available under the trade name ADDID 600 from Wacker or amine N-oxides containing hydroxyl groups, such as 2,2,6,6-tetramethylpiperidine-N-oxyl, 4-hydroxy-2,2,6,6- Tetramethylpiperidine-N-oxyl etc.

Further examples of suitable initiators are described in "Polymer Handbook", 2nd edition, Wiley & Sons, New York.

In addition to radical (co) polymerized (co) polymers, conventional organic and inorganic thickeners such as hydroxymethyl cellulose or bentonite are suitable as thickeners.

As chelating agents e.g. Ethylenediamine acetic acid and its salts as well as β-di-ketones are used.

Suitable fillers include silicates, e.g. B. by hydrolysis of silicon tetrachloride available silicates such as Aerosil ^® from Degussa, silica, talc, aluminum silicates, magnesium silicates, calcium carbonates etc.

Suitable stabilizers include typical UV absorbers such as oxanilides, triazines and benzotriazole (the latter available as Tinuvin ^® brands from Ciba specialty chemistry) and benzophenones. These can be used alone or together with suitable radical scavengers, for example sterically hindered amines such as 2,2,6,6-tetramethylpiperidine, 2,6-di-tert-butylpiperidine or their derivatives, e.g. B. bis- (2,2,6,6-tetra-methyl-4-piperidyQsebacinate) can be used. Stabilizers are usually used in quantities from 0.1 to 5.0% by weight, based on the solid components contained in the preparation.

The composition of the coating compositions is usually as follows:

Proportion of the at least one cerium (IV) compound as indicated above,

The proportion of the solvent can be up to 25% by weight, up to 20, up to 15 and very particularly preferably up to 12% by weight. The lower limit is determined by the minimum amount required to dissolve the at least one cerium (IV) compound in the coating composition. This can be worked out by simple solubility tests. The amount of solvent is preferably kept as low as possible.

"The proportion of the at least one compound capable of free radical polymerization can make up the entire rest of the coating composition apart from cerium (IV) compound and any solvent present. For example, the proportion can be up to 99.9% by weight, preferably up to 98%, particularly preferably up to 95, very particularly preferably up to 90% by weight and in particular up to 85% by weight The proportion of the at least one radical-polymerizable compound is at least 25% by weight, preferably at least 50, particularly preferably at least 65 and very particularly preferably at least 75% by weight.

~ Furthermore, up to 50% by weight, preferably 1 to 50, particularly preferably 5 to 30 and very particularly preferably 20 to 30% by weight of further paint-typical additives can be present.

The requirement here is that the sum of all components is 100% by weight.

The coating compositions of the invention can advantageously be used in thermal curing, ie in the radical polymerization of monomers, which is triggered by an increase in the temperature above a certain critical temperature. This critical temperature may for example be above 40 ° C, preferably from above 60 ^β C, more preferably between 60 and 220 ° C, very particularly preferably between 80 and 180 ° C and in particular between 80 and 160 ° C.

In addition to thermal curing, other curing mechanisms can also be involved, for example radiation, moisture, chemical and / or oxidative curing. It is an advantage of the present invention that the presence of the cerium compound with simultaneous radiation curing means that the coating composition is thermally cured even in shadow areas and that curing can be triggered thermally in pigmented coating compositions.

Another object of the present invention is a method for starting a radical polymerization and a method for curing coating compositions, in which the coating composition to be cured contains at least one cerium (IV) compound and the coating composition is brought to a temperature at which the at least a cerium (IV) compound triggers a radical polymerization.

If polymerization inhibitors are present in the coating composition, these are deactivated in a preferred embodiment of the invention. This can be done, for example, by carrying out the curing in the absence of oxygen, for example under an inert gas, in the case of aerobic polymerization inhibitors, that is to say those which require the presence of oxygen to inhibit radical polymerizations. It can also be useful to remove traces of oxygen from the coating mass by flushing the coating mass with an inert gas. In the presence of aerobic polymerization inhibitors in the coating composition, the inhibition can generally be eliminated by keeping the coating composition at the temperature required to initiate the polymerization longer and / or by increasing the amount of cerium (IV) compounds.

In a preferred embodiment of the invention, the radical polymerization is carried out in the absence of polymerization inhibitors and co-stabilizers.

In a further embodiment of the invention, the thermal initiation of radical polymerization is carried out in the absence of other thermal polymerization initiators.

The coating compositions containing the mixtures according to the invention can be sprayed using a wide variety of methods, e.g. Air pressure, airless or electrostatic spraying processes using one- or two-component spraying systems, but also by spraying, filling, knife coating, brushing, rolling, rolling, pouring, laminating, back-spraying or coextruding.

The coatings are generally dried and cured under normal temperature conditions, ie without the coating being heated. However, the mixtures according to the invention can also be used for the production of coatings which, after application at elevated temperature, for example at 40-250 ° C., preferably 40 - 150 ° C and especially at 40 to 100 ° C dried and cured.

The coating compositions according to the invention and lacquer formulations containing them are particularly suitable for coating substrates such as wood, paper, textile, leather, fleece, plastic surfaces, glass, ceramics, mineral building materials, such as shaped cement blocks and fiber cement boards, or metals or coated metals , preferably of plastics or metals.

The coating compositions of the invention are particularly preferably suitable as or in exterior coatings, that is to say those applications which are exposed to daylight, preferably of buildings or parts of buildings, interior coatings, road markings, coatings on vehicles and aircraft. In particular, the coating compositions according to the invention are used as or in automotive clearcoats and topcoats.

The coating compositions containing the mixtures according to the invention can be used in particular as primers, fillers, pigmented topcoats and clearcoats in the field of car repair or large vehicle painting. The coating compositions are particularly suitable for applications in which particularly high application security, weather resistance, optics, resistance to solvents, chemicals and water are required, such as in automotive repair and large vehicle painting.

The following examples are intended to illustrate the properties of the invention, but without restricting it.

Examples

Unless otherwise stated, "parts" or "%" in this document are understood to mean "parts by weight" or "weight%".

The pendulum hardness was determined according to DIN 53157 and is a measure of the hardness of the coating. The specification is made in seconds (s). High values mean high hardness. Example 1 :

A formulation was prepared consisting of

71% by weight Laromer® LR 8987 from BASF Aktiengesellschaft (aliphatic urethane acrylate in 1,6-hexanediol diacrylate) 18% by weight hydroxyethyl acrylate

11% by weight ethanol

0.6 wt% Ce (NH ₄ ) ₂ (NO ₃ ) β

This formulation was applied to a glass plate using a 100 μm spiral doctor blade and cured at 120 ° C.

The thermal hardening of the paint film already occurred after 15 minutes, so that a pendulum hardness of 50 s was achieved. Continued curing was observed with further heating, so that after 20 min an exceptionally hard film with an extremely high pendulum hardness of 288 s was obtained.

Comparative Example:

The formulation from Example 1 but without the cerium compound was applied and cured as described in Example 1.

The coating composition remained liquid even after 20 minutes of curing.

Claims

claims

1. Coating compositions containing ^~ at least one cerium (IV) compound, if appropriate at least one non-aqueous solvent, at least one compound capable of free radical polymerization and if appropriate further additives typical of lacquer.

2. Coating compositions according to claim 1, characterized in that the cerium (IV) compound is selected from the group consisting of ammonium hexanitratocerate (IV) (cerium (IV) ammonium nitrate, (NH) ₂ [Ce (NO ₃ ) ₆ ] ), Sodium hexanitratocerate (IV) (Na ₂ [Ce (NO ₃ ) ₆ ]), potassium hexanitratocerate (IV) (K ₂ [Ce (NO ₃ ) _β ]), cerium (IV) ammonium sulfate (Ce (NH ₄ ) ₂ (NO ₃ ) ₆ )), cerium (IV) hydroxide, cerium (IV) isopropylate-isopropanol complex, cerium (IV) oxide (CeO ₂ ) and cerium (IV) sulfate (Ce (SO ₄ ) ₂ ).

3. Coating compositions according to claim 1, characterized in that the cerium (IV) compound in the coating composition is obtained by oxidation of cerium compounds of a lower oxidation state.

4. Coating compositions according to claim 3, characterized in that cerium (III) compounds are used as cerium compounds of a lower oxidation level.

5. Coating compositions according to claim 4, characterized in that the cerium (III) compound is selected from the group consisting of cerium (III) acetate, cerium (III) acetate hydrate, cerium (III) acetylacetonate, cerium (III) acetylacetonate hydrate , Cerium (III) bromide, cerium (III) carbonate, cerium (III) carbonate hydrate, cerium (III) chloride, cerium (III) chloride heptahydrate, cerium (III) ethylhexanoate and its solutions or dispersions in mineral oil or naphtha, cerium (III) fluoride, cerium (III) nitrate, cerium (III) nitrate hexahydrate, cerium (III) oxalate, cerium (III) sulfate, cerium (III) sulfate octahydrate, cerium (III) oxide and cerium (III) acrylate.

6. coating compositions according to claim 1, characterized in that the solvent is selected from the group consisting of methanol, ethanol, / so-propanol, n-propanol, n-butanol, / so-butanol, sβ-butanol, terf-butanol, 2-Ethylhexyl alcohol, ethylene glycol, diethylene glycol, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol di-n-butyl ether, diethylene glycol, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol di-n-butyl ether with a polyethylene glycol 134, polyethylene glycol glycol to a mixture of polyethylene glycol and polyethylene glycol to 308, lower carboxylic acids, such as formic acid, acetic acid or propionic acid, THF, dioxane, acetonitrile, propionitrile, dimethyl formamide, dimethyl sulfoxide, sulfolane, dimethyl carbonate, diethyl carbonate, di-n-butyl carbonate, 1,2-ethylene carbonate, 1,2-propylene carbonate and 1,3-propylene carbonate.

7. coating compositions according to any one of the preceding claims, containing at least one free-radically polymerizable monomer selected from the group consisting of esters of (meth) acrylic acid with alcohols which have 1 to 20 carbon atoms, vinyl aromatic compounds, α, β-unsaturated nitriles, α, β-unsaturated aldehydes, vinyl esters, halogenated ethylenically unsaturated compounds, conjugated unsaturated compounds, monounsaturated compounds, cyclic monounsaturated compounds, N-vinylformamide, allyl acetic acid, vinyl acetic acid, monoethylenically unsaturated carboxylic acids with 3 to 8 carbon atoms and their water-soluble alkali metal, alkaline earth metal or ammonium salts, N-vinyl pyrrolidone, N-vinyl lactams, N-vinyl-N-alkyl carboxamides, N-vinyl carboxamides and vinyl ethers.

8. Coating compositions according to one of the preceding claims, containing at least one multifunctional, polymerizable compound selected from the group consisting of esters of (meth) acrylic acid with at least dihydric polyalcohols, which can optionally be alkoxylated, urethane (meth) acrylates, epoxy (meth ) acrylates and carbonate (meth) acrylates.

9. Coating compositions according to one of the preceding claims, characterized in that the water content is 10% by weight or less.

10. A method for coating substrates, characterized in that a substrate is coated with a coating composition according to one of the preceding claims.

11. A method for starting a radical polymerization, characterized in that the coating composition to be cured contains at least one cerium (IV) compound and the coating composition is brought to a temperature at which the at least one cerium (IV) compound triggers a radical polymerization ,

12. Use of Ce (IV) compounds to start a radical polymerization.