WO2008148739A1 - Method for the production of water-emulsifiable polyurethane acrylates - Google Patents

Abstract

The present invention relates to a method for the production of water-emulsifiable polyurethane acrylates and the use thereof.

Description

 Process for the preparation of water-emulsifiable polyurethane acrylates

description

The present invention describes a process for the preparation of water-emulsifiable polyurethane acrylates and their use.

The urethane (meth) acrylates which can be prepared according to the invention are those which comprise at least one polyalkylene glycol and which can therefore be dispersed or diluted in water. Processes for the preparation of water-soluble, dilutable, or emulsifiable, radiation-curable urethane (meth) acrylates are known. The hydrophilicity of such urethane (meth) acrylates is based on the water solubility of the polyethylene glycol or polypropylene glycol chain. In this way, the urethane (meth) acrylate becomes water-soluble. In addition, water solubility can be increased by copolymerizing monomers, each having acid or base functions, to form an internal salt which provides increased water solubility.

Water-dispersible urethane acrylates are already known from e.g. EP-A 98 752 or DE-OS 2 936 039. The hydrophilicity of these known systems is based on the presence of ionic centers, in particular of carboxylate or sulfonate groups, which have alkali ions or ammonium ions as counterions. The added for neutralization compounds can cause yellowing of the paints.

Thus, there is a need for further urethane (meth) acrylates in which neutralization is achieved without yellowing.

Frequently, auxiliary solvents are used for better solubilization, which are liberated during the drying process and can thus lead to an environmental impact. What is desired is a low so-called. VOC value (volatile organic compounds), which can be achieved for example by replacing organic solvents with water.

Another possibility for obtaining water-dilutable products is the use of external emulsifiers. Thus, for example, according to US Pat. No. 4,070,323, polyurethanes carrying acryloyl groups are dispersed in water with the aid of anionic or cationic oil-in-water emulsifiers (for example sodium lauryl sulfate). These emulsifiers are not incorporated in the paint film in a radical crosslinking. As a result, the degree of attainable water resistance of the paint films is thus disadvantageously lowered. The water-soluble urethane (meth) acrylates according to the invention are (meth) acryloyl groups and alkylene oxide units incorporated within polyether chains, and polyurethanes preferably having inner salt groups, which are prepared by a specific process. Such hydrophilic polyurethanes are, for example, from Polymer Science USSR, Vol. 15, No. 4, May 1974, pages 81-822, EP-AO 168 173, EP-AO 154 237, EP-AO 021 824 or EP-AO 381 862 and from Journal of Applied Polymer Science, Vol. 84, 1818-1831 (2002).

According to DE-A-3,437,918, aqueous oligourethane dispersions of polyisocyanate, macrodiol and hydroxyacrylate are used as leather coating agents, but the preparation of these compounds is carried out as well as the preparation of those described in EP-AO 287 736 or in EP-AO 381 862 hydrophilic polyurethanes not in the manner according to the invention.

Also not known is the specific use according to the invention of such urethane (meth) acrylates.

EP-A 287 736 discloses a preparation of urethane (meth) acrylates in which, in Example 1, a polyol is initially introduced, to which first the isocyanate and finally a hydroxy-functional acrylate are added.

According to EP-A 381 862, isocyanates are prepared for the preparation of urethane (meth) acrylates, to which polyol and hydroxy-functional acrylate are added.

This leads to a significant proportion of unreacted hydroxy-functional acrylate.

WO 06/89935 describes the preparation of urethane (meth) acrylates by initially introducing a mixture of polyols and hydroxy-functional acrylate and adding it to this isocyanate. However, polyethers as polyols are mentioned only within long lists.

The object of the present invention was to develop a preparation process for radiation-curable, water-soluble or emulsifiable urethane (meth) acrylates, in which the hydroxyl-functional (meth) acrylate used as starting material can be reacted as completely as possible, which show a reduced yellowing and improved adhesion effect the coating on the substrate pretreated with the task.

The object has been achieved by a process for preparing urethane (meth) acrylates (A) by reacting the components

(a) at least one isocyanate having at least 2 isocyanate functions, (b) at least one polyalkylene oxide polyether having at least 2 hydroxyl functions,

(c) at least one hydroxy-functional (meth) acrylate having exactly one hydroxyl function and at least one (meth) acrylate function,

(d) at least one compound having at least one isocyanate-reactive group and at least one acid function,

(e) optionally at least one compound having at least one isocyanate-reactive group and at least one basic group for neutralization of the acid groups of component (d),

(f) optionally at least one monoalcohol having exactly one hydroxyl function,

(g) optionally at least one di- or polyamine,

wherein the preparation of the urethane (meth) acrylate (A) can optionally be carried out in the presence of at least one reactive diluent (B) and / or optionally in the presence of at least one solvent,

in which the components (b), (c), (d) and, if present, (e) are at least partly introduced from the components (a) to (f) and the isocyanate (a) is added to this mixture of the components initially introduced ,

The urethane (meth) acrylates (A) thus obtained have at least one of the following advantages:

they contain a lower content of free component (c) than compounds (A) prepared by other processes, - they show a lower yellowing in paints than products obtained by other manufacturing processes, and

- improve the adhesion of further paint layers on the substrate.

With particular advantage, the mixtures obtained by the process described above, in particular those obtained by the process described above, can be used as a primer, in particular as a primer for bonding wood and wood-containing substrates.

Component (a) is at least one, preferably exactly one isocyanate having at least 2 isocyanate functions, preferably 2 to 3 and particularly preferably exactly 2 isocyanate functions. The isocyanates used may be polyisocyanates or, preferably, monomeric diisocyanates which may be aromatic, aliphatic or cycloaliphatic, which will be referred to briefly as (cyclo) aliphatic in this document.

Aromatic isocyanates are those which contain at least one aromatic ring system, ie both purely aromatic and also araliphatic compounds.

Cycloaliphatic isocyanates are those which contain at least one cycloaliphatic ring system.

Aliphatic isocyanates are those which contain exclusively straight or branched chains, ie acyclic compounds.

The monomeric isocyanates are preferably diisocyanates which carry exactly two isocyanate groups.

In principle, higher isocyanates having an average of more than 2 isocyanate groups are also considered. For example, triisocyanates such as triisocyanato, 2,4,6-triisocyanatotoluene, triphenylmethane triisocyanate or 2,4,4'-triisocyanato-diphenyl ether or the mixtures of di-, tri- and higher polyisocyanates suitable for example by phosgenation of corresponding aniline / Formaldehyde condensates are obtained and represent methylene bridges Polyphenylpolyiso- cyanate.

These monomeric isocyanates have essentially no reaction products of the isocyanate groups with themselves.

The monomeric isocyanates are preferably isocyanates having 4 to 20 C atoms. Examples of customary diisocyanates are aliphatic diisocyanates such as tetramethylene diisocyanate, 1,5-pentamethylene diisocyanate, hexamethylene diisocyanate (1,6-diisocyanatohexane), octamethylene diisocyanate, decamethylene diisocyanate, dodecamethylene diisocyanate, tetradecamethylene diisocyanate, derivatives of lysine diisocyanate, trimethylhexane diisocyanate or tetramethylhexane diisocyanate, cycloaliphatic diisocyanates such as 1, 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 and 3 (or 4), 8 (resp. 9) -Bis (isocyanatomethyl) -tricyclo [5.2.1.0 ²⁶ ] decane isomer mixtures, and aromatic diisocyanates such as 2,4- or 2,6-toluene diisocyanate and their isomer mixtures, m- or p-xylylene diisocyanate, 2,4'- or 4,4'-diisocyanatodiphenylmethane and isomer mixtures thereof, 1, 3 or 1, 4-phenylene diisocyanate, 1-chloro-2,4-phenylene diisocyanate, 1, 5-naphthylene diisocyanate, Diphenylene-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.

Particularly preferred (cyclo) aliphatic isocyanates are 1, 6

Hexamethylene diisocyanate, 1, 3-bis (isocyanatomethyl) cyclohexane, isophorone diisocyanate and 4,4'- or 2,4'-di (isocyanatocyclohexyl) methane, most preferably isophorone diisocyanate and 1, 6-hexamethylene diisocyanate, is particularly preferred isophorone.

Preferred aromatic isocyanates are 2,4- or 2,6-toluene diisocyanate and their mixtures of isomers, and 2,4'- or 4,4'-diisocyanatodiphenylmethane and their isomer mixtures, more preferably 2,4- or 2,6-toluene diisocyanate and their isomer mixtures in the ratio of about 80:20. Also conceivable is the use of pure 2,4-toluene diisocyanate.

There may also be mixtures of said isocyanates.

Isophorone diisocyanate is usually present as a mixture, namely the cis and trans isomers, usually in the ratio of about 60:40 to 80:20 (w / w), preferably in the ratio of about 70:30 to 75 : 25 and most preferably in the ratio of about 75:25.

Dicyclohexylmethane-4,4'-diisocyanate may also be present as a mixture of the different cis and trans isomers.

For the present invention, it is possible to use both those diisocyanates which are obtained by phosgenation of the corresponding amines and those which are prepared without the use of phosgene, ie by phosgene-free processes. According to EP-AO 126 299 (US Pat. No. 4,596,678), EP-A-126 300 (US Pat. No. 4,596,679) and EP-A-355 443 (US Pat. No. 5,087,739), for example, (cyclo) aliphatic diisocyanates, for example, such as 1, 6-hexamethylene diisocyanate (HDI), isomeric aliphatic diisocyanates having 6 carbon atoms in the alkylene radical, 4,4'- or 2,4'-di (isocyanatocyclohexyl) methane and 1-isocyanato-S-isocyanato-methyl-S ^^ -trimethylcyclohexane (isophorone diisocyanate or IPDI) are prepared by reacting the (cyclo) aliphatic diamines with, for example, urea and alcohols to (cyclo) aliphatic biscarbamic acid esters and their thermal cleavage into the corresponding diisocyanates and alcohols. The synthesis is usually carried out continuously in a cyclic process and optionally in the presence of N-unsubstituted carbamic acid esters, dialkyl carbonates and other by-products recycled from the reaction process. Diisocyanates obtained in this way generally have one very low or even non-measurable level of chlorinated compounds, which is advantageous, for example, in applications in the electronics industry.

In one embodiment of the present invention, the isocyanates used have a total hydrolyzable chlorine content of less than 200 ppm, preferably less than 120 ppm, more preferably less than 80 ppm, most preferably less than 50 ppm, in particular less than 15 ppm and especially less than 10 ppm. This can be measured, for example, by ASTM D4663-98. Of course, it is also possible to use monomeric isocyanates having a higher chlorine content, for example up to 500 ppm.

Of course, mixtures of such monomeric isocyanates, which have been obtained by reacting the (cyclo) aliphatic diamines with, for example, urea and alcohols and cleavage of the obtained (cyclo) aliphatic biscarbamic, with such diisocyanates obtained by phosgenation of the corresponding amines, be used.

Conceivable, although less preferred, is the use of polyisocyanates in addition to or instead of the monomeric isocyanates.

The polyisocyanates to which the monomeric isocyanates can be oligomerized are typically characterized as follows:

The average NCO functionality of such compounds is generally at least 1.8, and may be up to 8, preferably 2 to 5 and more preferably 2.4 to 4.

The content of isocyanate groups after the oligomerization, calculated as NCO = 42 g / mol, is usually from 5 to 25% by weight.

The polyisocyanates are preferably the following compounds:

1) isocyanurate polyisocyanates of aromatic, aliphatic and / or cycloaliphatic diisocyanates. Particular preference is given here to the corresponding aliphatic and / or cycloaliphatic isocyanato-isocyanurates and in particular those based on hexamethylene diisocyanate and isophorone diisocyanate. The isocyanurates present are, in particular, trisisocyanatoalkyl or trisisocyanatocycloalkyl isocyanurates, which are cyclic trimers of the diisocyanates, or mixtures with their higher homologues containing more than one isocyanurate ring. The isocyanato-isocyanurates generally have an NCO content of 10 to 30 wt .-%, in particular 15 to 25 wt .-% and an average NCO- Functionality from 2.6 to 8.

2) polyisocyanates containing uretdione groups with aromatic, aliphatic and / or cycloaliphatic bonded isocyanate groups, preferably aliphatically and / or cycloaliphatically bonded and in particular those derived from hexamethylene diisocyanate or isophorone diisocyanate. Uretdione diisocyanates are cyclic dimerization products of diisocyanates.

The polyisocyanates containing uretdione groups are obtained in the context of this invention in a mixture with other polyisocyanates, in particular those mentioned under 1). For this purpose, the diisocyanates can be reacted under reaction conditions under which both uretdione groups and the other polyisocyanates are formed, or first the uretdione groups formed and these are then reacted to the other polyisocyanates or the diisocyanates first to the other polyisocyanates and these then to uretdione groups-containing Products are implemented.

3) biuret polyisocyanates having aromatic, cycloaliphatic or aliphatic bound, preferably cycloaliphatic or aliphatic bound isocyanate groups, in particular tris (6-isocyanatohexyl) biuret or its

Mixtures with its higher homologs. These biuret polyisocyanates generally have an NCO content of 18 to 22 wt .-% and an average NCO functionality of 2.8 to 6.

4) polyisocyanates containing urethane and / or allophanate groups with aromatically, aliphatically or cycloaliphatically bonded, preferably aliphatically or cycloaliphatically bonded isocyanate groups, as described, for example, by reacting excess amounts of diisocyanate, for example hexamethylene diisocyanate or isophorone diisocyanate, with monovalent or polyvalent Al koholen. These urethane and / or allophanate-containing polyisocyanates generally have an NCO content of 12 to 24 wt .-% and an average NCO functionality of 2.5 to 4.5. Such urethane and / or allophanate group-containing polyisocyanates can be used uncatalyzed or, preferably, in the presence of catalysts such as ammonium carboxylates or hydroxides, or allophanatization catalysts, e.g. Zn (I I) compounds, each in the presence of mono-, di- or polyvalent, preferably monohydric alcohols produced.

5) oxadiazinetrione-containing polyisocyanates, preferably derived from hexamethylene diisocyanate or isophorone diisocyanate. Such oxadiazinetrione-containing polyisocyanates are of diisocyanate and carbon dioxide accessible.

6) polyisocyanates containing iminooxadiazinedione groups, preferably derived from hexamethylene diisocyanate or isophorone diisocyanate. Such iminooxadiazine-dione-containing polyisocyanates can be prepared from diisocyanates by means of special catalysts.

7) Uretonimine-modified polyisocyanates.

8) carbodiimide-modified polyisocyanates.

9) Hyperbranched polyisocyanates, as are known, for example, from DE-A1 10013186 or DE-A1 10013187.

10) polyurethane-polyisocyanate prepolymers of di- and / or polyisocyanates with alcohols.

1 1) polyurea-polyisocyanate prepolymers.

12) The polyisocyanates 1) -11), preferably 1), 3), 4) and 6) may, after their preparation, comprise polyisocyanates having aryl, cycloaliphatic or aliphatic bound groups in biuret group or urethane / allophanate groups, preferably (cyclo) aliphatically bound isocyanate groups are transferred. The formation of biuret groups takes place, for example, by addition of water or reaction with amines. The formation of urethane and / or allophanate groups by reaction with mono-, di- or polyhydric, preferably monohydric alcohols, optionally in the presence of suitable catalysts. These biuret or urethane / allophanate groups containing polyisocyanates generally have an NCO content of 18 to 22 wt .-% and an average NCO functionality of 2.8 to 6 on.

13) Hydrophilic modified polyisocyanates, i. Polyisocyanates which contain, in addition to the groups described under 1-12, those which formally arise by addition of molecules with NCO-reactive groups and hydrophilicizing groups to the isocyanate groups of the above molecules. The latter are nonionic groups such as alkyl polyethylene oxide and / or ionic, which are derived from phosphoric acid, phosphonic acid, sulfuric acid or sulfonic acid, or their salts.

14) Modified polyisocyanates for dual-cure applications, ie polyisocyanates containing in addition to the groups described under 1-12 those formally by the addition of molecules with NCO-reactive groups and by UV or actinic radiation crosslinkable groups are formed on the isocyanate groups of the above molecules. These molecules are, for example, hydroxyalkyl (meth) acrylates and other hydroxy-vinyl compounds.

The diisocyanates or polyisocyanates listed above may also be present at least partially in blocked form.

Classes of compounds used for blocking are described in D.A. Wicks, Z. W. Wicks, Progress in Organic Coatings, 36, 148-172 (1999), 41, 1-83 (2001) and 43, 131-140 (2001).

Examples of classes of compounds used for blocking are phenols, imidazoles, triazoles, pyrazoles, oximes, N-hydroxyimides, hydroxybenzoic acid esters, secondary amines, lactams, CH-acidic cyclic ketones, malonic esters or alkyl acetoacetates.

In a preferred embodiment of the present invention, the polyisocyanate is selected from the group consisting of isocyanurates, biurets, urethanes and allophanates, preferably from the group consisting of isocyanurates, urethanes and allophanates, particularly preferably from the group consisting of isocyanurates and allophanates, in particular it is an isocyanurate group-containing polyisocyanate.

In an embodiment to be mentioned, the polyisocyanate is isocyanurate group-containing polyisocyanates of 1,6-hexamethylene diisocyanate.

In a further embodiment, the polyisocyanate is a mixture of isocyanurate group-containing polyisocyanates of 1,6-hexamethylene diisocyanate and of isophorone diisocyanate.

In a particularly preferred embodiment, the polyisocyanate is a mixture comprising low-viscosity polyisocyanates, preferably polyisocyanates containing isocyanurate groups, having a viscosity of 600-1500 mPa ^* s, in particular less than 1200 mPa ^* s, low-viscosity urethanes and / or allophanates having a viscosity of 200-1600 mPa ^* s, in particular 600-1500 mPa ^* s, and / or iminooxadiaindione groups-containing polyisocyanates.

Component (b) is at least one, preferably exactly one polyalkylene oxide polyether having at least 2 hydroxyl functions, preferably 2 to 4 hydroxy functions, more preferably 2 to 3 and most preferably exactly 2 hydroxy functions. For example, component (b) may be alkoxylated diols or polyols of the formulas (Ia) to (Id),

1 ^X

(Ia) (Ib) (Ic)

To act (id),

wherein

R ¹ and R ² independently of one another denote hydrogen or C 1 -C 6 -alkyl optionally substituted by aryl, alkyl, aryloxy, alkyloxy, heteroatoms and / or heterocycles,

k, I, m, q independently of one another are each an integer from 1 to 15, preferably 1 to 10 and particularly preferably 1 to 7, and

each X, for i = 1 to k, 1 to I, 1 to m and 1 to q can be independently selected from the group -CH ₂ -CH ₂ -O-, -CH ₂ -CH (CHs) -O- , -CH (CHs) -CH ₂ -O-, -CH ₂ - C (CH) ₂ -O-, -C (CHs) 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 (CHs) -O- and -CH (CHs) -CH ₂ -O-, and more preferably -CH ₂ -CH ₂ -O-,

where Ph is phenyl and Vin is vinyl.

Therein Cis-alkyl which is optionally substituted by aryl, alkyl, aryloxy, alkyloxy, heteroatoms and / or heterocycles are, for example, methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, pentyl, hexyl , Heptyl, octyl, 2-ethylhexyl, 2,4,4-trimethylpentyl, decyl, dodecyl, tetradecyl, heptadecyl, octadecyl, 1, 1-dimethylpropyl, 1, 1-dimethylbutyl, 1, 1, 3,3-tetramethylbutyl , preferably methyl, ethyl or n-propyl, most preferably methyl or ethyl. However, preferred components (b) are polyalkylene ethers having exactly 2 hydroxyl groups, which are essentially, preferably exclusively, formally synthesized from ethylene oxide and / or propylene oxide. Such compounds are often referred to as polyethylene / polypropylene glycols or generally as polyalkylene glycols.

The structure of such polyalkylene glycols is usually as follows

wherein

Xi for each i = 1 to n can be independently selected from the group consisting of -CH ₂ -CH ₂ -O-, -CH ₂ -CH (CHs) -O- and -CH (CHs) -CH ₂ -O - and more preferably -CH ₂ -CH ₂ -O- may be, and

n can be an integer from 5 to 60, preferably from 7 to 50 and particularly preferably from 10 to 45.

The number average molecular weight M _n is preferably between 500 and 2000 g / mol. The OH numbers (according to DIN 53240, potentiometric) are preferably in a range of about 20 to 300 mg KOH / g polymer.

The reaction of the alcohols or water with an alkylene oxide is known per se to the person skilled in the art. Possible implementation forms can be found in Houben-Weyl, Methods of Organic Chemistry, 4th Edition, 1979, Thieme Verlag Stuttgart, Ed. Heinz Kropf, Volume 6/1 a, Part 1, pages 373-385.

Preferably, the preparation is carried out as follows:

The polyhydric alcohol or water, if appropriate in a suitable solvent, such as benzene, toluene, xylene, tetrahydrofuran, hexane, pentane or petroleum ether, dissolved, at temperatures between 0 ⁰ C and 120 ⁰ C, preferably between 10 and 100 ⁰ C and more preferably between 20 and 80 ⁰ C, preferably under protective gas, such as nitrogen, submitted. For this purpose, the alkylene oxide is added continuously or in portions, optionally at a temperature of -30 ⁰ C to 50 ⁰ C dissolved in one of the abovementioned solvents, with thorough mixing so that the temperature of the reaction mixture between 120 and 180 ⁰ C, preferably between 120 and 150 ⁰ C. The reaction can take place under a pressure of up to 60 bar, preferably up to 30 bar and particularly preferably up to 10 bar.

The amount of alkylene oxide is adjusted so that per mole of polyhydric alcohol up to (1, 1 x (k + I + m + q)) mol of alkylene oxide, preferably up to (1, 05 x (k + I + m + q )) mol of alkylene oxide and particularly preferably (k + I + m + q) mol of alkylene oxide are added, wherein k, I, m and q have the abovementioned meanings.

Optionally, up to 50 mol%, based on the polyhydric alcohol, particularly preferably up to 25 mol% and very particularly preferably up to 10 mol% of a catalyst for acceleration may be added, for example water (if this is not already present as starting material in the reaction mixture is), monoethanolamine, diethanolamine, triethanolamine, dimethylaminoethanolamine, ethylene glycol or diethylene glycol, and also alkali metal hydroxides, alcoholates or hydrotalcite, preferably alkali metal hydroxides in water.

After complete metered addition of the alkylene oxide is generally 10 to 500 minutes, preferably 20 to 300 minutes, more preferably 30 to 180 minutes at temperatures between 30 and 220 ⁰ C, preferably 80 to 200 ⁰ C and particularly preferably 100 to 180 ⁰ post-reacted let the temperature remain the same or can be raised gradually or continuously.

The conversion of alkylene oxide is preferably at least 90%, particularly preferably at least 95% and very particularly preferably at least 98%. Possible residues of alkylene oxide can be stripped out of the reaction mixture by passing a gas, for example nitrogen, helium, argon or steam.

The reaction can be carried out, for example, batchwise, semicontinuously or continuously in a stirred reactor or else continuously in a tubular reactor with static mixers.

Preferably, the reaction is carried out completely in the liquid phase.

The resulting reaction product can be further processed in crude or processed form.

If further use in pure form is desired, the product can be purified, for example, by crystallization and solid / liquid separation.

The yields are usually over 75%, usually over 80% and often over 90%.

If the reaction is carried out with a basic catalyst, for example alkali metal hydroxides, preferably sodium or potassium hydroxide, it may be expedient to subsequently neutralize the catalyst residues still present after the reaction with, for example, acetic acid. This results in that in the polyalkylene glycol is still contained alkali metal acetate, which catalytically in subsequent reactions can be active. But it is also possible to remove the alkali metal acetate contained, for example by treatment with an ion exchanger.

The component (c) is at least one, preferably 1 to 2, more preferably exactly one hydroxy-functional (meth) acrylate having exactly one hydroxyl function and at least one, preferably 1 to 3, more preferably exactly one (Meth ) acrylate function.

Components (c) can be partial esters of acrylic acid or methacrylic acid with diols or polyols which preferably have 2 to 20 C atoms and 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, 2, 1, 3 or 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, trimethylol - Butane, pentaerythritol, ditrimethylolpropane, erythritol, sorbitol, poly-THF having a molecular weight between 162 and 2000, poly-1, 3-propanediol having a molecular weight between 134 and 400 or polyethylene glycol having a molecular weight between 238 and 458. Further also esters or amides of (meth) acrylic acid with amino alcohols z. For example, 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 diethylenetriamine be used.

Examples of amides of ethylenically unsaturated carboxylic acids with amino alcohols are hydroxyalkyl (meth) acrylamides such as N-hydroxymethylacrylamide, N-hydroxymethylmethacrylamide, N-hydroxyethylacrylamide, N-hydroxymethylmethacrylamide and 5-hydroxy-3-oxapentyl (meth) acrylamide.

Preference is given to using 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 , 6-hexanediol mono (meth) acrylate, glycerol di (meth) acrylate, trimethylolpropane di (meth) acrylate, pentaerythritol tri (meth) acrylate, 2-hydroxyethyl (meth) acrylamide, 2-hydroxypropyl (meth) acrylamide or 3-hydroxypropyl (meth ) acrylamide. Particularly preferred are 2-hydroxyethyl acrylate, 2-

Hydroxyethyl methacrylate, 2- or 3-hydroxypropyl acrylate, 1, 4-butanediol monoacrylate, 3- (acryloyloxy) -2-hydroxypropyl (meth) acrylate and the monoacrylates of polyethylene glycol of molecular weight from 106 to 238.

Very particular preference is given to 2-hydroxyethyl acrylate. Component (c) may also be technical mixtures of the acrylation of trimethylolpropane, pentaerythritol, ditrimethylolpropane or dipentaerythritol. These are mostly mixtures of complete and incomplete acrylated polyols. In this case, preference would be given to technical mixtures of the acrylation of pentaerythritol, which generally have an OH number in accordance with DIN 53240 of 99 to 115 mg KOH / g and consist predominantly of pentaerythritol triacrylate and pentaerythritol tetraacrylate, and may contain minor amounts of pentaerythritol diacrylate. This has the advantage that pentaerythritol tetraacrylate is not incorporated into the polyurethane of the invention, but at the same time acts as a reactive diluent (B).

Component (d) is at least one, preferably exactly one compound having at least one, for example 1 to 3, particularly preferably 2 to 3 and very particularly preferably exactly 2 isocyanate-reactive group and at least one, preferably exactly one acid function.

Suitable acid groups are carboxylic acid or sulfonic acid groups, preferably carboxylic acid groups.

Groups that are reactive toward isocyanate groups are selected from hydroxy, mercapto, primary and / or secondary amino groups, preferably hydroxy groups.

Suitable compounds (d) are, in particular, aliphatic monomercapto, monohydroxy and monoamino and iminocarboxylic acids and corresponding sulfonic acids, such as mercaptoacetic acid (thioglycolic acid), mercaptopropionic acid, mercaptosuccinic acid, hydroxyacetic acid, hydroxypropionic acid (lactic acid), hydrosuccinic acid, hydroxypivalic acid, Dimethylolpropionic acid, dimethylolbutyric acid, hydroxydecanoic acid, hydroxydodecanoic acid, 12-hydroxystearic acid, hydroxyethanesulfonic acid, hydroxypropanesulfonic acid, mercaptoethanesulfonic acid, mercaptopropanesulfonic acid, aminoethanesulfonic acid, aminopropanesulfonic acid, glycine (aminoacetic acid), N-cyclohexylaminoethanesulfonic acid, N-cyclohexylaminopropanesulfonic acid, or iminodiacetic acid.

Preference is given to dimethylolpropionic acid and dimethylolbutyric acid, dimethylolpropionic acid being particularly preferred.

The optional component (e) is at least one, preferably exactly one compound having at least one, for example 1 to 3, particularly preferably 2 to 3 and very particularly preferably exactly 2 isocyanate-reactive group and at least one, preferably exactly one basic Groups capable of neutralizing the acid groups of component (d). Suitable basic groups are amines, for example primary, secondary or tertiary amines, particular preference is given to tertiary amines. Preferably, the neutralization or partial neutralization of the acid groups in (d) with amines such as ethanolamine or diethanolamine, or triethanolamine or 2-propanolamine or dipropanolamine, or tripropanolamine and especially with tert. Amines, such as triethylamine, triethanolamine, dimethylethanolamine or diethylethanolamine. Particularly preferred are N-methyldiethanolamine and N-ethyldiethanolamine. The amounts of chemically bound basic groups introduced and the extent of neutralization of the acid groups (which is usually from 40 to 100% of the equivalence base) should preferably be sufficient to ensure dispersion of the polyurethanes in an aqueous medium, which is familiar to the person skilled in the art ,

Instead of or in addition to component (e), it may also be possible to use acidic groups with inorganic or organic bases without isocyanate-reactive groups, such as alkali metal and alkaline earth metal hydroxides, oxides, carbonates,

bicarbonates and ammonia or tert. Use amines for neutralization or partial neutralization. Preferably, the neutralization or partial neutralization with sodium hydroxide or potassium hydroxide or tert. Amines, such as triethylamine, tri-n-butylamine or ethyl diisopropylamine. The amounts of introduced chemically bonded acid groups and the extent of neutralization of the acid groups (which is usually 40 to 100% of the equivalent) should preferably be sufficient to ensure dispersion of the polyurethanes in an aqueous medium, which is familiar to the person skilled in the art.

The optional component (f) is at least one monoalcohol which has exactly one hydroxyl function and, moreover, no further functional group.

Examples are methanol, ethanol, n-propanol, isopropanol and n-butanol, preferably methanol.

The function of the compounds (f) is to saturate any remaining unreacted isocyanate groups in the preparation of the urethane (meth) acrylates (A).

Depending on the components used, the viscosity of the urethane (meth) acrylate (A) can be up to 25, preferably less than 20 Pas.

Therefore, the preparation of the urethane (meth) acrylate (A) may optionally, though less preferably, be carried out in the presence of at least one reactive diluent (B). This is at least one radiation-curable compound which, in addition to radically polymerizable groups, preferably acrylate or methacrylate groups, contains no isocyanate- or hydroxyl-reactive groups and also has a low viscosity, preferably less than 150 mPas (in this document Viscosity at 25 ⁰ C according to DIN EN ISO 3219 / A.3 in a cone-plate system with a speed gradient of 1000 S " ¹ indicated, unless otherwise stated).

Preferred compounds (B) have one to six (meth) acrylate groups, more preferably one to four, most preferably two to four.

Particularly preferred compounds (B) have a boiling point of more than 200 ⁰ C at atmospheric pressure.

Reactive diluents are generally available in P. KT. Oldring (Editor), Chemistry & Technology of UV & EB Formulations for Coatings, Inks & Paints, Vol. II, Chapter III: Reactive Diluents for UV & EB Curable Formulations, Wiley and SITA Technology, London 1997.

Reactive diluents are, for example, esters of (meth) acrylic acid with alcohols having from 1 to 20 carbon atoms, e.g. Methyl (meth) acrylate, (meth) acrylic acid ethyl ester, butyl (meth) acrylate, (meth) acrylic acid 2-ethylhexyl ester, dihydrodicyclopentadienyl acrylate, vinylaromatic compounds, e.g. Styrene, divinylbenzene, α, β-unsaturated nitriles, e.g. Acrylonitrile, methacrylonitrile, α, β-unsaturated aldehydes, e.g. Acrolein, methacrolein, vinyl esters, e.g. Vinyl acetate, vinyl propionate, halogenated ethylenically unsaturated compounds, e.g. Vinyl chloride, vinylidene chloride, conjugated unsaturated compounds, e.g. Butadiene, isoprene, chloroprene, monounsaturated compounds, e.g. Ethylene, propylene, 1-butene, 2-butene, iso-butene, cyclic monounsaturated compounds, e.g. Cyclopentene, cyclohexene, cyclododecene, N-vinylformamide, allylacetic acid, vinylacetic acid, monoethylenically unsaturated carboxylic acids having 3 to 8 carbon atoms and their water-soluble alkali metal, alkaline earth metal or ammonium salts such as, for example: acrylic acid, methacrylic acid, dimethylacrylic acid, ethacrylic acid, maleic acid, citraconic acid , Methylenemalonic acid, crotonic acid, fumaric acid, mesaconic acid and itaconic acid, maleic acid, N-vinylpyrrolidone, N-vinyllactams, such as N-vinylcaprolactam, N-vinyl-N-alkylcarboxamides or N-vinylcarboxamides, such as. N-vinylacetamide, N-vinyl-N-methylformamide and N-vinyl-N-methylacetamide or vinyl ethers, e.g. Methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, sec-butyl vinyl ether, isobutyl vinyl ether, tert-butyl vinyl ether, and mixtures thereof.

Examples of compounds (B) having at least two free-radically polymerizable C =C double bonds are in particular the diesters and polyesters of the abovementioned α, ß-ethylenically unsaturated mono- and / or dicarboxylic acids with diols or polyols. Particular preference is given to hexanediol diacrylate, hexanediol dimethacrylate, octanedioldiacrylate, octanediol dimethacrylate, nonanediol diacrylate, nonanediol dimethacrylate, di-candioldiacrylate, decanediol dimethacrylate, pentaerythritol diacrylate, dipentaerythritol tetraacrylate, dipentaerythritol triacrylate, pentaerythritol tetraacrylate, etc. The esters of alkoxylated polyols with α, β-ethylenically unsaturated are also preferred Mono- and / or dicarboxylic acids such. As the polyacrylates or methacrylates of alkoxylated trimethylolpropane, glycerol or pentaerythritol and diethylene glycol, triethylene glycol, dipropylene glycol or tripropylene glycol. Also suitable are the esters of alicyclic diols, such as cyclohexanediol di (meth) acrylate and bis (hydroxymethyl-ethyl) cyclohexanedi (meth) acrylate. Further suitable reactive diluents are trimethylolpropane monoformal acrylate, glycerol formal acrylate, 4-tetrahydropyranyl acrylate, 2-tetrahydropyranyl methacrylate and tetrahydrofurfuryl acrylate.

Optionally, the preparation of the polyurethane can be carried out in at least one, preferably exactly one solvent. Preference is given here to water-miscible solvents, particularly preferably those having a lower boiling point than water. Examples of these are acetone, tetrahydrofuran, butanone, diethyl ketone, cyclic or open-chain carbonates, N-methylpyrrolidone or N-ethylpyrrolidone.

The urethane (meth) acrylate (A) and / or the reactive diluent (B) may optionally be added to a primary or secondary amine (h) to activate the (meth) acrylate groups.

In the compounds (h), the number of aminic hydrogen atoms (N-H) of primary and / or secondary amino groups is preferably 1 to 6, more preferably 2 to 4.

For example, the number of aminic hydrogen atoms in a compound having two primary amino groups 4 and in a compound having one primary and one secondary amino group 3.

Primary or secondary amino groups in compounds (h) add to acrylic groups or methacrylic groups according to a Michael addition. This so-called A- minmodifizierung causes an increase in the reactivity of the thus modified

(Meth) acrylates and this increased reactivity then reduces the tack of the resulting coatings.

Michael addition to (meth) acrylate groups turns secondary amino groups into secondary amino groups, which can in turn be added to (meth) acrylic groups to form tertiary amino groups. Suitable compounds (h) having at least one primary and / or secondary amino group are generally of low molecular weight and preferably have a molecular weight of less than 1000.

Mention may be made, for example, of primary monoamines such as C 1 -C 20 -alkylamines, in particular n-butylamine, n-hexylamine, 2-ethylhexylamine, octadecylamine, isopropanolamine or methoxypropylamine, cycloaliphatic amines such as cyclohexylamine and (hetero) aromatic-group-containing amines such as benzylamine, 1- ( 3-aminopropyl) imidazole and tetrahydrofurfurylamine.

Compounds with 2 primary amino groups are e.g. C 1 -C 20 -alkylenediamines, such as ethylenediamine, butylenediamine, neopentanediamine or hexamethylenediamine.

Compounds with secondary amino groups are, for example, dimethylamine, diethylamine, diisopropylamine or di-n-butylamine, and piperidine, pyrrolidine and morpholine.

Also mentioned are 4,9-dioxadodecane-1, 12-diamine, 4,7,10-trioxatridecane-1, 13-diamine, 4,4'-diaminodicyclohexylmethane and isophoronediamine. As compounds with primary or secondary amino groups with at least one hydroxyl group may be mentioned alkanolamines, e.g. Mono- or diethanolamine, aminoethoxyethanol, aminoethylethanolamine, 2-aminopropan-1-ol, dipropanolamine, 2-aminobutan-1-ol, 3-aminopropan-1-ol, hydroxyethylpiperazine, piperazine, imidazole, etc.

Compounds containing primary and secondary amino groups are, for example 3-amino-1- methylaminopropane, diethylenetriamine, triethylenetetramine, dipropylenetriamine, N ₁ N'-bis (3-aminopropyl) ethylenediamine.

Preferably, the compounds (h) are used with one or more primary and / or secondary amino groups in such quantities that to 1 mole of the

(Meth) acrylate groups in the compounds (A) and / or (B) 0.005 to 0.4, preferably 0.01 to 0.2 mol, particularly preferably 0.02 to 0.1 mol of aminic hydrogen atoms of primary or secondary amino groups in come the compounds (h).

The optional addition of the compound (h) is usually carried out after completion of the preparation of the urethane (meth) acrylate, i. after the reaction of components (a) to (f) is substantially completed.

The composition of the urethane (meth) acrylates is usually as follows:

(a) 100 mol% isocyanate functions, (b) 25 to 75 mol% of hydroxy functions (based on isocyanate functions in (a)), preferably 40 to 60 mol%,

(c) 10 to 80 mol% of hydroxy functions (based on isocyanate functions in (a)), preferably 20 to 50 mol%,

(d) 0 to 20 mol% of hydroxy functions (based on isocyanate functions in (a)), preferably 0 to 10 mol%,

(e) 0 to 5 mol% isocyanate-reactive groups (based on isocyanate functions in (a)),

(f) 0 to 5 mol% of hydroxy functions (based on isocyanate functions in (a)),

with the proviso that the sum of the hydroxy functions in components (b), (c), (d), (e) and (f) gives 100 mol% of hydroxy functions (based on isocyanate functions in (a)).

It may be useful to use the component (a) containing isocyanate groups in excess, for example up to 120 mol%, preferably up to 115 mol%, particularly preferably up to 110 mol% and very particularly preferably up to 105 mol %. This is particularly preferred if at least one of the components used, in particular the hygroscopic compound (b), contains water which reacts with isocyanate functions in competition with hydroxyl functions.

The reactive diluent (B) may be present in the amount of 0 to 3 times the amount of the urethane (meth) acrylate (A) during the reaction and / or after the preparation of the urethane (meth) acrylate (A), preferably in 0.1 to 2 times the amount.

The preparation of the polyurethanes is advantageously carried out by reacting the components under consideration of the order of addition according to the invention in the melt or in the presence of an inert, water-miscible solvent (see above) at temperatures of 20 to 160, preferably 50 to 100 ⁰ C, wherein the reaction time is usually 2 to 10 hours. By the concomitant use of known per se catalytically active substances such as dibutyltin dilaurate,

Tin (II) octoate or 1,4-diazobicyclo (2,2,2) octane, usually in amounts of from 10 to 500 ppm, based on the solvent-free reaction mixture, can accelerate the reaction. Subsequently, if appropriate, the mixture is diluted with a water-miscible solvent; if not already done, ionogenic groups may be ionized by neutralization, water is added, and, if appropriate, di- or polyamines are stirred in to extend the chain. Thereafter, the optionally used organic solvents are usually distilled off, which is why such solvents are preferred whose boiling point is below the boiling point of water. Optionally, the di- or polyamines for chain extension may also be added prior to dispersion with water. The amount of water added is usually such that the aqueous polyurethane preparations according to the invention have a solids content of from 10 to 80% by weight.

According to the invention for the preparation of the urethane (meth) acrylate (A) of the components (a) to (f) at least the components (b) and (c) and optionally (d) at least partially, preferably completely presented and added to this mixture of Components the isocyanate (a) added.

For this purpose, preferably at least half of the planned amount of component (b) is used, preferably at least 65%, particularly preferably at least 75%, and in particular the complete amount.

Furthermore, preferably at least half of the planned amount of component (c) is used, preferably at least 65%, particularly preferably at least 75%, and in particular the complete amount.

If component (d) is used, preferably at least half of the planned amount of component (d) is used, preferably at least 65%, particularly preferably at least 75%, and in particular the complete amount.

The isocyanate (a) is then added to this mixture of components (b) and (c) and optionally (d). This can be done continuously, in several portions or in one addition.

The reaction mixture is then stirred at temperatures of 50 to 80 ⁰ C over a time cavities 4 to 10 hours, preferably from 6 to 10 hours with stirring or pump environmental reacted with each other.

During the reaction, the temperature can remain the same or can be increased continuously or stepwise.

The reaction is preferably accelerated by adding a suitable catalyst. Such catalysts are known from the literature, for example from G. Oertel (ed.), Polyurethane, 3rd edition 1993, Carl Hanser Verlag, Munich - Vienna, pages 104 to 1 10, chapter 3.4.1. "Catalysts", preferred are organic amines, in particular tertiary aliphatic, cycloaliphatic or aromatic amines, Brønsted acids and / or Lewis acidic organometallic compounds, particularly preferred are Lewis acidic organometallic compounds. Preferably, these are Lewis acid organic metal compounds, for example, tin compounds in question, such as tin (II) salts of organic carboxylic acids, such as tin (II) diacetate, tin (II) dioctoate, tin (II) bis (ethylhexanoate ) and tin (II) dilaurate and the dialkyltin (IV) salts of organic carboxylic acids, for example dimethyltin diacetate, dibutyltin diacetate, dibutyltin dibutyrate, dibutyltin bis (2-ethylhexanoate), dibutyltin dilaurate, dibutyltin maleate, dioctyltin dilaurate and dioctyltin diacetate. In addition, zinc (II) salts can be used, such as zinc (II) dioctoate.

It is also conceivable to carry out the reaction without catalyst, but in this case the reaction mixture must be exposed to higher temperatures and / or the reaction time must be prolonged.

In order to avoid undesired polymerization of the (meth) acrylate groups during the reaction, polymerization inhibitors may be added. Such inhibitors are described, for example, in WO 03/035596, page 5, line 35 to page 10, line 4, to which reference is hereby made in the context of the present disclosure.

One or more polymerization inhibitors are preferably added to the reaction mixture selected from the group consisting of 2,6-di-tert-butyl-4-methylphenol, hydroquinone monomethyl ether, phenothiazine, triphenyl phosphite, diphenyl nylethen and 4-hydroxy-2,2,6, 6-tetramethyl-piperidine-N-oxyl.

In order to crosslink the prepolymers built up during the urethanization reaction, they can be reacted with a di- or polyamine (g) for a further molecular weight build-up. To this end, when the reaction of components (a) to (d) is substantially complete, i.e., the prepolymers obtained from the above reaction, i. for example, at least 95%, preferably at least 97% and particularly preferably at least 98%, for the reaction of the remaining free isocyanate groups with at least one, preferably exactly one di- or polyamine (g) implemented.

In a preferred embodiment, component (g) is added as soon as the NCO content (calculated at 42 g / mol) of the reaction mixture is not more than 1.5% by weight, more preferably not more than 1.2% by weight, very particularly preferably is not more than 1.0% by weight and more preferably not more than 0.9% by weight.

The NCO content should be at least 0.2% by weight, preferably at least 0.3% by weight, more preferably at least 0.4% by weight and most preferably at least 0.5% by weight. Diamines are, for example, 1, 2-diaminoethane, 1, 6-diaminohexane, piperazine, 2,5-dimethylpiperazine, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane (IPDA), 4,4'-di (aminocyclohexyl ) -methane, 1, 4-diaminocyclohexane, 1, 2- and 1, 3-diaminopropane, hydrazine, hydrazine hydrate, triamines are, for example, diethylenetriamine or tetramines such as N, N'-bis (3-aminopropyl) -1, 4 -diaminobutan. But there are also ketimines, as described in DE-B 27 25 589, ketazines, such as those of DE-B 28 11 148 and US-A 42 69 748, amine salts such as those in US-A 42 92 226 or oxazolidines, as described in DE-B 27 32 131 and US-A 41 92 937, into consideration. These are masked polyamines from which the corresponding polyamines are released in the presence of water as intermediates.

Preferred compounds (g), however, are di- or polyamines, which in turn carry a free or neutralized acid group, for example a carboxy or sulfonic acid group.

Particularly preferred are the ammonium or alkali salts of 6-amino-4-aza-hexanecarboxylic acid (N- (2'-carboxyethyl) ethylenediamine) and 5-amino-3-azapentanesulfonic acid (N- (2'-sulfoethyl) ethylenediamine) , Preferred their sodium, ammonium or potassium salts, particularly preferably their sodium salts.

Such products are described, for example, in EP 704469 A2, page 3, lines 47 to 49, for which the starting diamines mentioned there are 1,2-ethylenediamine, 1,3-propylenediamine, 1,4-butylenediamine, 1,5-pentylenediamine or 1 , 6-Hexylenediamine, in particular 1, 2-ethylenediamine offer.

As a rule, 0-10 mol% of di- or polyamine (g) (total of primary and secondary amino groups, based on isocyanate groups in (a)) is used, preferably 0-8 mol%, more preferably 1-7 and very particularly preferably 2 - 5 mol%.

Preferably, either at least one compound (g) or at least one compound (e) are present, more preferably at least one compound (g). Less preferably, both at least one compound (g) and at least one compound (e) are present.

The reaction can be regarded as terminated when the NCO value has reached at least 95%, preferably at least 97% and particularly preferably at least 98%, of the theoretical conversion value. If still unreacted isocyanate groups should be present, the reaction can be completed by reaction with the monoalcohol (f) under the above reaction conditions.

It is possible to disperse or dilute the reaction mixture in water after preparation.

The reaction can preferably be carried out in the presence of reactive diluent (B) which acts as a solvent both for the individual components and for the urethane (meth) acrylate (A) and is also a constituent of the coating composition later in the application.

For this purpose, the entire amount of the reactive diluent can already be introduced at the beginning of the reaction or added during the course of the reaction. However, it may also be useful to add part of the reactive diluent (B) only after completion of the reaction in order to further dilute the urethane (meth) acrylate (A).

Preferably, 30 to 100% of the total reactive diluent (B) used are already used in the reaction, particularly preferably 50 to 100%, very particularly preferably 70 to 100% and in particular 100%. The remainder may then be added after completion of the reaction.

The urethane (meth) acrylate (A) obtained according to the reaction procedure according to the invention, optionally dissolved in reactive diluent (B), can advantageously be used as or in radiation-curable coating compositions.

These coating compositions may contain further constituents:

If the curing of the coating compositions does not take place with electron beams, but by means of UV radiation, it is preferable to contain at least one photoinitiator which can initiate the polymerization of ethylenically unsaturated double bonds.

Photoinitiators may be, for example, photoinitiators known to those skilled in the art, e.g. those in "Advances in Polymer Science", Volume 14, Springer Berlin 1974 or in K.K. Dietliker, Chemistry and Technology of UV and EB Formulation for Coatings, Inks and Paints, Volume 3; Photoinitiators for Free Radical and Cationic Polymerization, P.K.T. Oldring (Eds), SITA Technology Ltd, London.

Suitable examples include mono- or Bisacylphosphinoxide, as described for example in EP-A 7 508, EP-A 57 474, DE-A 196 18 720, EP-A 495 751 or EP-A 615 980, for example, 2.4 , 6-trimethylbenzoyldiphenylphosphine oxide (Lucirin® TPO from BASF AG), ethyl 2,4,6-trimethylbenzoylphenylphosphinate (Lucirin® TPO L from BASF AG), bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide (Irgacure® 819 from Ciba Spezialitätenchemie), benzophenones, hydroxyacetophenones, phenylglyoxylic acid and their derivatives or mixtures of these photoinitiators. Examples which may be mentioned are benzophenone, acetophenone, acetonaphthoquinone, methyl ethyl ketone, valerophenone, hexanophenone, α-phenylbutyrophenone, p-morpholinopropiophenone, dibenzosuberone, 4-morpholinobenzophenone, 4-morpholinodeoxybenzoin, p-diacetylbenzene, 4-aminobenzophenone, 4'-methoxyacetophenone, β-methylanthraquinone, tert-butylanthraquinone, anthraquinone-carboxylic acid ester, benzaldehyde, α-tetralone, 9-acetylphenanthrene, 2-acetylphenanthrene, 10-thioxanthenone, 3-acetylphenanthrene, 3-acetylindole, 9-fluorenone, 1-indanone , 1, 3,4-triacetylbenzene, thioxanthen-9-one, xanthen-9-one, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropyltrioxanthone, 2,4-dichlorothioxanthone, benzoin , Benzoin isobutyl ether, chloroxanthenone, benzoin tetrahydropyranyl ether, benzoin methyl ether, benzoin ethyl ether, benzoin butyl ether, benzoin iso-propyl ether, 7-H-benzoin methyl ether, benz [de] anthracen-7-one, 1 -Naphthaldehyd, 4,4'-bis (dimethylamino) benzophenone, 4-phenylbenzophenone, 4-chloro-benzo phenone, Michler's ketone, 1-acetonaphthone, 2-acetonaphthone, 1-benzoylcyclohexan-1-ol, 2-hydroxy-2,2-dimethylacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy 2-phenylacetophenone, 1, 1-dichloroacetophenone, 1-hydroxyace- tophenone, acetophenone dimethyl ketal, o-methoxybenzophenone, triphenylphosphine, tri-o-tolylphosphine, benz [a] anthracene-7,12-dione, 2,2-diethoxyacetophenone, benzil ketals such as benzil dimethyl ketal, 2-methyl-1 - [4- (methylthio) phenyl] -2-morpholinopropan-1-one, anthraquinones such as 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone, 2 -Amylanthraquinone and 2,3-butanedione.

Also suitable are non-yellowing or slightly yellowing photoinitiators of the phenylglyoxalic acid ester type, as described in DE-A 198 26 712, DE-A 199 13 353 or WO 98/33761.

Typical mixtures include, for example, 2-hydroxy-2-methyl-1-phenylpropane-2-one and 1-hydroxycyclohexyl phenyl ketone, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide and 2 Hydroxy-2-methyl-1-phenyl-propan-1-one, benzophenone and 1-hydroxycyclohexyl phenyl ketone, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentyl phosphine oxide and 1-hydroxy cyclohexylphenylketone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide and 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2,4,6-trimethylbenzophenone and 4-methylbenzophenone or 2,4, 6-trimethylbenzophenone and 4-methylbenzophenone and 2,4,6-trimethylbenzoyldiphenylphosphine oxide.

Preferred among these photoinitiators are 2,4,6-trimethylbenzoyldiphenylphosphine oxide, ethyl 2,4,6-trimethylbenzoylphenylphosphinate, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, benzophenone, 1-benzoylcyclohexan-1-ol , 2-hydroxy-2,2-dimethylacetophenone and 2,2-dimethoxy-2-phenylacetophenone. The coating compositions preferably contain the photoinitiators in an amount of 0.05 to 10% by weight, particularly preferably 0.1 to 8% by weight, in particular 0.2 to 5% by weight, based on the total amount of the components ( a) to (f).

The coating compositions may contain further typical lacquer additives, such as leveling agents, defoamers, UV absorbers, dyes, pigments and / or fillers.

Suitable fillers include silicates, e.g. For example, by hydrolysis of silicon tetrachloride available silicates such as Aerosil® R 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® R brands Ciba Specialty Chemicals) and benzophenones. These may 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 derivatives thereof, eg. B. bis (2,2,6,6-tetra-methyl-4-piperidyl) sebacinate used. Stabilizers are usually used in amounts of 0.1 to 5.0 wt .-% based on the "solid" components contained in the preparation.

The coating compositions are particularly suitable for coating wood,

Wood materials and wood-containing substrates, such as fiberboard. Also conceivable is the coating of cellulose fibers, such as paper, cardboard or cardboard.

In particular, preference is given to those woods which are customarily used for parquet, for example oak, spruce, pine, beech, maple, chestnut, sycamore, ruby, ash, birch, pine and elm, but also cork.

In particular, the coating compositions are suitable as a precoating (primer, primer), preferably adhesion primer for wood, in particular for parquet. By using such coating compositions, the adhesion can be improved further coatings on this primer.

The substrates are coated by customary methods known to those skilled in the art, at least one coating composition being applied to the substrate to be coated in the desired thickness and the volatile constituents of the coating compositions being removed. If desired, this process can be repeated one or more times. The application to the substrate can in a known manner, for. B. by spraying, filling, doctoring, brushing, rolling, rolling or pouring done. The coating thickness is generally in a range of about 3 to 1000 g / m ² and preferably 10 to 200 g / m ² . Optionally, when multiple layers of the coating composition are applied one above the other, radiation curing takes place after each coating operation.

The radiation hardening takes place by the action of high-energy radiation, ie

UV radiation or daylight, preferably light of wavelength 250 to 600 nm or by irradiation with high-energy electrons (electron radiation, 150 to 300 keV). The radiation sources used are, for example, high-pressure mercury vapor lamps, lasers, pulsed lamps (flash light), halogen lamps or excimer radiators. The radiation dose for UV curing, which is usually sufficient for crosslinking, is in the range from 80 to 3000 mJ / cm ² .

The irradiation may optionally also in the absence of oxygen, for. B. under inert gas atmosphere, are performed. Suitable inert gases are preferably nitrogen, noble gases, carbon dioxide or combustion gases. Furthermore, the irradiation can be carried out by covering the coating composition with transparent media. Transparent media are z. As plastic films, glass or liquids, eg. B. water. Particular preference is given to irradiation in the manner described in DE-A1 199 57 900.

In a preferred method, the curing is carried out continuously by passing the treated with the coating composition substrate at a constant speed at a radiation source. For this purpose, it is necessary that the curing rate of the coating composition is sufficiently high.

This different time course of the curing can be made use of in particular when the coating of the article is followed by a processing step in which the film surface comes into direct contact with another object or is mechanically processed.

The advantage of the coating compositions is that it is possible to process the coated objects immediately after radiation curing because the surface no longer sticks. On the other hand, the dried film is still so flexible and stretchable that the article can still be deformed without the film flaking or cracking.

The invention will be further illustrated by the following non-limiting examples.

Examples

Example 1. In a three-necked flask with reflux condenser and stirrer 231 g Pluriol ^® E 600 were 165 g Pluriol ^® E 1000 (polyethylene glycols of average molecular weight 600 and 1000 g / mol, OH numbers 197 and 125, commercial products from BASF AG), 7, 6 g of dimethylolpropionic acid, 17.88 g of N-methyldiethanolamine, 46.44 g of 2-hydroxyethyl acrylate, 0.70 g of 2,6-di-tert-butyl-p-cresol and 0.35 g of methylhydroquinone at 60 ^° C. mixed. 0.30 g of dibutyltin dilaurate were added as catalyst to the well-mixed template. 222 g of isophorone diisocyanate were added dropwise to this mixture at 60 ° to 70 ^° C. within 50 minutes. It was then stirred for 2 hours at 60 to 65 ⁰ C internal temperature until the NCO value of the reaction mixture was 0.3%. Then, 19.5 g of 6-amino-4-aza-hexanecarboxylic acid (sodium salt) was added, and the reaction mixture was diluted with 200 g of water.

The solids of the urethane acrylate was 75% by weight. The double bond density of the solvent-free urethane acrylate was 0.56 mol / kg, and the viscosity 1 1, 5 Pa ^* s.

Example 2.

In a three-necked flask with reflux condenser and stirrer 330 g Pluriol E were ^® 600 (commercial product from BASF AG), 7.6 g of dimethylolpropionic acid, 17.88 g of N-methyldiethanolamine, 46.44 g 2-hydroxyethyl acrylate, 0.63 g of 2,6 -Di-tert-butyl-p-cresol and 0.32 methylhydroquinone at 60 ⁰ C mixed. 0.30 g of dibutyltin dilaurate were added as catalyst to the well-mixed template. At 60 to 70 ⁰ C 222 g of isophorone diisocyanate were added dropwise to this mixture within 40 minutes. It was then stirred for 4.5 hours at 60 to 65 ⁰ C internal temperature until the NCO value of the reaction mixture was 0.89%. Then, 19.5 g of 6-amino-4-aza-hexanecarboxylic acid (sodium salt) was added, and the reaction mixture was diluted with 200 g of water.

The solids of the urethane acrylate was 75%. The double bond density of the solvent-free urethane acrylate was 0.63 mol / kg, and the viscosity was 15.4 Pa ^* s.

Example 3.

In a three-necked flask with reflux condenser and stirrer 300 g Pluriol E were ^® 600 (commercial product from BASF AG), 7.6 g of dimethylolpropionic acid, N-8.94 g Methyldietha- ethanolamine, 75.4 g of 2-hydroxyethyl acrylate, 0.60 g of 2 , 6-di-tert-butyl-p-cresol and 0.30 methylhydroquinone at 60 ⁰ C mixed. 0.30 g of dibutyltin dilaurate were added as catalyst to the well-mixed template. 222 g of isophorone diisocyanate were added dropwise at 60 to 70 ^° C. within 45 minutes to this mixture. It was then stirred for 5 hours at 60 to 65 ⁰ C internal temperature until the NCO value of the reaction mixture was 0.77%. Then, 19.5 g of 6-amino-4-aza-hexanecarboxylic acid (sodium salt) was added and the reaction mixture was diluted with 183.3 g of water.

The solids of the urethane acrylate was 75%. The double bond density of the solvent-free urethane acrylate was 1.06 mol / kg, and the viscosity was 9.0 Pa ^* s. Example 4.

In a three-necked flask with reflux condenser and stirrer 330 g Pluriol E were ^® 600 (commercial product from BASF AG), 7.6 g of dimethylolpropionic acid, 8.94 g N-methyldiethanolamine, 75.4 g of 2-hydroxyethyl acrylate, 0.64 g of 2,6 -Di-tert-butyl-p-cresol and 0.32 methylhydroquinone at 60 ⁰ C mixed. 0.30 g of dibutyltin dilaurate were added as catalyst to the well-mixed template. 222 g of isophorone diisocyanate were added dropwise to this mixture at 60 ° to 70 ^° C. within 50 minutes. It was then stirred for 5 hours at 60 to 65 ⁰ C internal temperature until the NCO value of the reaction mixture was 0.5%. Then the reaction mixture was diluted with 214.3 g of water.

The solids of the urethane acrylate was 75%. The double bond density of the solvent-free urethane acrylate was 1.01 mol / kg, and the viscosity was 5.4 Pa ^* s.

Example 5.

In a three-necked flask with reflux condenser and stirrer 300 g Pluriol E were ^® 600 (commercial product from BASF AG), 7.6 g of dimethylolpropionic acid, 14.9 g of N-methyldiethanolamine, 75.4 g of 2-hydroxyethyl acrylate, 0.60 g of 2,6 -Di-tert-butyl-p-cresol and 0.30 methylhydroquinone at 60 ⁰ C mixed. 0.30 g of dibutyltin dilaurate were added as catalyst to the well-mixed template. 222 g of isophorone diisocyanate were added dropwise at 60 to 70 ^° C. within 45 minutes to this mixture. It was then stirred for 5.5 hours at 70 to 75 ⁰ C internal temperature until the NCO value of the reaction mixture was 0.30%. Then the reaction mixture was diluted with 206.3 g of water. The solids of the urethane acrylate was 75%. The double bond density of the solvent-free urethane acrylate was 1.05 mol / kg, and the viscosity 7.5 Pa ^* s.

Example 6.

In a three-necked flask with reflux condenser and stirrer, 270 g Pluriol® ^® E, 600 (commercial product from BASF AG), 7.6 g of dimethylolpropionic acid, 14.9 g of N-

Methyldiethanolamin, 87 g of 2-hydroxyethyl acrylate, 0.60 g of 2,6-di-tert-butyl-p-cresol and 0.30 methylhydroquinone at 60 ⁰ C mixed. 0.30 g of dibutyltin dilaurate were added as catalyst to the well-mixed template. 222 g of isophorone diisocyanate were added dropwise within 35 minutes to this mixture at 60 to 70 ⁰ C. It was then stirred for 6 hours at 70 to 75 ⁰ C internal temperature until the NCO value of the reaction mixture was 0.30%. Then, the reaction mixture was diluted with 200 g of water.

The solids of the urethane acrylate was 75%. The double bond density of the solvent-free urethane acrylate was 1.24 mol / kg, and the viscosity was 6.7 Pa ^* s.

Example 7. In a three-necked flask with reflux condenser and stirrer were 315 g of Pluriol ^® E 600, (commercial product of BASF AG), 7.6 g of dimethylolpropionic acid, 87 g of 2-hydroxyethyl acrylate, 0.64 g of 2,6-di-tert-butyl-p cresol and 0.32 g methylhydroquinone at 60 ⁰ C mixed. 0.30 g of dibutyltin dilaurate were added as catalyst to the well-mixed template. 222 g I- were at 60 to 70 ⁰ C sophorondiisocyanat added dropwise within 45 minutes to this mixture. It was then stirred for 5.5 hours at 70 to 75 ⁰ C internal temperature until the NCO value of the reaction mixture was 0.94%. Then, 19.5 g of 6-amino-4-aza-hexanecarboxylic acid (sodium salt) was added, and the reaction mixture was diluted with 200 g of water.

The solids of the urethane acrylate was 75%. The double bond density of the solvent-free urethane acrylate was 1.17 mol / kg and the viscosity was 5.1 Pa ^* s.

Example 8. A three-necked flask with reflux condenser and stirrer, 270 g Pluriol® ^® E, 600 (commercial product from BASF AG), 7.6 g of dimethylolpropionic acid, 8.94 g of N-methyl diethanolamine, 87 g 2-hydroxyethyl acrylate, 0.64 g of 2, 6-di-tert-butyl-p-cresol and 0.32 methylhydroquinone at 60 ⁰ C mixed. 0.30 g of dibutyltin dilaurate were added as catalyst to the well-mixed template. At 60 to 70 ⁰ C 222 g of isophorone diisocyanate were added dropwise to this mixture within 40 minutes. It was then stirred for 5.5 hours at 70 to 75 ⁰ C internal temperature until the NCO value of the reaction mixture was 0.74%. Then, 19.5 g of 6-amino-4-aza-hexanecarboxylic acid (sodium salt) was added, and after 5 minutes, the reaction mixture was diluted with 189.1 g of water. The solids of the urethane acrylate was 75%. The double bond density of the solvent-free urethane acrylate was 1.24 mol / kg, and the viscosity 7.5 Pa ^* s.

Example 9.

In a three-necked flask with reflux condenser and stirrer 300 g Pluriol E were ^® 600 (commercial product from BASF AG), 6.7 g of dimethylolpropionic acid, 14.9 g of N-

Methyldiethanolamin, 75.4 g of 2-hydroxyethyl acrylate, 0.63 g of 2,6-di-tert-butyl-p-cresol and 0.32 methylhydroquinone at 60 ⁰ C mixed. 0.33 g of dibutyltin dilaurate were added as catalyst to the thoroughly mixed stock. 233.1 g of isophorone diisocyanate were added dropwise within 50 minutes conces- to this mixture at 60 to 70 ⁰ C. It was then stirred for 7 hours at 75 ⁰ C internal temperature until the NCO value of the reaction mixture was 0.29%. Then, the addition of 1, 7 g of methanol. After 2 hours, the NCO content was 0.08% and the reaction mixture was diluted with 210 g of water. The solids of the urethane acrylate was 75%. The double bond density of the solvent-free urethane acrylate was 1.03 mol / kg and the viscosity was 9.6 Pa ^* s.

Example 10. In a three-necked flask with reflux condenser and stirrer 300 g Pluriol E were ^® 600 (commercial product from BASF AG), 6.7 g of dimethylolpropionic acid, 14.9 g of N-methyldiethanolamine, 75.4 g of 2-hydroxyethyl acrylate, 0.63 g of 2,6 -Di-tert-butyl-p-cresol and 0.32 methylhydroquinone at 60 ⁰ C mixed. 0.33 g of dibutyltin dilaurate were added as catalyst to the thoroughly mixed stock. To this mixture were added dropwise at 60 to 70 ⁰ C 244.2 g of isophorone diisocyanate within 50 minutes. It was then stirred for 7 hours at 75 ⁰ C internal temperature until the NCO value of the reaction mixture was 0.66%. Then, the addition of 4 g of methanol. After 4 hours, the NCO content was 0.1% and the reaction mixture was diluted with 213.7 g of water.

The solids of the urethane acrylate was 75%. The double bond density of the solvent-free urethane acrylate was 1.01 mol / kg, and the viscosity was 10.2 Pa ^* s.

EXAMPLE 1 1. In a three-necked flask with reflux condenser and stirrer 315 g Pluriol ^® E 600, (commercial product from BASF AG), 6.7 g of dimethylolpropionic acid, 87 g 2-hydroxyethyl acrylate, 0.64 g 2,6-di-tert were. Butyl p-cresol and 0.32 g of methylhydroquinone at 60 ⁰ C mixed. 0.30 g of dibutyltin dilaurate were added as catalyst to the well-mixed template. 233.1 g of isophorone diisocyanate were added dropwise within 45 minutes to this mixture at 60 to 70 ⁰ C. It was then stirred for 8 hours at 75 to 77 ⁰ C internal temperature until the NCO value of the reaction mixture was 0.68%. Then, 19.5 g of 6-amino-4-aza-hexanecarboxylic acid (sodium salt) was added 40% in water and the reaction mixture was diluted with 205 g of water. The solids of the urethane acrylate was 75%. The double bond density of the solvent-free urethane acrylate was 1.15 mol / kg, and the viscosity 7.7 Pa ^* s.

Example 12.

In a three-necked flask with reflux condenser and stirrer 315 g Pluriol ^® E 600, (commercial product from BASF AG), 6.7 g of dimethylolpropionic acid were 87 g of 2-

Hydroxyethyl acrylate, 0.64 g of 2,6-di-tert-butyl-p-cresol and 0.32 g of methylhydroquinone at 60 ⁰ C mixed. 0.30 g of dibutyltin dilaurate were added as catalyst to the well-mixed template. To this mixture were added dropwise at 60 to 70 ⁰ C 244.2 g of isophorone diisocyanate within 45 minutes. It was then stirred for 8 hours at 75 to 77 ⁰ C internal temperature until the NCO value of the reaction mixture was 1, 25%. Then, the addition of 3 g of methanol and after 2 hours, the NCO value was 0.71%. Subsequently, 19.5 g of 6-amino-4-aza-hexanecarboxylic acid (sodium salt) were metered in and, after 5 min, the reaction mixture was diluted with 208.5 g of water. The solids of the urethane acrylate was 75%. The double bond density of the solvent-free urethane acrylate was 1.13 mol / kg, and the viscosity was 8.8 Pa ^* s. Example 13.

In a three-necked flask with reflux condenser and stirrer 315 g Pluriol ^® E 600, (commercial product from BASF AG), 6.7 g of dimethylolpropionic acid were 87 g 2-hydroxyethyl acrylate, 0.64 g 2,6-di-tert-butyl-p Cresol, 0.32 g of methylhydroquinone and 160 g of acetone anhydrous at 60 ⁰ C mixed. 0.30 g of dibutyltin dilaurate were added as catalyst to the well-mixed template. To this mixture were added dropwise at 60 to 70 ⁰ C 233.1 g of isophorone diisocyanate within 40 minutes. It was then stirred for 15 hours at 75 to 77 ⁰ C internal temperature until the NCO value of the reaction mixture was 0.68%. Then, 19.5 g of 6-amino-4-aza-hexanecarboxylic acid (sodium salt) was added 40% and the reaction mixture was diluted with 205 g of water. Finally, the acetone was distilled off at 45 ° C and 100 mbar.

The solids of the urethane acrylate was 77%. The double bond density of the solvent-free urethane acrylate was 1.15 mol / kg, and the viscosity was 11. 2 Pa ^* s.

Example 14.

In a three-necked flask with reflux condenser and stirrer 315 g Pluriol ^® E 600, (commercial product from BASF AG), 6.7 g of dimethylolpropionic acid were 87 g 2-hydroxyethyl acrylate, 0.65 g 2,6-di-tert-butyl-p Cresol, 0.32 g of methylhydroquinone and 0.065 g of phenothiazine at 60 ⁰ C mixed. 0.30 g of dibutyltin dilaurate were added as catalyst to the well-mixed template. 233.1 g of isophorone diisocyanate were added dropwise within 50 minutes to this mixture at 60 to 70 ⁰ C. It was then stirred for 8 hours at 75 to 77 ⁰ C internal temperature until the NCO value of the reaction mixture was 0.95%. Then, 19.5 g of 6-amino-4-aza-hexanecarboxylic acid (sodium salt) was added 40% in water and then the reaction mixture was diluted with 205 g of water.

The solids of the urethane acrylate was 75%. The double bond density of the solvent-free urethane acrylate was 1.15 mol / kg, and the viscosity 7.7 Pa ^* s.

Example 15

In a three-necked flask with reflux condenser and stirrer 285 g Pluriol ^® E 600, (commercial product from BASF AG), 26.8 g of dimethylolpropionic acid were 63.8 g of 2-hydroxyethyl acrylate, 0.65 g 2,6-di-tert-butyl -p-cresol, 0.32 g methylhydroquinone, 0.65 g triphenyiphosphite and 0.33 g diphenylethene mixed at 60 ⁰ C. 0.30 g of dibutyltin dilaurate were added as the catalyst to the well-mixed starting material under nitrogen. 233.1 g of isophorone diisocyanate were added dropwise within 60 minutes to this mixture at 60 to 70 ⁰ C. It was then stirred for 7 hours at 75 to 80 ⁰ C internal temperature until the NCO value of the reaction mixture was 0.72%. The addition of 332 g of acetone was then anhydrous and then the addition of 19.5 g of 6-amino-4-aza-hexanecarboxylic acid (sodium salt) 40%, after a few minutes 72 g of sodium hydroxide were added. The reaction mixture was diluted with 270 g of water. Finally, the acetone was distilled off at 50 ⁰ C and 100 mbar.

The solids of the urethane acrylate was 71%. The double bond density of the solvent-free urethane acrylate was 0.9 mol / kg, and the viscosity was 10.8 Pa ^* s.

Comparative Example V1.

A commercially available mixture of a water-soluble unsaturated polyester acrylate and epoxy acrylate (Laromer® PE 22WN from BASF AG, Ludwigshafen) was mixed with a commercially available water-soluble epoxy acrylate (Laromer® LR 8765 from BASF AG, Ludwigshafen) 70 to 30 parts by weight The preparation of the radiation-curable Mass was carried out by intensive mixing of 100 parts by weight of this mixture with 4 parts by weight of a commercial photoinitiator Irgacure® 500 (1: 1 mixture of 1-hydroxycyclohexyl phenyl ketone and benzophenone) from Ciba Specialty Chemicals.

applications

The aqueous polyurethane preparations are applied as adhesive primer at 10 g / m ² on beech parquet and gelled in the UV system at a belt speed of 40m / min. Subsequently, a primer (Laromer® PE 56F (commercial mixture of polyester acrylate and epoxy acrylate from BASF AG, Ludwigshafen): 1,6-hexanediol diacrylate, 70:30) is applied with a thickness of 25 g / m ² and under the UV system gelled at a belt speed of 35 m / min. The second layer of the primer is cured twice under the UV system at a belt speed of 10 m / min. The coating is sanded with 400 grit sandpaper. The topcoat (Laromer LR8986 / LR 8967; 70:30, mixture of polyether acrylate and epoxy acrylate, commercial products of BASF AG) is introduced at a layer thickness of 10 g / m 2 and cured twice under the UV system at a belt speed of 10 m / min ,

The photoinitiator used was Irgacure® 500 from Ciba Spezialitätenchemie (1: 1 mixture of 1-hydroxycyclohexylphenyl ketone and benzophenone).

Coin-Test Examination: A coin is guided at a steep angle by pressing it over the parquet surface. If there is a loss of adhesion of the UV coating, this manifests itself in the so-called "white break" (a clearly recognizable scratch mark is formed). If the wood can be deformed without delamination of the UV coating one speaks of a very good Coin test. 1 = very good, 2 = good, 3 = medium.

The results are shown in Table 1. Table 1

2 3 4 5 6 7 8 9 10 11 12 13 14 V1

Example 1 66.6

Example 2 65.1

Example 3 66.1

Example 4 73.8

Example 5 69.8

Example 6 66

Example 7 71.2

Example 8 61.3

Example 9 66.8

Example 10 64.5

Example 11 69.7

Example 12 68.4

CO

Example 13 65 OO

Example 14 71.2

Laromer® PE 22WN 70

Laromer® LR 8765 30 lrgacure®500 1.5 1.5 1.5 1.7 1.6 1.5 1.6 1.4 1.5 1.5 1.6 1.5 1.5 1.6 2

Water 33.4 34.9 33.9 26.2 30.2 34 28.8 38.7 33.2 35.5 30.3 31.6 35 27.2 -

Solid only resin% 75 75 75 75 75 75 75 75 75 75 75 75 77.4 75

Viscosity-pure binder 11, 5 15.4 9 5.4 7.5 6.7 5.1 7.5 9.6 10.2 7.7 8.8 11.2 7.7

Viscosity Pas Varnishes 1.1 1.1 1.2 1.2 1.2 1.1 1.2 1.2 1.2 nm 1.2 nm 1.2 2 1.2

Solids% 50 48.8 49.6 55.4 52.4 49.5 53.4 46 50.1 48.4 52.3 51.3 50.1 53.4

Coin Test: Parquet Beech 3 3 2 2 1 2 1 2 2 1 1 1 1 1 2

Claims

claims 1. A process for the preparation of urethane (meth) acrylates (A) by reacting the components (a) at least one isocyanate having at least 2 isocyanate functions, (b) at least one polyalkylene oxide polyether having at least 2 hydroxy functions, (c) at least one hydroxy-functional (meth) acrylate having exactly one hydroxyl function and at least one (meth) acrylate function, (d) at least one compound having at least one isocyanate-reactive group and at least one acid function, (e) optionally at least one compound having at least one isocyanate-reactive group and at least one basic group for neutralization of the acid groups of component (d), (f) optionally at least one monoalcohol having exactly one hydroxyl function, (g) optionally at least one di- or polyamine, wherein the preparation of the urethane (meth) acrylate (A) can optionally be carried out in the presence of at least one reactive diluent (B) and / or optionally in the presence of at least one solvent, characterized in that components (b), (c), (d) and, if present, (e) are at least partly introduced from components (a) to (f) and the isocyanate (a ) is added. 2. The method according to claim 1, characterized in that it is the isocyanate (a) is a (cyclo) aliphatic diisocyanate. 3. The method according to any one of the preceding claims, characterized marked, that it is the component (b) is alkoxylated di- or polyols of Formula (Ia) to (Id),

(Ia) (Ib) (Ic)

(Id) wherein R ¹ and R ^{2 are} independently hydrogen or optionally Aryl, alkyl, aryloxy, alkyloxy, heteroatoms and / or heterocycles substituted Ci - Ciβ-alkyl, k, I, m, q independently of one another are each an integer from 1 to 15, preferably 1 to 10 and particularly preferably 1 to 7, and each Xi for i = 1 to k, 1 to I, 1 to m and 1 to q can be independently selected from the group -CH 2 -CH 2 -O-, -CH 2 -CH (CH 3) -O-, --CH ( CHs) -CH ₂ -O-, -CH ₂ -C (CHs) ₂ -O-, -C (CHs) 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 (CHs) -O- and -CH (CHs) -CH ₂ -O-, and more preferably -CH ₂ -CH ₂ -O-, where Ph is phenyl and Vin is vinyl. 4. The method according to any one of claims 1 or 2, characterized in that it is in the component (b) is a polyalkylene glycol of the formula

in which Xi for each i = 1 to n can be independently selected from the group consisting of -CH ₂ -CH ₂ -O-, -CH ₂ -CH (CHs) -O- and -CH (CHs) -CH ₂ -O - and more preferably -CH ₂ -CH ₂ -O- may be, and n can be an integer from 5 to 60, preferably from 7 to 50 and particularly preferably from 10 to 45. 5. The method according to any one of the preceding claims, characterized in that component (c) is selected from the group consisting of 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, 1,6-hexanediol mono (meth) acrylate, glycerol di (meth) acrylate, trimethylolpropane di (meth) acrylate, pentaerythritol tri (meth) acrylate, 2-hydroxyethyl (meth) acrylamide, 2-hydroxypropyl (meth) acrylamide and 3-hydroxypropyl (meth) acrylamide. 6. The method according to any one of the preceding claims, characterized in that a component (d) is present, selected from the group consisting of mercaptoacetic acid (thioglycolic acid), mercaptopropionic acid, mercaptosuccinic acid, hydroxyacetic acid, hydroxypropionic acid (lactic acid), hydrosuccinic, hydroxypivalic, dimethylolpropionic , Dimethylol butyric acid, hydroxydecanoic acid, hydroxydodecanoic acid, 12-hydroxystearic acid, hydroxyethanesulfonic acid, hydroxypropanesulfonic acid, Mercaptoethanesulfonic acid, mercaptopropanesulfonic acid, aminoethanesulfonic acid, aminopropanesulfonic acid, glycine (aminoacetic acid), N-cyclohexylaminoethanesulfonic acid, N-cyclohexylaminopropanesulfonic acid and iminodiacetic acid. 7. The method according to any one of the preceding claims, characterized in that the compound (e) is selected from the group consisting of diethanolamine, N-methyldiethanolamine and N-ethyldiethanolamine. 8. The method according to any one of the preceding claims, characterized in that the compound (g) is selected from the group consisting of 6-amino-4-aza-hexanecarboxylic acid and 5-amino-3-aza-pentanesulfonic acid and their ammonium or alkali metal salts , 9. The method according to any one of the preceding claims, characterized in that a compound (g) is added to the reaction mixture, if its NCO content (calculated at 42 g / mol) at least 0.2% by weight and not more than 1, 5 wt % is. 10. The method according to any one of the preceding claims, characterized in that the composition of the urethane (meth) acrylate (A) is selected as follows: (a) 100 mol% isocyanate functions, (b) 25 to 75 mol% of hydroxy functions (based on isocyanate functions in (a)), preferably 40 to 60 mol%, (c) 25 to 75 mol% of hydroxy functions (based on isocyanate functions in (a)), preferably 30 to 50 mol%, (d) 0 to 15 mol% of hydroxy functions (based on isocyanate functions in (a)), preferably 0 to 8 mol%, (e) 0 to 5 mol% isocyanate-reactive groups (based on isocyanate functions in (a)), (f) 0 to 5 mol% of hydroxy functions (based on isocyanate functions in (a)), with the proviso that the sum of the hydroxyl functions in components (b), (c), (d), (e) and (f) gives 100 mol% of hydroxy functions (based on isocyanate functions in (a)). 1 1. Use of reaction mixtures obtainable according to any one of the preceding claims in coating compositions for the coating of wood, wood-based materials, wood-containing substrates and cellulose fibers. 12. Use of reaction mixtures obtainable according to one of claims 1 to 10 in coating compositions for the primer coating of parquet.