HK1138613B

HK1138613B - Block-resistant, radiation-curablecoating systems based on high molecular mass, aqueous polyurethane dispersions

Info

Publication number: HK1138613B
Application number: HK10104285.4A
Authority: HK
Inventors: S‧萨默; J‧魏卡德; E‧吕曼
Original assignee: 科思创德国股份有限公司
Priority date: 2008-04-28
Filing date: 2010-04-30
Publication date: 2014-07-25

Description

Block-resistant, radiation-curable coating systems based on high molecular weight aqueous polyurethane dispersions

Cross Reference to Related Applications

The present application claims priority from german patent application No. 102008021151 filed 4/28/2008 according to 35 u.s.c. § 119 (a-d).

Background

The invention relates to block-resistant radiation-curable coating systems based on high molecular weight aqueous polyurethane dispersions, to a method for the production thereof, to the use of the coating systems as paints and/or adhesives, and to articles and substrates provided with these paints and/or adhesives.

Radiation-curable aqueous coating systems based on polyurethane polymers have been used for the coating of substrates, including wood, plastics and leather, which are distinguished by a number of beneficial properties, such as good chemical resistance and mechanical stability. It is particularly advantageous that the polyurethane outer coating has an ultra-fast curing rate with the aid of high-energy radiation by crosslinking of the ethylenic double bonds present in the polymer.

For many applications, for example in the case of wood/furniture coatings or plastic coatings, the initial physical drying plays an important role after evaporation of the water but before radiation curing takes place. Prior to radiation curing, the substrate had a film coating that was still tacky and unable to stack, even the slightest mechanical stress, such as that occurring in a paint shop during transport, left scratches on the coating, damaging it. Thus, in order to transport and store substrates that have been coated but not radiation cured, the coater may need to operate at high cost and under complex process conditions to accept out-of-specification products.

The systems known to date with good physical drying properties are still very sensitive before radiation curing. The reason is that the atmospheric humidity in the coating shops handling aqueous adhesives is usually high, resulting in films which have not been radiation-cured starting to swell and become soft. Thus resulting in the blocking-resistant coating no longer having advantages such as ease of handling and stack storage.

It is desirable to obtain coatings that, after physical drying, have blocking resistance that is sufficiently water resistant to maintain blocking resistance even at high atmospheric humidity, or have some degree of blocking resistance in the case of incomplete radiation curing, such as in the case of complex shaped articles, such as chairs. The use of such coating systems will increase the efficiency of the coating operation and thus reduce the coating costs.

The current requirements for coating systems are multifaceted. Therefore, it is not sufficient if the radiation-curable coating systems have antiblocking properties only after physical drying, but the films obtained are also required to have high chemical stability and good mechanical strength after radiation curing.

EP-A753531 describes polyurethane acrylate dispersions based on hydroxyl-containing polyester acrylates and polyepoxide acrylates. Although the films described in this document can be physically dried, they have poor water resistance prior to radiation curing and also have poor solvent resistance after radiation curing. In this application, alcohols or amines having a functionality of greater than or equal to 3 are intentionally not used to form high molecular weight polyurethane acrylates to improve antiblocking properties.

EP-A942022 describes polyurethane acrylate dispersions based on hydroxyl-containing polyesters, polyethers or polyurethane acrylates and polyepoxide acrylates. As described herein, the coating system forms a physically dry clear coating, but has insufficient water resistance prior to radiation curing. Furthermore, the use of polyepoxyacrylates leads to poor weathering stability due to the aromatic component. The use of polyepoxy acrylates also leads to the formation of brittle films after radiation curing and thus to poor adhesion to plastic substrates.

EP-A872502 describes radiation-curable aqueous polyurethane dispersions based on hydroxyl-containing polyester acrylates and polyether acrylates. The coating system forms a physically dryable but poorly antiblocked film. Solvent resistance is likewise insufficient. There is no description in this document of the deliberate use of alcohols or amines having a functionality of greater than or equal to 3 for improving the antiblocking properties.

It is an object of the present invention to provide coating systems based on radiation-curable aqueous polyurethane dispersions which, after physical drying and before radiation curing, provide coatings having good blocking resistance. These coatings have sufficient water resistance even without radiation curing and therefore retain antiblocking properties even at high atmospheric humidity. Furthermore, after radiation curing, the film coating has mechanical strength and high chemical resistance.

This object is achieved by preparing the polyurethane present in the dispersion using an amine having a functionality of greater than or equal to 3 and an alcohol.

Summary of The Invention

Accordingly, the present invention provides a coating system based on a radiation curable aqueous polyurethane dispersion, which system comprises:

I) polyurethanes obtained from A), B), C), D), E) and F):

A)40-80 wt% of a hydroxyl-containing component comprising:

A1) 10 to 80% by weight, based on the total weight of components (A) to (F) and (II), of one or more hydroxyl-containing prepolymers selected from polyester (meth) acrylates or polyether (meth) acrylates having an OH number of 5 to 300 mg KOH/g solid and containing groups which, after exposure to high-energy radiation, undergo polymerization with ethylenically unsaturated double bonds,

A2) from 0 to 50% by weight, based on the total weight of components (A) to (F) and (II), of one or more (meth) acrylate group-containing monomeric alcohols having an OH number of from 35 to 1000 mg KOH/g solid,

B) from 0.1 to 20% by weight, based on the total weight of components (A) to (F) and (II), of one or more compounds reactive toward isocyanate groups, which contain groups of the nonionic, ionic or ionic group-forming type and have a dispersing action on polyurethane dispersions,

C)0.1 to 30% by weight, based on the total weight of components (a) to (F) and (II), of a hydroxyl-and/or amine-containing component comprising:

C1) 0.1 to 10% by weight, based on the total weight of components (A) to (F) and (II), of a hydroxy-and/or amine-functional monomer compound having a functionality of 3 to 6 and a molecular weight of 92 to 254 g/mol,

and/or

C2) 0.1 to 20% by weight, based on the total weight of components (A) to (F) and (II), of hydroxy-and/or amine-functional polyesters, C2, C3 and/or C4 polyethers and polyether esters having a functionality of 2.3 to 4.0 and a molecular weight of 238-4000 g/mol,

D) 0 to 30% by weight, based on the total weight of components (a) to (F) and (II), of a hydroxy-functional compound selected from the group consisting of: mono-and/or di-alcohols, all having a molecular weight in the range of 32 to 118 g/mol; polyesters, polycarbonates, C2, C3 and/or C4 polyethers, polyether esters and polycarbonate polyesters, all having a functionality of 1.0 to 2.0 and molecular weights in the range of 32 to 4000 g/mol,

E) 0.1 to 10 wt.%, based on the total weight of components (A) to (F) and (II), of a monoamine, diamine and/or difunctional aminoalcohol,

F) from 10 to 50% by weight, based on the total weight of components (A) to (F) and (II), of one or more polyisocyanates,

with the proviso that no polyepoxide (meth) acrylate is used in the synthesis of (I);

and

II)0 to 40% by weight of an oligomeric (meth) acrylate from the group of components (A1) having a double bond density of more than 2.0 mol double bonds per kg solid and capable of polymerization with ethylenically unsaturated compounds after exposure to high-energy radiation,

the sum of the percentages by weight of components (A) to (F) and of component (II) being 100% by weight, the weight-average molecular weight MW of the mixture of (I) and (II) present in the coating system being greater than 50000-3000000 g/mol.

The present invention also provides a process for preparing the coating system of the present invention, comprising the steps of:

i) components A) to D) are reacted with component F) to form a polyurethane prepolymer,

II) mixing component II with the reaction product of step i), and

iii) dispersing the mixture obtained after step ii) in water to form an aqueous polyurethane dispersion,

if appropriate, the (potentially) ionic groups are introduced, component B) is at least partially neutralized before, during or after mixing with component II or before, during or after dispersion, and

the polyurethane prepolymer is reacted with component E at any possible time after step i).

Detailed description of the preferred embodiments

The invention is suitably carried out as follows: introducing the components (A), (B), (C) and (D) as initial charge into a reactor, if appropriate diluted with a water-miscible, but isocyanate-group-inert solvent, heating to a temperature of from 30 to 80 ℃ and, if appropriate, adding an isocyanate addition reaction catalyst to the mixture of the compounds (A), (B), (C) and (D) before reaction with the polyisocyanate (F), the molar ratio of isocyanate-reactive groups in (A), (B), (C) and (D) to the isocyanate groups (F) being from 1: 0,8 to 1: 2,5, and dissolving the polyurethane obtained according to step i) together with the oligo (meth) acrylate (II) in acetone to give an oligo (meth) acrylate/acetone solution; this solution is introduced into the dispersion water containing the amine(s) (E) according to step iii) with vigorous stirring or, conversely, the dispersion water/amine mixture is added to the polyurethane oligo (meth) acrylate/acetone solution. If appropriate, acetone is subsequently distilled off.

The present invention also provides radiation-curable coating systems having blocking resistance after physical drying, obtainable by the process according to the invention.

If the degree of neutralization of the acids and/or bases introduced by component (B) is from 50% to 125%, the coating systems obtained by the process according to the invention are preferred. A degree of neutralization of more than 100% means that the neutralization is carried out with an excess of base or acid, respectively, compared to the acid or base bound to the polymer.

The coating systems obtained by the process according to the invention are preferred if the reaction of the residual free isocyanate groups of the prepolymer with component (E) is carried out to an extent of from 35% to 150%. When an amine (E) is used in a stoichiometric deficiency, the residual free isocyanate groups react with water and are slowly consumed. When an excess of amine (E) is used, there will no longer be any unreacted isocyanate groups, giving an amine-functional polyurethane.

The coating system obtained according to the process of the invention is preferred if the following components are present: 0.1 to 10 wt.% of a hydroxy-and/or amine-functional compound having a functionality of 3 to 6 and a molecular weight of 92 to 254 g/mol,

and/or

0.1 to 20% by weight of hydroxyl-and/or amine-functional polyesters, polycarbonates, C2, C3 and/or C4 polyethers, polyether esters and polycarbonate polyesters, with a functionality of 2.5 to 4.0 and a molecular weight of 238-4000 g/mol.

The coating systems obtained according to the process of the invention are preferred if the weight average molecular weight MW of the mixture of (I) and (II) is preferably 100000-2000000 g/mol, more preferably 150000-1000000 g/mol.

The coating systems obtained by the process according to the invention are preferred if the reaction of the polyurethane prepolymer with component (E) in acetone solution is carried out before or after the addition of component (II).

The coating systems obtained by the process according to the invention are preferred if the aqueous polyurethane dispersions additionally comprise at least one initiator and, if appropriate, auxiliaries and additives and are cured under high-energy radiation.

The coating systems obtained by the process according to the invention are preferred if the aqueous polyurethane dispersions contain less than 5% by weight of organic solvents.

The invention also provides the use of the coating systems obtained by the process according to the invention for producing adhesives and/or antiblocking transparent clear or pigmented lacquers.

The invention also provides a transparent, blocking-resistant clear varnish or pigmented paint comprising a coating system obtained by the process according to the invention.

The invention also provides binders comprising the coating systems obtained according to the process of the invention.

The invention also provides the use of a hard, transparent clear varnish or lacquer comprising a coating system obtained according to the process of the invention for producing a coated substrate.

The invention also provides the use of a binder comprising a coating system obtained according to the process of the invention for the production of an article composed of at least two or more materials.

The present invention also provides a substrate comprising a transparent anti-blocking varnish or lacquer comprising a coating system obtained according to the process of the present invention.

Substrates having a blocking-resistant transparent clear or pigmented varnish comprising a coating system obtained according to the process of the invention are preferred if the substrate is selected from wood, wood-based materials, furniture, wood-based floors, doors, window frames, metal articles, plastics, paper, cardboard, cork, mineral substrates, textiles or leather.

The invention also provides an article comprising a binder comprising a coating system obtained according to the process of the invention.

An article having a binder comprising a coating system obtained according to the process of the invention is preferred if the article is composed of at least two similar and/or different materials selected from the group consisting of: wood, wood-based materials, furniture, wood flooring, doors, window frames, metal, plastic, paper, cardboard, cork or leather.

Component (a) comprises component (a1) and optionally component (a 2).

Component (a1) comprises oligomers and polymers containing saturated groups. These unsaturated group-containing oligomers and polymers are selected from the group consisting of: polyester (meth) acrylates, polyether (meth) acrylates, polyetherester (meth) acrylates, unsaturated polyesters comprising allyl ether structural units, and combinations of said compounds.

Among the polyester (meth) acrylates which can be used as component (A1) are hydroxyl-containing polyester (meth) acrylates having an OH number of from 15 to 300 mg KOH/g solids, preferably from 60 to 200 mg KOH/g solids. In the preparation of the hydroxy-functional polyester (meth) acrylate (a1), a total of 7 sets of monomer components can be used:

the first group (a) comprises alkanediols (alkanediol) or diols (diol) or mixtures thereof. The alkanediol has a molecular weight of 62 to 286 g/mol. The alkylene glycol is preferably selected from the group consisting of: ethylene glycol, 1, 2-and 1, 3-propanediol, 1,2-, 1, 3-and 1, 4-butanediol, 1, 5-pentanediol, 1, 6-hexanediol, neopentyl glycol, cyclohexane-1, 4-dimethanol, 1, 2-and 1, 4-cyclohexanediol, 2-ethyl-2-butylpropanediol. Preferred diols are ether oxygen-containing diols, such as diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, polyethylene glycols, polypropylene glycols or polybutylene glycols having molecular weights of 200-. The reaction products of the above diols with epsilon-caprolactone or other lactones may also be used as diols.

The second group (b) comprises alcohols having a functionality of greater than or equal to 3 and a molecular weight of 92 to 254 g/mol, and/or polyethers prepared starting from these alcohols. Particularly preferred alcohols having a functionality of greater than or equal to 3 are glycerol, trimethylolpropane, pentaerythritol, dipentaerythritol and sorbitol. One particularly preferred polyether is the reaction product of 1 mole trimethylolpropane and 4 moles ethylene oxide.

The third group (c) comprises monoalcohols. Particularly preferred monoalcohols are selected from the following group: ethanol, 1-and 2-propanol, 1-and 2-butanol, 1-hexanol, 2-ethylhexanol, cyclohexanol and benzyl alcohol.

The fourth group (d) comprises dicarboxylic acids having a molecular weight of 104-. Preferred dicarboxylic acids and their anhydrides are selected from the group consisting of: phthalic acid, phthalic anhydride, isophthalic acid, tetrahydrophthalic anhydride, hexahydrophthalic acid, hexahydrophthalic anhydride, cyclohexanedicarboxylic acid, maleic anhydride, fumaric acid, malonic acid, succinic anhydride, glutaric acid, adipic acid, pimelic acid, suberic acid, sebacic acid, dodecanedioic acid, hydrogenated dimers of the fatty acids listed in the sixth group (f).

The fifth group (e) comprises trimellitic acid or trimellitic anhydride.

The sixth group (f) includes monocarboxylic acids selected from benzoic acid, cyclohexanecarboxylic acid, 2-ethylhexanoic acid, caproic acid, caprylic acid, capric acid, lauric acid, and natural and synthetic fatty acids selected from lauric acid, myristic acid, palmitic acid, margaric acid, stearic acid, behenic acid, cerotic acid, palmitoleic acid, oleic acid, eicosenoic acid (icosenic acid), linoleic acid, linolenic acid, and arachidonic acid.

The seventh group (g) comprises acrylic acid, methacrylic acid and/or dimeric acrylic acid.

Suitable hydroxyl-containing polyester (meth) acrylates (A1) comprise the reaction product of at least one component selected from groups (a) or (b) with at least one component selected from groups (d) or (e) and at least one component selected from group (g).

Particularly preferred components of group (a) are selected from the following group: ethylene glycol, 1, 2-and 1, 3-propanediol, 1, 4-butanediol, 1, 6-hexanediol, neopentyl glycol, cyclohexane-1, 4-dimethanol, 1, 2-and 1, 4-cyclohexanediol, 2-ethyl-2-butylpropanediol, an ether oxygen-containing diol selected from the group consisting of diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol and tripropylene glycol. Preferred components of group (b) are selected from the group consisting of: glycerol, trimethylolpropane, pentaerythritol or the reaction product of 1 mole trimethylolpropane with 4 moles of ethylene oxide. Particularly preferred components of groups (d) and (e) are selected from the following group: phthalic anhydride, isophthalic acid, tetrahydrophthalic anhydride, hexahydrophthalic acid, hexahydrophthalic anhydride, maleic anhydride, fumaric acid, succinic anhydride, glutaric acid, adipic acid, dodecanedioic acid, hydrogenated dimers of the fatty acids listed in group (f), trimellitic anhydride. A preferred component of group (g) is acrylic acid.

If desired, it is also possible to introduce groups having a known dispersing action into these polyester (meth) acrylates. For example, as the alcohol component, polyethylene glycol and/or methoxypolyethylene glycol may be used in proportion. As the compound, polyethylene glycol, polypropylene glycol and block copolymers thereof prepared from alcohols, and monomethyl ethers of these polyglycols can be used. Particularly suitable is polyethylene glycol monomethyl ether having a molecular weight of 500-1500 g/mol.

After esterification, it is also possible to react some of the remaining unesterified free carboxyl groups, in particular those of (meth) acrylic acid, with mono-, di-or polyepoxides. Preferred epoxides are glycidyl ethers of monomeric, oligomeric or polymeric bisphenol a, bisphenol F, hexanediol and/or butanediol or their ethoxylated and/or propoxylated derivatives. This reaction is particularly useful for increasing the OH number of polyester (meth) acrylates, since the epoxide/acid reaction in each case generates one OH group. The acid number of the product obtained is from 0 to 20 mg KOH/g, preferably from 0 to 10 mg KOH/g, more preferably from 0 to 5 mg KOH/g solid. The reaction is preferably carried out under catalysis of a catalyst, examples of which are triphenylphosphine, thiodiglycol, ammonium halides and/or phosphonium halides and/or zirconium compounds or tin compounds, for example tin (II) ethylhexanoate.

The preparation of polyester (meth) acrylates is described in the following documents: DE-A4040290, page 3, line 25 to page 6, line 24; DE-A3316592, page 5, line 14 to page 11, line 30; t. T.Oldring (eds.), Chemistry & Technology of UV & EB formulations for Coatings, Inks & Paints, Vol.2, 1991, SITA Technology, London, p.123-135.

Also suitable as component (A1) are hydroxyl-containing polyether (meth) acrylates obtained by reacting acrylic acid and/or methacrylic acid with polyethers. The polyether is selected from the group consisting of: homopolymers, copolymers or block copolymers of ethylene oxide, propylene oxide and/or tetrahydrofuran on any desired hydroxyl-and/or amine-functional starter molecule selected from the group consisting of trimethylolpropane, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, glycerol, pentaerythritol, neopentyl glycol, butanediol and hexanediol.

In addition to the unsaturated compounds, component (A1) preferably also contains NCO-reactive compounds, more preferably hydroxyl groups. Through these hydroxyl groups, component (a1) is partially or completely incorporated into the polyurethane framework.

Preferred components (a1) are compounds selected from the group consisting of: polyester (meth) acrylates, polyether (meth) acrylates and polyether ester (meth) acrylates having hydroxyl groups and unsaturated groups.

Particularly preferred as component (A1) are hydroxy-functional polyester (meth) acrylates and polyether (meth) acrylates.

In addition, the compound of component (a1) may be used alone, or a combination of component (a1) and the following compound (a2) may be used.

Component (A2) comprises one or more monomeric alcohols which contain (meth) acrylate groups and have an OH number of from 35 to 1000 mg KOH/g, preferably an OH number of 130 and 966 mg KOH/g of solid. Such (meth) acrylate group-containing alcohols are selected from the group consisting of: 2-hydroxyethyl (meth) acrylate, caprolactone-extended modifications of 2-hydroxyethyl (meth) acrylate, e.g. Pemcure12A (cogis, germany), 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 3-hydroxy-2, 2-dimethylpropyl (meth) acrylate, polyol esters of average monohydroxy-functional di-, tri-, tetra-or penta- (meth) acrylic acids, such as trimethylolpropane, glycerol, pentaerythritol, ditrimethylolpropane, dipentaerythritol, ethoxylated, propoxylated or alkoxylated trimethylolpropane, glycerol, pentaerythritol, ditrimethylolpropane, dipentaerythritol or technical-grade mixtures thereof, (a2) incorporation into the adduct of components (a), (B), (C), (D) and (F) proceeds via the still free hydroxyl functions.

Furthermore, an alcohol obtained by reacting an acid having a double bond with an optionally double bond-containing monomeric epoxy compound may also be used as component (A2). Preferred reaction products are selected from the reaction products of (meth) acrylic acid with glycidyl (meth) acrylate or with glycidyl esters of saturated mono-tertiary carboxylic acids. The saturated mono-tertiary carboxylic acid is selected from the group consisting of: 2, 2-dimethylbutyric acid, ethylmethylbutanoic acid, ethylmethylpentanoic acid, ethylmethylhexanoic acid, ethylmethylheptanoic acid, and ethylmethyloctanoic acid.

Particularly preferred as component A2 are 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, pentaerythritol triacrylate, dipentaerythritol pentaacrylate, the adduct of glycidyl ethylmethylheptanoate with (meth) acrylic acid, and technical-grade mixtures thereof.

Component (B) comprises one or more compounds which are reactive toward isocyanate groups and have a dispersing action on the aqueous polyurethane dispersion. The compounds which are reactive toward isocyanate groups and have a dispersing action are acids, bases, ionic compounds and compounds containing ether groups. Preferred acids and bases have groups selected from hydroxyl, amino and mercapto groups, by means of which the compounds are incorporated into the reaction products of components (A), (C), (D) and (F), their isocyanate-reactive groups being subsequently converted into corresponding groups having a dispersing action, selected from sulfonium salts, ammonium salts, carboxylic acid salts and sulfonic acid salts. Particularly preferred acids, bases and ionic compounds are selected from the group consisting of: monohydroxy-and dihydroxycarboxylic acids, monoamino-and diaminocarboxylic acids, monohydroxy-and dihydroxysulfonic acids, monoamino-and diaminosulfonic acids, monohydroxy-and dihydroxyphosphonic acids, monoamino-and diaminophosphonic acids and their salts, for example dimethylolpropionic acid, dimethylolbutyric acid, hydroxypivalic acid, N- (2-aminoethyl) -alanine, 2- (2-aminoethylamino) ethanesulfonic acid, ethylenediamine propyl-or-butylsulfonic acid, 1, 2-or 1, 3-propylenediamineethylsulfonic acid, malic acid, citric acid, glycolic acid, lactic acid, glycine, alanine, taurine, lysine, 3, 5-diaminobenzoic acid, the adduct of isophoronediamine (1-amino-3, 3, 5-trimethyl-5-aminomethylcyclohexane or IPDA) with acrylic acid (EP-A916647, example 1) and their alkali metal and/or ammonium salts; adducts of sodium bisulfite and but-2-ene-1, 4-diol, polyether sulfonates, 2-butenediol, and NaHSO₃Propoxylated adducts of (A) as described, for example, in DE-A2446440 (pages 5-9, general formulae 1-1)11) As described in (1) and N-methyldiethanolamine and compounds having carboxyl or carboxylate and/or sulfonate and/or ammonium groups. Particularly preferred ionic compounds are compounds which contain carboxyl and/or sulfonate groups as ionic groups, for example salts of 2- (2-aminoethylamino) ethanesulfonic acid or of the adduct of isophoronediamine and acrylic acid (EP 916647A 1, example 1), and also salts of dimethylolpropionic acid.

Preferred ether group-containing compounds are selected from the group consisting of polyethylene glycol prepared from alcohols, polypropylene glycol and block copolymers thereof, and monomethyl ethers of these polyglycols. Preferred are polyethers of linear structure having a functionality of 1 to 3, and also preferred are compounds of the general formula (I):

in the formula:

R¹and R²Each independently of the other represents a divalent aliphatic, cycloaliphatic or aromatic radical having from 1 to 18 carbon atoms which may contain oxygen and/or nitrogen atoms, R³Is an alkoxy-terminated polyethylene oxide group.

Preferred polyethers are selected from the group consisting of: monofunctional polyalkylene oxide polyether alcohols having an average of from 5 to 70, preferably from 7 to 55, ethylene oxide units per molecule, for example of the type obtained by alkoxylation of suitable starter molecules by customary methods, as described, for example, in Ullmanns encyclopedie der technischen Chemie, 4 th edition, volume 19, Verlag Chemie, Weinheim, pages 31 to 38.

Preferred starter molecules for this purpose are selected from the group consisting of: saturated monoalcohols, such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, the isomeric pentanols, hexanols, octanols and nonanols, n-decanol, n-dodecanol, n-tetradecanol, n-hexadecanol, n-octadecanol, cyclohexanol, the isomeric methylcyclohexanols or hydroxymethylcyclohexanes, 3-ethyl-3-hydroxymethyloxetane or tetrahydrofurfuryl alcohol, diethylene glycol monoalkyl ethers, such as diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether; unsaturated alcohols, such as allyl alcohol, 1-dimethylallyl alcohol or oleyl alcohol; aromatic alcohols, such as phenol, the isomeric cresols or methoxyphenols; araliphatic alcohols, such as benzyl alcohol, anisyl alcohol or cinnamyl alcohol; secondary monoamines, such as dimethylamine, diethylamine, dipropylamine, diisopropylamine, dibutylamine, bis (2-ethylhexyl) amine, N-methyl-and N-ethylcyclohexylamine or dicyclohexylamine; and heterocyclic secondary amines, such as morpholine, pyrrolidine, piperidine or 1H-pyrazole. Particularly preferred starter molecules are selected from the group consisting of: saturated monoalcohols, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether and diethylene glycol monobutyl ether. Particular preference is given to using diethylene glycol monomethyl ether, diethylene glycol monoethyl ether or diethylene glycol monobutyl ether.

Alkylene oxides suitable for the alkoxylation reaction are ethylene oxide and propylene oxide, which can be used in the alkoxylation reaction in any order or in mixtures.

The polyalkylene oxide polyether alcohols may be pure polyethylene oxide polyethers or also mixed polyalkylene oxide polyethers in which at least 30 mol%, preferably at least 40 mol%, of the alkylene oxide units consist of ethylene oxide units. Preferred nonionic compounds are monofunctional mixed polyalkylene oxide polyethers which contain at least 40 mol% ethylene oxide units and not more than 60 mol% propylene oxide units.

The above acids can be converted into the corresponding salts by reaction with neutralizing agents such as triethylamine, ethyldiisopropylamine, dimethylcyclohexylamine, dimethylethanolamine, ammonia, N-ethylmorpholine, LiOH, NaOH and/or KOH. In this case, the degree of neutralization is 50% to 125%.

Component (C) includes component (C1) and/or component (C2).

Component (C1) is preferably selected from the group consisting of: aliphatic or cycloaliphatic triols, tetraols and hexaols and triamines and tetraamines having from 3 to 10 carbon atoms. Preferred triols are glycerol, trimethylolethane, trimethylolpropane and trimethylolbutane. Preferred tetrols are selected from pentaerythritol and ditrimethylol propane. Preferred hexaols are dipentaerythritol, sorbitol and hexoses, such as glucose and fructose. Preferred triamines and tetramines are diethylenetriamine and triethylenetetramine.

Particularly preferred triols are glycerol and trimethylolpropane, particularly preferred tetrols are ditrimethylolpropane and pentaerythritol, and particularly preferred hexols are dipentaerythritol.

Component (C2) comprises hydroxyl-and/or amine-functional polyesters, C2, C3 and/or C4 polyethers and polyether esters having a functionality of from 2.3 to 4.0 and a molecular weight of 238-4000 g/mol.

Preferred hydroxy-functional polyesterols are polyesterols based on aliphatic, cycloaliphatic and/or aromatic monocarboxylic, dicarboxylic, tricarboxylic and/or polycarboxylic acids (polycarboxylic acids) and monoalcohols, diols, triols and/or polyols. Particularly preferred polyesterols are selected from the group consisting of the reaction products of adipic acid, isophthalic acid and phthalic anhydride with trimethylolpropane, glycerol, pentaerythritol, hexanediol, butanediol, diethylene glycol, monoethylene glycol or neopentyl glycol or mixtures of the abovementioned diols, having molecular weights of 300-4000, preferably 300-2500.

Preferred hydroxy-functional polyether alcohols are selected from: a reaction product obtained by polymerization of a cyclic ether, or a product obtained by reaction of an alkylene oxide with a trifunctional or hexafunctional starter molecule mentioned in (C1). Particularly preferred are polyethylene glycol and/or polypropylene glycol having an average molecular weight of 238-4000 g/mol and polytetrahydrofuran having an average molecular weight of 500-4000 g/mol, preferably 800-3000 g/mol.

Component (D) comprises a hydroxy-functional compound selected from the group consisting of: mono-and/or di-alcohols, all having a molecular weight in the range of 32 to 118 g/mol; hydroxyl-functional polyesters, polycarbonates, polyurethanes, C2, C3 and/or C4 polyethers, polyether esters and polycarbonate polyesters, all having a functionality of from 1.0 to 2.0 and molecular weights in the range from 300 to 4000 g/mol.

Preferred diols of component (D) are selected from the following group: aliphatic, araliphatic or cycloaliphatic monoalcohols and/or diols containing 2 to 20 carbon atoms. The monoalcohol is preferably selected from the group consisting of: methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 2-propanol, 2-butanol and 2-ethylhexanol. Preferred diols are selected from the group consisting of: ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, 1, 2-propanediol, 1, 3-propanediol, 1, 4-butanediol, neopentyl glycol, 2-ethyl-2-butylpropanediol, trimethylpentanediol, 1, 3-butanediol, 1, 4-cyclohexanedimethanol, 1, 6-hexanediol, 1, 2-and 1, 4-cyclohexanediol, hydrogenated bisphenol A (2, 2-bis (4-hydroxycyclohexyl) propane), 2-dimethyl-3-hydroxypropyl 2, 2-dimethyl-3-hydroxypropionate. Particularly preferred are 1, 4-butanediol, 1, 4-cyclohexanedimethanol and 1, 6-hexanediol.

Preferred oligomers and/or higher molecular weight diols or aminoalcohols having a number average molecular weight of 300-4000 g/mol, preferably 500-2500 g/mol, for example hydroxy-functional oligomers and/or polymers such as hydroxy-functional polyesters, polycarbonates, polyurethanes, C2, C3 and/or C4 polyethers, polyether esters or polycarbonate polyesters, have an average hydroxy functionality of from 1.0 to 2.0.

Preferred hydroxy-functional polyesterols are polyesterols based on aliphatic, cycloaliphatic and/or aromatic dicarboxylic acids and diols, and also polyesterols based on lactones. Particularly preferred polyesterols are selected from the group consisting of: adipic acid, isophthalic acid and phthalic anhydride with hexanediol, butanediol, diethylene glycol, monoethylene glycol or neopentyl glycol or mixtures of the abovementioned diols, and having a molecular weight of 500-.

Preferred hydroxy-functional polyether alcohols are selected from the group consisting of: a reaction product obtained by polymerization of a cyclic ether, or a product obtained by reaction of an alkylene oxide with a starter molecule. Particularly preferred are polyethylene glycol and/or polypropylene glycol having an average molecular weight of 500-4000 g/mol and polytetrahydrofuran having an average molecular weight of 500-4000 g/mol, preferably 800-3000 g/mol.

Preferred hydroxy-functional polycarbonates are hydroxy-terminated polycarbonates obtained by reaction of diols or other lactone-modified diols or bisphenols selected from bisphenol A, polycarbonates obtained by phosgene or carbonic diesters, such as diphenyl carbonate or dimethyl carbonate, polymeric carbonates of 1, 6-hexanediol having an average molecular weight of 500-4000 g/mol, and the product carbonates of the reaction of 1, 6-hexanediol with epsilon-caprolactone in a molar ratio of 1 to 0.1. Particularly preferred are the above-described polycarbonate diols based on 1, 6-hexanediol having an average molecular weight of 800-3000 g/mol and/or the product carbonates of the reaction of 1, 6-hexanediol with epsilon-caprolactone in a molar ratio of from 1 to 0.33.

Preference is given to using hydroxy-functional polyamide alcohols as component (D).

Particularly preferred as component (D) are hydroxy-functional polyesters.

Component (F) is a polyisocyanate selected from the group consisting of: aromatic, araliphatic, aliphatic or cycloaliphatic polyisocyanates or mixtures of such polyisocyanates (F). Preferred polyisocyanates are selected from the group consisting of: 1, 3-cyclohexane diisocyanate, 1-methyl-2, 4-diisocyanatocyclohexane, 1-methyl-2, 6-diisocyanatocyclohexane, 1, 4-diisocyanatobutane, 4 '-diisocyanatodiphenylmethane, 2, 4-diisocyanatotoluene, 2, 6-diisocyanatotoluene, alpha', '-tetramethyl-m-xylylene diisocyanate, alpha', tetramethyl-p-xylylene diisocyanate, 1, 6-diisocyanatohexane, 1-isocyanato-3, 3, 5-trimethyl-5-isocyanatomethylcyclohexane (isophorone diisocyanate or IPDI), 4-isocyanatomethyl-1, 8-octanedionate (nonane triisocyanate), 4' -dicyclohexylmethane diisocyanate and mixtures thereof, if appropriate also from other isocyanates and/or higher functional homologues and/or oligomers having urethane, biuret, carbodiimide, isocyanurate, allophanate, iminooxadiazinedione and/or uretdione groups.

The polyisocyanate component (F) preferably contains at least 60% by weight of cycloaliphatic and/or aliphatic isocyanates having a functionality of at least 2.

It is particularly preferred that the polyisocyanate component (F) comprises 1-isocyanato-3, 3, 5-trimethyl-5-isocyanatomethylcyclohexane (isophorone diisocyanate or IPDI), 1-methyl-2, 4/(2, 6) -diisocyanatocyclohexane, 4' -dicyclohexylmethane diisocyanate and/or 1, 6-hexamethylene diisocyanate and/or higher functional homologues and/or oligomers having urethane, biuret, carbodiimide, isocyanurate, allophanate, iminooxadiazinedione and/or uretdione groups.

The proportion of cycloaliphatic polyisocyanates, such as 1-isocyanato-3, 3, 5-trimethyl-5-isocyanatomethylcyclohexane (isophorone diisocyanate or IPDI), 1-methyl-2, 4/(2, 6) -diisocyanatocyclohexane and/or 4, 4' -dicyclohexylmethane diisocyanate, is preferably from 50 to 100% by weight, more preferably from 70 to 100% by weight, based on the total polyisocyanate used in the polyurethane dispersion.

Excluded from use in the preparation of the polyurethanes (I) are the reaction products of hydroxyl-containing epoxy (meth) acrylates, such as diglycidyl ethers, with α, β -ethylenically unsaturated monocarboxylic and/or dicarboxylic acids and their anhydrides, examples of which are acrylic acid, methacrylic acid, fumaric acid, maleic anhydride, crotonic acid, itaconic acid and the like, as described in EP-0942022A. Particularly excluded are reaction products of diglycidyl ethers with acrylic acid and/or methacrylic acid.

Suitable oligomeric (meth) acrylates (II) are compounds of component (A1) having a double bond density of greater than 2.0 mol double bonds per kg solids, preferably greater than 3.0 mol double bonds per kg solids. Particular preference is given to oligomeric (meth) acrylates (II) having a double bond density of more than 5.0 mol double bonds per kg solids.

The oligomeric methacrylic acid esters (II) preferably have an OH number of from 5 to 150 mg KOH/g solids, more preferably from 15 to 100 mg KOH/g solids, and very particularly preferably from 15 to 60 mg KOH/g solids.

Component (II) is preferably selected from the group consisting of: (meth) acrylates of tetraols and hexaols, for example pentaerythritol, ditrimethylolpropane, dipentaerythritol, sorbitol, (meth) acrylates of ethoxylated, propoxylated or alkoxylated pentaerythritol, ditrimethylolpropane, dipentaerythritol, sorbitol, and/or technical-grade mixtures obtained in the (meth) acrylation of the above-mentioned alcohol compounds. The oligomeric (meth) acrylates (II) can also be used in the form of mixtures.

In order to increase the molar mass, monoamines and diamines and/or monofunctional or difunctional amino alcohols are used as component (E). Preferred diamines are those which are more reactive towards isocyanate groups than water, since the chain extension reaction of the polyester urethane (meth) acrylate is optionally carried out in an aqueous medium. Particularly preferred are diamines selected from the group consisting of: ethylenediamine, 1, 6-hexamethylenediamine, isophoronediamine, 1, 3-, 1, 4-phenylenediamine, 4, 4' -diphenylmethanediamine, amino-functional polyethylene oxides, amino-functional polypropylene oxides (trade name Jeffamin)Series D [ Hensman, European of Helianthus belgii, Huntsman Corp]) And hydrazine. Particularly preferred is ethylenediamine.

Preferred monoamines are selected from the group consisting of: butylamine, ethylamine and JeffaminAmines of the M series (Henschel, Europe Henschel, Belgium), amino-functional polyethylene oxides, amino-functional polypropylene oxides and/or amino alcohols.

For the preparation of the dispersions of the invention, all methods known in the art can be used, for example the emulsifying/shearing force method, the acetone method, the prepolymer mixing method, the melt-emulsification method, the ketimine method and the solid/spontaneous dispersion method or their derivations. A compilation of these processes is described in Methoden der Organischen Chemie, Houben-Weyl, 4 th edition, volume E20/part 2, page 1682, Georg Thieme Verlag, Stuttgart, 1987. Preferred are the melt emulsification method and the acetone method. Particular preference is given to the acetone process.

To prepare the reaction product according to step i), components (A), (B), (C) and (D) are charged to a reactor and, if appropriate, diluted with acetone. To accelerate the addition reaction with the isocyanate, an isocyanate addition reaction catalyst selected from triethylamine, 1, 4-diazabicyclo- [2, 2, 2] octane, tin dioctoate or dibutyltin dilaurate is added and the mixture is heated to start the reaction. Typically, this step requires a temperature of 30-60 ℃. Then, one or more polyisocyanates (F) are added dropwise. It is also possible to proceed in the reverse manner, introducing the polyisocyanate (F) as initial charge and then adding the isocyanate-reactive components (A), (B), (C) and (D).

To monitor the reaction, the NCO content was periodically determined at regular intervals by titration, infrared spectroscopy or near infrared spectroscopy.

(A) The molar ratio of isocyanate-reactive groups in (A), (B), (C) and (D) to isocyanate groups in (F) is 1: 0, 8-1: 2,5, preferably 1: 1, 2-1: 1, 5.

After the preparation of the product from components (a), (B), (C), (D) and (F) according to step i) of the process of the invention, the salt-forming reaction of the ion-dispersing centers of compound (B) can be carried out if this reaction has not already been carried out in the starting molecule. If component (B) contains acidic groups, preference is given to using bases selected from the following group: triethylamine, ethyldiisopropylamine, dimethylcyclohexylamine, dimethylethanolamine, ammonia, N-methylmorpholine, LiOH, NaOH and/or KOH. If component (B) contains basic groups, it is preferred to use acids selected from the following group: lactic acid, acetic acid, phosphoric acid, hydrochloric acid and/or sulfuric acid. If only ether group-containing compounds are used as component (B), the neutralization step is omitted.

After step i), the oligo (meth) acrylate (II) or a mixture of oligo (meth) acrylates (II) is added. After dissolution of these compounds, the last reaction step is carried out as soon as possible, in which, in an aqueous medium, the molar mass increases to form the polyester urethane (meth) acrylate dispersion necessary for the coating system of the invention: adding the polyurethane synthesized according to step i) from components (a), (B), (C), (D) and (F) and the one or more oligomeric (meth) acrylates (II) in acetone solution to dispersion water containing the one or more amines (E) with vigorous stirring; alternatively, conversely, the dispersing water/amine mixture is added to the polyurethane-oligo (meth) acrylate-acetone solution with stirring. Furthermore, the dispersions present in the coating system of the present invention are formed. The amount of amine (E) used depends on the unreacted isocyanate groups still present. The reaction of residual free isocyanate groups with the amine (E) can be carried out to an extent of 35% to 150%. When the amount of the amine (E) is insufficient, the residual free isocyanate groups react with water and are slowly consumed. When an excess of amine (E) is used, unreacted isocyanate groups are still present, resulting in an amine functional polyurethane. Preferably from 80% to 110%, more preferably from 90% to 100%, of the residual free isocyanate groups are reacted with the amine (E).

Preferably, the reaction of components (A) to (D) with (F) is slowed down at the end of step i) by cooling the reaction mixture, and then component (II) is added with stirring at a reduced temperature, i.e. preferably 30-40 ℃ (step II).

The coating systems obtainable by the process according to the invention are preferred if the difference between the NCO content at the end of step i) and the NCO content theoretically obtainable is from + 2.0% by weight to-1.0% by weight, preferably from 0% by weight to-0.7% by weight, more preferably from-0.1% by weight to-0.5% by weight. Negative difference here means that the NCO content at the end of step i) is below the theoretical NCO content.

In another way, the molecular mass can be increased by the amine (E) before or after the addition of the oligomeric (meth) acrylate (II), while the system remains in solution in acetone.

If desired, in the presence of an organic solvent, the organic solvent may be removed by distillation. The solids content of the dispersion is from 20 to 60% by weight, more preferably from 30 to 58% by weight.

The dispersing step and the distillation step can also be carried out in parallel, i.e. simultaneously.

If the oligomeric (meth) acrylate (II) is added shortly before the dispersing step, component (II) is co-dispersed with the polyurethane synthesized from components (A), (B), (C), (D) and (F). It is disadvantageous that the hydroxyl-containing oligomeric (meth) acrylates (II) are incorporated into the polyurethane framework, which can be prevented by adding the oligomeric (meth) acrylates shortly before the dispersing step.

After evaporation of the water, the dispersions of the invention give transparent films. Radiation-induced and/or free-radical-induced crosslinking is then carried out, as a result of which the film is cured to form a particularly valuable scratch-resistant and chemically resistant film coating.

Suitable radiation sources for radiation-induced polymerization are electromagnetic radiation which emits energy, if appropriate with the addition of suitable photoinitiators, which is sufficient to bring about free-radical polymerization of the (meth) acrylate double bonds.

The radiation-induced polymerization is preferably carried out by radiation having a wavelength of less than 400 nm, for example ultraviolet radiation, electron radiation, X-ray radiation or gamma radiation. Particularly preferred is ultraviolet radiation, wherein curing is initiated by ultraviolet radiation in the presence of a photoinitiator. With regard to photoinitiators, there are in principle two categories: monomolecular type (type I) and bimolecular type (type II). Suitable type I systems are aromatic ketone compounds selected from the group consisting of: combinations of benzophenones with tertiary amines, alkylbenzophenones, 4, 4 '-bis (dimethylamino) benzophenone (Michler's (Michler) ketone), anthrone and halogenated benzophenones, or mixtures of the stated types. Further suitable are the following exemplified type II initiators: benzoin and its derivatives, benzyl ketal (benzyl ketal), acylphosphine oxide, 2, 4, 6-trimethylbenzoyldiphenylphosphine oxide, bisacylphosphine oxide, phenylglyoxylate, camphorquinone, α -aminoalkylphenones (phenones), α -dialkoxyacetophenone, and α -hydroxyalkylphenone. Preferred photoinitiators are readily incorporated into waterborne coatingsThe photoinitiator of (1). An example of such a product is Irgacure500 (mixture of benzophenone and (1-hydroxycyclohexyl) phenylketone, Ciba, Lampertheim, DE, Bluemhybu, Germany), Irgacure819 DW (Phenylbis (2, 4, 6-trimethylbenzoyl) phosphine oxide (Ciba, Blemsbu, Germany), EscapureKIPEM (oligo [ 2-hydroxy-2-methyl-1- [4- (1-methylethenyl) phenyl)]Acetone (II)]Lamberti, Aldizzate, Italy), Adez, Italy. Mixtures of these compounds may also be used.

For the introduction of the photoinitiator, a polar solvent selected from acetone and isopropanol may be used.

If appropriate, UV curing is preferably carried out at temperatures of from 30 to 70 ℃ since higher temperatures tend to increase the extent of reaction of the (meth) acrylate groups. This allows for better tolerability. However, in the case of uv curing, the possible temperature sensitivity of the substrate parts must be taken into account, and therefore the optimum curing conditions for a particular coating/substrate combination must be determined by a person skilled in the art by simple preliminary tests.

If desired, curing is carried out under an inert atmosphere, i.e. excluding oxygen, to prevent oxygen from inhibiting free radical crosslinking.

When curing by the thermal radical method, an aqueous emulsion of a water-soluble peroxide or a water-insoluble initiator is suitably used. These free-radical initiators can be used in a known manner in combination with accelerators.

The coating systems of the present invention can be applied to a wide variety of substrates by conventional techniques, preferably by spraying, roll coating, flow coating, printing, knife coating, casting, spreading, and dipping.

The coating system of the invention can in principle coat or coat all substrates. Preferred substrates are selected from the group consisting of: mineral substrates, wood materials, furniture, wood block flooring, doors, window frames, metal goods, plastics, paper, cardboard, cork, mineral substrates, textiles or leather. In these cases, they are suitable as undercoats and/or topcoats. In addition, the coating systems of the present invention can also be used in or as adhesives, for example in contact adhesives, heat-activated adhesives or laminating adhesives.

The coating systems of the invention can be used alone or as a binder mixture with other dispersions. These further dispersions may be dispersions which likewise contain unsaturated groups, selected from unsaturated dispersions based on polyesters, polyurethanes, polyepoxide (meth) acrylates, polyethers, polyamides, polysiloxanes, polycarbonates, epoxyacrylates, addition polymers, polyester acrylates, polyurethane polyacrylates and/or polyacrylates which contain polymerizable groups.

Such dispersions may also be present in the coating system of the present invention: based on polyesters, polyurethanes, polyethers, polyamides, polyvinyl esters, polyvinyl ethers, polysiloxanes, polycarbonates, addition polymers and/or polyacrylates, which contain functional groups such as alkoxysilyl groups, hydroxyl groups or isocyanate groups, where appropriate in blocked form. In this way, a dual cure system can be produced that can cure by two different mechanisms.

Also for dual-cure systems, it is possible to add so-called crosslinkers to the coating systems of the invention. Preferably, these suitable crosslinking agents include unblocked and/or blocked polyisocyanates, polyaziridines, polycarbodiimides, and melamine resins. Particularly preferred for aqueous coatings are unblocked and/or blocked hydrophilicized (hydrophyllicized) polyisocyanates. The solid crosslinking agent is preferably added in an amount of 20 wt.% or less, more preferably 10 wt.% or less, based on the solid content of the coating material.

The coating system of the invention may also comprise dispersions based on polyesters, polyurethanes, polyethers, polyamides, polysiloxanes, polyvinyl ethers, polybutadienes, polyisoprenes, chlorinated rubbers, polycarbonates, polyvinyl esters, polyvinyl chlorides, addition polymers, polyacrylates, polyurethane-polyacrylates, polyester acrylates, polyether acrylates, alkyds, polycarbonates, polyepoxides, epoxy (meth) acrylates, which do not contain any functional groups. In this way, the crosslink density can be reduced, thereby affecting, e.g., accelerating, physical drying, or producing elasticity or other adhesion-improving effects.

Coatings comprising the coating system of the invention may also comprise an amino crosslinker resin based on melamine or urea, and/or a polyisocyanate having free or blocked polyisocyanate groups, based on polyisocyanates optionally containing hydrophilizing groups formed from 1, 6-yl diisocyanate, isophorone diisocyanate and/or toluene diisocyanate, having urethane, uretdione, iminooxadiazinedione, isocyanurate, biuret and/or allophanate structures added to the component of the coating system of the invention. The crosslinking agent may also be a carbodiimide or polyaziridine.

The coating system of the present invention may be mixed and/or combined with conventional paint technology binders, adjuvants and additives selected from pigments, dyes or slicers. They are flow control additives and wetting additives, slip additives, pigments (including metal effect pigments), fillers, nanoparticles, light stabilizing particles, anti-yellowing additives, thickeners and additives to reduce surface tension.

The coating systems according to the invention are particularly suitable for wood and plastic applications, with a pigment content of > 10% by weight, based on the overall formulation. If the pigment content is high, this can result in incomplete reaction of the radiation-curable groups in the coating system during the radiation curing process, and the resulting coating has blocking resistance.

The coating systems of the invention are likewise particularly suitable for application on wood and plastics which are in close contact with the outside, as are customary articles in everyday use, for example mobile telephone housings, in which case the important factors are low scratch resistance and resistance to chemicals, such as sun protection creams and the like.

The coating system of the present invention is also particularly suitable for foil applications, in which case the coated foil may be deformed between physical drying and radiation curing.

Examples

Gel permeation chromatography measurements were performed using the following system:

pump and method of operating the same	Hewlett Packard 1100 series II
		Syringe with a needle	Hewlett packard 1100 series II
Column heating furnace	VDS-Optilab Jetstream 2Plus
		Detector	Refractive index Detector, HP 1100 series II

Conditions are as follows:

column	PSS HEMA 40; 50 × 7.8 mm 2.PSS HEMA 1000; 300 × 7.8 mm 3.PSS HEMA 300; 300 × 7.8 mm 4.PSS HEMA 40; 300 × 7.8 mm 5.PSS HEMA 40; 300X 7.8 mm
		Mobile phase	N, N-dimethyl acetamide
Flow rate	0.6 ml/min
		Pressure of	100 bar
Temperature of	30℃
		Injection volume	100 microliter
Concentration of sample	13.4 g/l
		Molecular weight standards	PSS Polymer-Standard-Service GmbH, Meinyz, Germany
MP [ g/mol]	162；374；1620；9130；18100；32500；67500；128000；246000；659000；1000000

In each case, the NCO content was monitored by titration determination in accordance with DIN 53185.

After all nonvolatile constituents have been evaporated off, the solids content is determined gravimetrically in accordance with DIN 53216.

The average particle size was measured by laser correlation spectroscopy (laser correlation spectroscopy).

Pendulum hardness (pendulum hardness) was measured in accordance with DIN 53157.

1) Preparation of the UV-curable aqueous polyurethane Dispersion of the invention for use as a Binder in anti-blocking coatings

339.9 parts of a polyester acrylate Laromer as component (A)PE 44F (OH number 80 mg/KOH/g solids, Basf AG, Ludwigshafen, DE) from Lodvisch, Germany, 30.3 parts dimethylolpropionic acid as component (B), 10.7 parts trimethylolpropane as component (C), 199.7 parts 4, 4' -dicyclohexylmethane diisocyanate as component (F) and 0.6 part dibutyltin dilaurate were dissolved in 185 parts of acetone and reacted with stirring at 60 ℃ to an NCO content of 1.90% by weight (theory: 1.72% by weight). The resulting prepolymer solution was mixed with 143.7 parts of dipentaerythritol pentaacrylate Photomer as component (II)4399 (Cognis AG, Dusseldorf, DE, Germany) and component (II) is added with stirring. Then, 21.0 parts of triethylamine was added to neutralize the reaction solution while stirring. The clear solution is added to 1080 parts of water with stirring. Then, a mixture of 10.2 parts of ethylenediamine as component (E) and 24.0 parts of water was added to the dispersion with stirring. Then, the dispersion was removed by distillation under a low vacuumAcetone in the body. This gives the UV-curable aqueous polyurethane dispersion 1) according to the invention having a solids content of 40.1% by weight, an average particle size of 69 nm and a pH of 8.5. Gel permeation chromatography showed a weight average molecular weight Mw of 7.52 x 10⁵G/mol.

2) Preparation of trifunctional polyester:

244.6 parts of trimethylolpropane, 638.1 parts of tetrahydrophthalic acid and 442.9 parts of neopentyl glycol are heated together at 220 ℃ with stirring. The temperature was maintained until the acid number was less than 3.0 mg KOH/g solid. This gave a polyester having a functionality of 3.0 and a hydroxyl number of 250 mg KOH/g solid.

3) Preparation of the UV-curable aqueous polyurethane Dispersion of the invention for use as a Binder in anti-blocking coatings

339.9 parts of a polyester acrylate Laromer as component (A)PE 44F (OH number 80 mg/KOH/g of solid, Pasteur, Lodviesching, Germany), 40.0 parts of dimethylolpropionic acid as component (B), 42.2 parts of the trifunctional polyester of example 2) as component (C), 199.7 parts of 4, 4' -dicyclohexylmethane diisocyanate as component (F) and 0.6 part of dibutyltin dilaurate were dissolved in 195 parts of acetone and reacted with stirring at 60 ℃ until the NCO content was 1.44% by weight (theory: 1.62 wt%). The prepolymer solution obtained was mixed with 115.0 parts of ethoxylated pentaerythritol tetraacrylate Miramer as component (II)4004 (Rahn AG, Zurich, CH, Zurich, Switzerland) and component (II) is added with stirring. Then, 23.6 parts of triethylamine was added to neutralize the reaction solution while stirring. The clear solution was added to 1085 parts water with stirring. Then, a mixture of 8.0 parts of ethylenediamine as component (E) and 24.0 parts of water was added to the dispersion with stirring. The acetone in the dispersion was then removed by distillation under a slight vacuum. Thus obtaining a solidThe UV-curable aqueous polyurethane dispersion 3) according to the invention having a content of 38.3% by weight, an average particle size of 34 nm and a pH of 8.7. Gel permeation chromatography showed a weight average molecular weight Mw of 6.04 x 10⁵G/mol.

4) Preparation of the UV-curable aqueous polyurethane Dispersion of the invention for use as a Binder in anti-blocking coatings

425.6 parts of polyester acrylate Laromer as component (A)PE 44F (OH number 80 mg/KOH/g solids, Pasv, Lodviesching, Germany), 34.0 parts of dimethylolpropionic acid as component (B), 3.1 parts of diethylenetriamine as component (C), 4.8 parts of neopentyl glycol as component (D), 199.7 parts of 4, 4' -dicyclohexylmethane diisocyanate as component (F) and 0.6 part of dibutyltin dilaurate were dissolved in 210 parts of acetone and reacted with stirring at 60 ℃ to an NCO content of 0.92% by weight (theory: 1.07% by weight). The prepolymer solution obtained was mixed with 118.5 parts of ethoxylated pentaerythritol tetraacrylate Miramer as component (II)4004 (Thoni, Zurich, Switzerland) and component (II) is added with stirring. Then, 23.6 parts of triethylamine was added to neutralize the reaction solution while stirring. The clear solution was added to 1155 parts of water with stirring. Then, a mixture of 5.3 parts of ethylenediamine as component (E) and 24.0 parts of water was added to the dispersion with stirring. The acetone in the dispersion was then removed by distillation under a slight vacuum. This gives the UV-curable aqueous polyurethane dispersion 4) according to the invention having a solids content of 43.8% by weight, an average particle size of 55 nm and a pH of 8.6. Gel permeation chromatography showed a weight average molecular weight Mw of 7.51 x 10⁵G/mol.

5) Preparation of the UV-curable aqueous polyurethane Dispersion of the invention for use as a Binder in anti-blocking coatings

339.9 portions are taken as components(A) Polyester acrylate LaromerPE 44F (OH number 80 mg/KOH/g of solid, Pasv, Lodvisch, Germany), 34.0 parts of dimethylolpropionic acid as component (B), 8.2 parts of trimethylolpropane as component (C), 199.7 parts of 4, 4' -dicyclohexylmethane diisocyanate as component (F) and 0.6 part of dibutyltin dilaurate were dissolved in 180 parts of acetone and reacted with stirring at 60 ℃ to an NCO content of 1.80% by weight (theory: 1.72% by weight). Then, 23.6 parts of triethylamine was added to neutralize the reaction solution while stirring. The clear solution was added to 970 parts water with stirring. Then, a mixture of 8.0 parts of ethylenediamine as component (E) and 24.0 parts of water was added to the dispersion with stirring. The acetone in the dispersion was then removed by distillation under a slight vacuum. This gives the UV-curable aqueous polyurethane dispersion 5) according to the invention having a solids content of 40.2% by weight, an average particle size of 31 nm and a pH of 8.4. Gel permeation chromatography showed a weight average molecular weight Mw of 3.54 x 10⁵G/mol.

6) Preparation of polyester acrylate A1 according to example 1 of EP-B872502)

Under stirring and reflux boiling, 224.9 parts of 1, 6-hexanediol, 96.6 parts of trimethylolpropane, 146.0 parts of adipic acid, 144.3 parts of acrylic acid, 3.1 parts of p-toluenesulfonic acid, 1.7 parts of hydroquinone monomethyl ether, 0.6 part of 2, 6-di-tert-butylcresol and 250 n-heptane were reacted at 96 ℃ for 10 hours, and water was separated. Then, the solvent was removed by distillation. An OH number of 165 mg KOH/g, an acid number of 1.0 mg KOH/g and a dynamic viscosity of 520mPas, measured at 23 ℃ in accordance with DIN 53018.

7) Preparation of adduct f1 according to example 1 of EP-B872502)

55.0 parts of 2-hydroxyethyl acrylate and 0.06 parts of dibutyltin oxide were charged into a reaction vessel equipped with a stirrer, a thermometer, a dropping funnel, a reflux condenser and a controllable heating system. While passing intensively through the reaction mixture, the reaction mixture was heated to 110 ℃ and 45.94 parts of ε -caprolactone were metered in over 1 hour via a dropping funnel. The mixture is heated at 110 ℃ for more than 3 hours while stirring until the viscosity at 23 ℃ is 66-70 seconds (sec) measured according to DIN EN ISO 2431.

8) Preparation of a UV-curable aqueous polyurethane Dispersion according to example 1 of EP-B872502

214.0 parts of 1-isocyanato-3, 3, 5-trimethyl-5-isocyanatomethylcyclohexane are added dropwise to a mixture of 200 parts of polyester acrylate 6), 68.4 parts of adduct 7), 36.0 parts of dimethylolpropionic acid and 23.9 parts of triethylamine at a temperature of 55 to 70 ℃ over a period of 3 hours with stirring. In the subsequent reaction carried out at 75-80 ℃ the NCO content had dropped to a constant value of 2.2% by weight. The prepolymer obtained was then dispersed in 749.4 parts of water at a temperature of 38-42 ℃ with vigorous stirring. Then, a mixture of 9.6 parts of ethylenediamine and 14.3 parts of water was added dropwise to the resulting dispersion at the same temperature over 15 minutes, and mixed. Stirring was then continued until the infrared spectrum was 2270 cm^-1Until no more isocyanate was detected. Thus, a UV-curable aqueous polyurethane dispersion 8) having a solids content of 40% by weight, an average particle size of 99 nm and a pH of 7.6 was obtained according to example 1 of EP-B872502. Gel permeation chromatography showed a weight average molecular weight Mw of 3.45 x 10⁴G/mol.

9) Preparation of an aqueous UV-curable polyurethane Dispersion according to example 5 of EP-B942022 41.3 parts of polyester acrylate AgiSyn based on adipic acid720(OH number 116 mg/KOH/g solids, AGI Co., Taipei, Taiwan), 90.1 parts of Polyepoxyacrylate AgiSyn1010(OH number 240 mg/KOH/g solid, AGI, Taipei, Taiwan), 17.1 parts of dimethylolpropionic acid, 33.6 parts of 1, 6-hexamethylene diisocyanate, 44.4 parts of 1-isocyanato-3, 3, 5-trimethylThe base-5-isocyanatomethylcyclohexane and 0.24 part of dibutyltin dilaurate are dissolved in 131 parts of acetone and reacted with stirring at 60 ℃ until the NCO content is 1.60% by weight (theory: 1.25% by weight). Then, 12.7 parts of triethylamine was added to neutralize the solution while stirring. The clear solution is added to 500 parts of water with stirring. Then, a mixture of 3.6 parts of ethylenediamine and 30.0 parts of water was added to the dispersion with stirring. The acetone in the dispersion was then removed by distillation under a slight vacuum. Thus, a UV-curable aqueous polyurethane dispersion 9) having a solids content of 32.8% by weight, an average particle size of 90 nm and a pH of 8.4 was obtained according to example 5 of EP-B942022. Gel permeation chromatography showed a weight average molecular weight Mw of 9.03 x 10⁴G/mol.

10) Preparation of an aqueous UV-curable polyurethane Dispersion according to example 2 of EP-B753531 150.2 parts of a polyester acrylate Laromer8800(OH number 70 mg/KOH/g solids, Pasv, Lodvisch, Germany), 15.0 parts of dimethylolpropionic acid, 24.0 parts of 1, 6-hexamethylene diisocyanate, 31.7 parts of 1-isocyanato-3, 3, 5-trimethyl-5-isocyanatomethyl-cyclohexane and 0.22 part of dibutyltin dilaurate were dissolved in 129 parts of acetone and reacted with stirring at 60 ℃ until an NCO content of 2.20% by weight (theory: 1.92% by weight). Then, 11.2 parts of triethylamine was added to neutralize the reaction solution while stirring. The clear solution is added to 515 parts of water with stirring. Then, a mixture of 3.6 parts of ethylenediamine and 30.0 parts of water was added to the dispersion with stirring. The acetone in the dispersion was then removed by distillation under a slight vacuum. Thus, a UV-curable aqueous polyurethane dispersion 10) having a solids content of 29.0% by weight, an average particle size of 180 nm and a pH of 7.7 was obtained according to example 2 of EP-B735531. Gel permeation chromatography showed a weight average molecular weight Mw of 8.40 x 10⁴G/mol.

Performance testing

Table 1: preparation

Table 2: application and curing conditions

	Varnish [1 ]]	Varnish [ 2]]	Varnish [3 ]]
				Base material	Glass	Bayfol³	Makrofol⁴
Application by blade coating	Box-type doctor blade (Box-typewriter), 1X 120 micron, wet film	Wire type doctor blade (Wiredoctor), 1X 100 micron, wet film	Wire type doctor blade, 1X 100 micron, wet film
				Degassing time	10 min, room temperature and 30 min, 50 deg.C	10 min, room temperature and 30 min, 50 deg.C	10 min, room temperature and 30 min, 50 deg.C
Curing	Hg⁵	Hg⁵	Hg⁵

Solutions of polyether-modified polydimethylsiloxane from BYK of Wetherl, Germany (BYK, Wesel, DE)

²Mixture of 50% by weight of 1-hydroxycyclohexyl phenyl ketone and 50% by weight of benzophenone from Ciba, Bluembub, Germany

³Technical-grade films consisting of polycarbonate mixtures and ABS from Leverkusen Bayer materials science, Germany

⁴Technical-grade films composed of polycarbonate from Levokusen Bayer materials science, Inc., Germany

⁵UV system from Kraffle (Cefla), I (about 80W/cm, about 1000 mJ/cm)²)

After uv curing, the coated substrates were stored at room temperature for 16 hours and then tested.

Table 3 a: performance test data

Table 3 b: performance test data

⁶The resistance properties were assessed visually after 5 minutes of exposure. "good" means that the film has no optical change from the previous.

⁷The resistance properties were assessed visually after 16 hours of exposure.

100%: no visible damage and no softening of the film

80%: slight visible optical change, no softening of the film

60%: without visible damage, but the film softened

40%: slight visible damage and softening of the film

20%: visible damage is evident and the film softens

0%: the surface is damaged

Inventive examples 1-4 show a non-stick surface having water resistance after drying and prior to uv radiation curing. Comparative examples 8-10 did not have water resistance before UV curing, even with very high pendulum hardness as was the case in example 9.

Although the invention has been described in detail in the foregoing for the purpose of illustration, it is to be understood that such detail is solely for that purpose and that variations can be made therein by those skilled in the art without departing from the spirit and scope of the invention except as it may be limited by the claims.

Claims

1. A coating system based on a radiation curable aqueous polyurethane dispersion comprising:

I) polyurethanes obtained from A), B), C), D), E) and F):

A)40-80 wt% of a hydroxyl-containing component comprising:

B)0.1 to 20% by weight of one or more compounds reactive toward isocyanate groups, which contain groups of the nonionic, ionic or ionic group-forming type and have a dispersing action on polyurethane dispersions,

C)0.1-30 wt.% of a hydroxyl and/or amine containing component comprising:

and/or

D) 0 to 30% by weight, based on the total weight of components (a) to (F) and (II), of a hydroxy-functional compound selected from the group consisting of: mono-and/or di-alcohols, all having a molecular weight in the range of 32 to 118 g/mol; polyesters, polycarbonates, C2, C3 and/or C4 polyethers, polyether esters and polycarbonate polyesters, all having a functionality of from 1.0 to 2.0 and molecular weights in the range of 300-4000 g/mol,

with the proviso that no polyepoxide (meth) acrylate is used in the synthesis of (I),

and

2. The radiation-curable aqueous polyurethane dispersion-based coating system according to claim 1, wherein component (C1) comprises aliphatic or cycloaliphatic triols, tetraols, hexaols, triamines and/or tetraamines having from 3 to 10 carbon atoms.

3. The radiation-curable aqueous polyurethane dispersion-based coating system according to claim 1, wherein component (C1) comprises glycerol, trimethylolethane, trimethylolpropane, trimethylolbutane, pentaerythritol, ditrimethylolpropane, dipentaerythritol, sorbitol, glucose, fructose, diethylenetriamine and/or triethylenetetramine.

4. The radiation-curable aqueous polyurethane dispersion-based coating system according to claim 1, wherein component (C2) comprises a polyesterol selected from the group consisting of: adipic acid, isophthalic acid and phthalic anhydride with trimethylolpropane, glycerol, pentaerythritol, hexanediol, butanediol, diethylene glycol, monoethylene glycol or neopentyl glycol or mixtures of the abovementioned diols.

5. The radiation-curable aqueous polyurethane dispersion-based coating system according to claim 4, wherein the polyesterol has a molecular weight of 300-4000 g/mol.

6. The radiation-curable aqueous polyurethane dispersion-based coating system according to claim 1, wherein component (C2) comprises polyethylene glycol, polypropylene glycol and/or polytetrahydrofuran.

7. The radiation-curable aqueous polyurethane dispersion-based coating system according to claim 1, wherein the weight-average molecular weight MW of the mixture of (I) and (II) present in the coating system is 100000-2000000 g/mol.

8. A radiation-curable aqueous polyurethane dispersion-based coating system according to claim 1, wherein the coating system comprises at least initiators and, if desired, auxiliaries and additives, which allow curing under high-energy radiation.

9. A method of preparing the coating system of claim 1, comprising the steps of:

II) mixing component II with the reaction product of step i), and

10. The process of claim 9 wherein the reaction of residual free isocyanate groups of the polyurethane prepolymer with component (E) is carried out to an extent of from 80% to 110%.

11. The process according to claim 9, wherein the difference between the NCO content at the end of step i) and the theoretically obtainable NCO content is between + 2.0% and-1.0% by weight.

12. An adhesive or paint comprising the coating system of claim 1.

13. A substrate coated with the paint of claim 12.

14. The substrate of claim 13, wherein the substrate is selected from the group consisting of: mineral substrates, wood materials, furniture, wood flooring, doors, window frames, metal goods, plastics, paper, cardboard, cork, mineral substrates, textiles, and leather.

15. A dual cure system comprising the coating system of claim 1.