TW201333061A - Process for the preparation of low-viscosity, water-dilutable urethane (meth) acrylates - Google Patents

Abstract

The present invention relates to a process for the preparation of highly reactive, low-viscosity and water-dilutable polyisocyanate reaction products which contain activated groups which react, by polymerization, with ethylenically unsaturated compounds under the action of actinic radiation. The present invention furthermore relates to a process for the preparation of such products and their use.

Description

Method for preparing low viscosity and water-dilutable (meth)acrylic polyurethane

The present invention is directed to a process for preparing a highly reactive, low viscosity, water-dilutable polyisocyanate reaction product comprising an activating group which is reacted with an ethylenically unsaturated compound by polymerization under actinic radiation. The invention also relates to products prepared by the process and to their use.

Coating systems with activated double bonds are known to cure by actinic radiation and are based on the industry. Actinic radiation is understood to mean electromagnetic, ionizing radiation, in particular electron beams, UV rays and visible light (Roche Lexikon Medizin, 4th edition; Urban & Fischer Verlag, Munik 1999). It is one of the fastest curing methods in coating technology. Coating compositions based on this principle are therefore referred to as radiation- or actinic-curing or -curable systems.

On the one hand, it is desirable to use paint materials that are already low-viscosity, and on the other hand, because of the lacquer ecology and economics requirements for adjusting the viscosity of the current lacquer system with as little organic solvent as possible or even without using organic solvents. The necessary viscosity adjustment can be carried out using water as a solvent.

Polyurethane dispersions whose viscosity is controlled by water are widely used and have themselves been identified as radiation-curing materials in the paint industry. Nonetheless, such dispersions are more difficult to prepare due to the necessary dispersion steps and typically have only a low solids content of 30 to 50 wt%. The high water content of these dispersions must be removed again after application and prior to curing. On the one hand, the applicable thickness of the material is thus reduced, and on the other hand, it needs to be dried in air for a longer period of time.

A water-dilutable radiation curable polyurethane system which can be used to obtain an extremely high solids content of more than 80% by weight has also been disclosed. These are generally based on polyoxyethylene polyols Polyurethane and can be diluted with a small amount of water to obtain a clear solution.

Such radiation curable, water-dilutable polyurethane systems are described, for example, in WO-A 2009/095432. The disclosed adhesives can indeed be diluted with water, but after radiation curing, they are very soft and resistant to chemicals. The storage stability of the solution diluted with water needs to be improved. In addition, the UV reactivity of these adhesives also needs to be improved.

Water-compatible radiation curable polyurethane systems are also described in DE-A 102010001956. The disclosed adhesives can also be diluted with water, but after radiation curing, they are very soft and chemically resistant. The storage stability of the solution diluted with water also needs to be improved. These products also have UV reactivity that is worth improving.

Accordingly, it is an object of the present invention to provide a process for preparing a radiation curable (meth)acrylic acid polyurethane having an undiluted system having a solid content of 100 wt%. Particularly low viscosity, ie shear viscosity at 23 ° C 100,000 mPas, especially preferred 50,000 and special preference 30,000, and can be diluted with water within a wide range. In addition, UV reactivity should be improved. In addition, water-dilutable radiation-curable (meth)acrylic urethanes should be storage stable. Radiation-cured films should have improved pendulum hardness and adequate chemical resistance. The viscosity was measured using a cone-plate rotational viscometer, MCR 51 (available from Anton Paar, DE), according to ISO/DIS 3219:1990, at a shear rate of 50 s ^-1 .

Specific embodiments of the invention

An embodiment of the invention is a process for preparing a low viscosity, water-dilutable (meth)acrylic acid polyurethane comprising reacting components (a), (c), (d) and (e) Forming the low viscosity, water-dilutable (meth)acrylic polyurethane: (a) at least one oligomeric polyisocyanate having an average of at least three isocyanate groups; (c) at least one poly a polyoxyalkylene mono-ol; (d) at least one hydroxyalkyl (meth) acrylate; (e) at least one polyoxyalkylene polyol based on a starting molecule having at least three a hydroxyl functional group and partially reacted by esterification with (meth)acrylic acid, so that it remains flat Each has from 0.2 to 1.5 hydroxyl functional groups; wherein the low viscosity, water-dilutable (meth)acrylic polyurethane has an NCO content of less than 0.5 wt%.

Another embodiment of the present invention is the above process, wherein the other component (b) is reacted with components (a), (c), (d) and (e), and at least one of the components (b) has at least one Additional isocyanate of two isocyanate functional groups.

Another embodiment of the present invention is the above process, wherein the other component (f) is reacted with components (a), (c), (d) and (e), the component (f) having at least one having at least A compound reactive toward isocyanates and at least one ionic and/or potentially ionic functional group.

Another embodiment of the present invention is the above process, wherein (a) is at least one oligomeric polyisocyanate based on 1,6-hexamethylene-diisocyanate.

Another embodiment of the present invention is the above process, wherein (a) is at least one oligomeric polyisocyanate having a trimeric isocyanate group.

Another embodiment of the present invention is the above process, wherein the polyoxyalkylene monool (c) comprises at least 30 mol% of ethylene oxide units.

Another embodiment of the present invention is the above process, wherein component (c) is a polyoxyethylene monol having an OH number of from 18 to 238 mg KOH/g.

Another embodiment of the present invention is the above process, wherein component (e) comprises an average of from 0.5 to 8.0 ethylene oxide units per OH group of the starting molecule.

Another embodiment of the present invention is the above process, wherein the process uses 20 to 50 wt% of component (a), 0 to 20 wt% of component (b), and 10 to 30 wt% of component (c) 4 to 20 wt% of component (d), 25 to 60 wt% of component (e) and 0 to 10 wt% of component (f), wherein components (a) to (f) are wt The sum of % is 100.

Another embodiment of the present invention is a water-dilutable (meth)acrylic polyurethane obtained by the above process.

Another embodiment of the present invention is a coating comprising the above water-dilutable (meth)acrylic polyurethane.

Another embodiment of the invention is the above coating, wherein the coating is a lacquer or a binder.

Another embodiment of the present invention is a coating composition comprising the above water-dilutable (meth)acrylic polyurethane.

Another embodiment of the invention is a coating composition comprising A) at least one of the above-mentioned urethane (meth) acrylates; B) a compound which is different from A) and which is included in a group that reacts with an ethylenically unsaturated compound by actinic radiation; C) a non-radiation-curable aqueous binder; D) an initiator; E) an optional water and/or solvent; F) an optional aid Materials and / or additives.

Another embodiment of the invention is a substrate coated with the coating composition.

Another embodiment of the present invention is the above substrate, wherein the substrate is wood, wood substrate, cork, or a substrate comprising cellulose fibers.

Detailed description of the invention

Surprisingly, it has been found that a low viscosity, water-dilutable (meth)acrylic polyurethane is prepared, characterized in that the low viscosity, water-dilutable (meth)acrylic acid can be obtained by reacting the following components. Polyurethane (a) at least one oligomeric polyisocyanate having an average of at least three isocyanate groups, (b) optionally at least one additional isocyanate having at least two isocyanate functional groups (c) at least one polyoxyalkylene a monolol, (d) at least one hydroxyalkyl (meth) acrylate, (e) at least one polyoxyalkylene polyol based on a starting molecule having at least three hydroxyl functional groups and The esterification of the acrylic acid is partially reacted such that an average of 0.2 to 1.5, preferably 0.3 to 1.3 and particularly preferably 0.5 to 1.5 hydroxyl functional groups are retained, (f) optionally at least one having at least one isocyanate-reactive The group and the compound of at least one ionic and/or latent ionic functional group are characterized in that the reaction product has an NCO content of less than 0.5%.

In the context of the present invention, the term "water-dilutable" means that the polyurethane of the invention is miscible with water. This means that the viscosity of the polyurethane of the present invention does not exceed the viscosity of the polyurethane of the present invention having a solid content of 100 wt% when diluted with water. A solids content of 100 wt% means that the polyurethane system is not diluted with water.

The invention also provides water-dilutable (meth)acrylic polyurethanes obtainable by the process according to the invention.

The invention also provides (meth)acrylic polyurethanes according to the invention obtainable by the process according to the invention for the preparation of coatings and lacquers as well as adhesives, printing inks, moulding resins, dental compositions, compounds ( The use of sizes, photoresists, stereolithography systems, resins for composite materials, and sealing compositions.

In the context of the present invention, "(meth)acrylate" relates to the corresponding acrylate or methacrylate functional group or a mixture of the two.

Oligo-polyisocyanate (a) having an average of at least three NCO groups having a polyisocyanate, a biuret, an allophanate and/or an imine A polyisocyanate of a diketone group. Suitable oligomeric polyisocyanates are for example based on the following: 1,3-cyclohexane-diisocyanate, 1-methyl-2,4-diisocyanato-cyclohexane, 1-methyl-2, 6-diisocyanato-cyclohexane, tetramethylene-diisocyanate, 4,4'-diisocyanatodiphenylmethane, 2,4'-diisocyanatodiphenylmethane, 2,4-diisocyanatotoluene, 2,6-diisocyanatotoluene, α,α,α',α'-tetramethyl-m- or p-benzodimethyl-diisocyanate, 1 ,6-hexamethylene-diisocyanate, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (1-isocyanato-3,3 ,5-trimethyl-5-isocyanatomethylcyclohexane or IPDI), 4,4'-diisocyanatodicyclohexylmethane, 1,3-bis(isocyanatomethyl) Benzene (XDI), 1,3-bis(1-isocyanato-1-methylethyl)benzene (TMXDI) and mixtures thereof. Preference is given to oligomeric polyisocyanates based on 1,6-hexamethylene-diisocyanate (HDI), particular preference being given to trimeric isocyanate groups based on 1,6-hexamethylene-diisocyanate (HDI) Oligomeric polyisocyanate.

Possible isocyanate-containing compounds (b) are aromatic, aliphatic and alicyclic polyisocyanates. Suitable polyisocyanates are compounds of the formula Q(NCO)n having an average molecular weight of less than 800, wherein n represents a value from 2 to 4, and Q represents an aromatic C6-C15-hydrocarbyl group, an aliphatic C4-C12-hydrocarbyl group or a lipid. a cyclo C6-C15-hydrocarbyl group, for example a diisocyanate from the following series: 2,4-/2,6-toluene-diisocyanate (TDI), methylene diphenyl-diisocyanate (MDI), triisocyanate Hexane (TIN), Naphthyl-diisocyanate (NDI), 4,4'-diisocyanatodicyclohexylmethane, 3-isocyanatomethyl-3,3,5-trimethylcyclohexyl-isocyanate (isophor) Keto-diisocyanate=IPDI), tetramethylene-diisocyanate, 1,6-hexamethylene-diisocyanate (HDI), 2-methylpentamethylene-diisocyanate, 2,2,4-three Methylhexamethylene-diisocyanate (THDI), dodecamethylene-diisocyanate, 1,4-diisocyanatocyclohexane, 4,4'-diisocyanato-3,3' -Dimethyldicyclohexylmethane, 4,4'-diisocyanatodicyclohexyl-2,2-propane, 3-isocyanatomethyl-1-methyl-1-isocyanato Cyclohexane (MCI), 1,3-diisooctyl cyanoxy-4-methylcyclohexane, 1,3-diisocyanato-2-methylcyclohexane and α,α,α ',α'-Tetramethyl-m- or p-xylylene-diisocyanate (TMXDI) and mixtures comprising these compounds.

The above isocyanate itself or a reaction product of each other produces, for example, a uretdione, a trimeric isocyanate, an allophanate, a biuret, an imine Diketone and/or oxadione Polyisocyanates of the triketone structure are described, for example, by way of example in J. Prakt. Chem. 336 (1994) 185-200 and EP-A 0 798 290, which are likewise suitable as compounds (b) which comprise isocyanates.

According to the invention, the polyoxyalkylene monool (c) is used as a compound having a nonionic hydrophilic effect. These polyoxyalkylene monools contain from 30 wt% to 100 wt% of units derived from ethylene oxide. Preference is given to using polyoxyalkylenes which comprise, by means of alkoxylation of suitable starting molecules, for example, in a manner known per se, comprising from 5 to 70, preferably from 7 to 55, ethylene oxide units per molecule in statistical mean. Alcohols (for example Ullmanns Encyclopädie der technischen Chemie, 4th edition, Vol. 19, Verlag Chemie, Weinheim 31-38).

Such compounds have an OH number of from 18 to 238 mg KOH/g, preferably from 56 to 187 mg KOH/g and very particularly preferably from 70 to 160 mg KOH/g.

The OH number was determined by titration according to DIN 53240-2.

Suitable starting molecules for the preparation of these polyoxyalkylene monools are, for example, saturated monohydric alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, secondary butanol, isomeric pentanol, Hexanol, octanol and decyl alcohol, n-decyl alcohol, dodecanol, n-tetradecyl alcohol, n-hexadecanol, n-octadecyl alcohol, cyclohexanol, isomeric methylcyclohexanol or hydroxymethylcyclohexane, 3-ethyl-3-hydroxymethyloxetane or tetrahydrofurfuryl alcohol, diethylene glycol monoalkyl ether, such as diethylene glycol monobutyl ether, unsaturated alcohol, such as allyl alcohol, 1,1 - dimethylallyl alcohol or oleyl alcohol, an aromatic alcohol such as phenol, isomeric cresol or methoxyphenol, an aryl aliphatic alcohol such as benzyl alcohol, anisole or cinnamyl alcohol, a secondary monoamine such as dimethylamine , diethylamine, dipropylamine, diisopropylamine, dibutylamine, bis-(2-ethylhexyl)-amine, N-methyl- and N-ethylcyclo Hexylamine or dicyclohexylamine, and a heterocyclic secondary amine such as morpholine, pyrrolidine, piperidine or 1H-pyrazole. Preferred starting molecules are saturated monohydric alcohols, and a particularly preferred starting molecule is methanol or ethanol.

Suitable alkylene oxides for alkoxylation are, for example, ethylene oxide, 1-butene oxide and propylene oxide, preferably ethylene oxide and propylene oxide, which may be in the alkoxylation reaction in any desired order or in the form of a composition. use.

The polyoxyalkylene monol is a pure polyoxyethylene polyfluorene monol or a mixed polyoxyalkylene polyether monol whose oxyalkylene unit comprises at least 30 mol%, preferably at least 50 mol% of ethylene oxide units. Particular preference is given to using pure polyoxyethylene monools.

The hydroxyalkyl (meth) acrylate (d) in the context of the present invention is understood to mean a compound which comprises one or more (meth) acrylate groups in addition to (average) one hydroxy function. The various functional groups in this case are bonded by a short chain (C2-C12) linear or branched alkyl chain. Examples of such compounds are hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, 3-hydroxy-2,2-dimethylpropane (meth)acrylate Ester, glyceryl di(meth)acrylate, trimethylolpropane di(meth)acrylate, neopentyl alcohol tri(meth)acrylate or dineopentaerythritol penta(meth)acrylate.

Preference is given to using hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate. Very particular preference is given to hydroxyethyl acrylate and hydroxypropyl acrylate.

The use of at least one polyoxyalkylene polyol based on a starting molecule having at least three hydroxyl functional groups is essential to the invention. On the one hand, this component produces a higher water compatibility and on the other hand it contributes to the high reactivity of the products of the invention. Component e) comprises partially esterified short chain alkoxylated polyols which have been formed from an average of from 0.5 to 8.0, preferably from 3.0 to 6.0, alkylene oxide per hydroxyl group, preferably oxyethylene units.

Possible starting molecules are low molecular weight polyols having a molecular weight of up to 400 g/mol, such as trimethylolethane, trimethylolpropane, glycerol, pentaerythritol, ditrimethylolpropane or dipentane Tetraol.

The polyoxyalkylene polyol is partially esterified with (meth)acrylic acid, preferably with acrylic acid. In this connection, the degree of esterification is selected such that an average of 0.2 to 1.5, preferably 0.3 to 1.3, particularly preferably 0.5 to 1.2, of the hydroxyl group remains, and the remaining hydroxyl groups are esterified with (meth)acrylic acid. The preparation of such partially acrylated alkoxylated, preferably ethoxylated, polyols is described, for example, in EP-A 0900778, EP-A 0976716 or WO-A 2003/022902.

The compound classified as component (e) preferably has an OH content of from 20 mg KOH/g to 200 mg KOH/g, particularly preferably from 40 mg KOH/g to 150 mg KOH/g, very particularly preferably from 50 to 100 mg KOH/g. number.

Component (f) comprises a compound having at least one isocyanate-reactive group and at least one additional ion and/or potential ionic group. It has a hydrophilic effect on the (meth)acrylic acid urethane of the present invention.

The group having a hydrophilic action includes an ionic group (f1) and/or an ionic group (f1) derived from a latent ionic group (f2) (for example by salt formation), which may be anionic (f1.1), such as sulfur Ruthenium, phosphonium, carboxylate, sulfonate, phosphonate groups, or cationic (f1.2), such as ammonium, and/or potentially ionic (f2), ie, can be converted to ions, for example by salt formation a group of the group (f1). They are introduced into the polymer by isocyanate-reactive groups. Preferred suitable isocyanate-reactive groups are hydroxyl and amine groups.

Compounds containing a potential ionic group (f2) include compounds having a latent anionic group (f2.1), such as mono- and di-hydroxycarboxylic acids, mono- and diaminocarboxylic acids, mono- and di-hydroxysulfonic acids, mono- and diamines Sulfonic acid, mono and dihydroxyphosphonic acid, mono and diaminophosphonic acids and/or compounds having a latent cationic group (f2.2), such as ethanolamine, diethanolamine, triethanolamine, 2-propanolamine, Propanolamine, tripropanolamine, N-methylethanolamine, N-methyldiethanolamine and N,N-dimethylethanolamine.

Preferred compounds comprising a potential anionic group (f2.1) are selected from the group consisting of dimethylolpropionic acid, dimethylolbutanoic acid, hydroxypivalic acid, N-(2-aminoethyl)-alanine, 2 -(2-Aminoethylamino)-ethanesulfonic acid, ethylenediamine-propyl- or butylsulfonic acid, 1,2- or 1,3-propanediamine-ethylsulfonic acid, 3-( Cyclohexylamino)propane-1-sulfonic acid, malic acid, citric acid, glycolic acid, lactic acid, glycine, alanine, taurine, lysine, 3,5-diaminobenzoic acid, acrylic acid and The ratio of the amine (for example, isophorone diamine (EP-A 916 647, Example 1) or ethylenediamine (PUD salt or N-(2-aminoethyl)-β-alanine)) is 1 An addition product of :1, an adduct of sodium hydrogen sulfite with but-2-ene-1,4-diol polyether sulfonate and a propoxylated adduct of 2-butenediol and NaHSO3, See Equations I-III on pages 5-9 of DE-A 2446 440.

Particularly preferred compounds containing a latent ionic group (f2) are compounds comprising a carboxyl group, a sulfonic acid group and/or a tertiary amino group, such as 2-(2-aminoethylamino)-ethanesulfonic acid, 3-( Cyclohexylamino)propane-1-sulfonic acid in a ratio of 1:1 acrylic acid on diamines, such as isophorone diamine (EP-A 916 474 Example 1) or Ethylene Amine (PUD salt or N-(2-aminoethyl)-β-alanine Addition product of acid), hydroxypivalic acid, dimethylolpropionic acid, triethanolamine, tripropanolamine, N-methyldiethanolamine and/or N,N-dimethylethanolamine.

Component (f) very particularly preferably comprises acrylic acid and a diamine in a ratio of 1:1, such as isophoronediamine (EP-A 916 474 Example 1) or ethylenediamine (PUD salt or N-(2) An addition product of -aminoethyl)-β-alanine as a compound having a latent ionic group.

The acid under the component (f) mentioned is converted to the corresponding salt by reaction with a neutralizing agent such as triethylamine, ethyldiisopropylamine, dimethylcyclohexylamine, Methylethanolamine, ammonia, N-ethylmorpholine, LiOH, NaOH and/or KOH. In this case, the degree of neutralization is preferably from 50 to 125%. The degree of neutralization is defined as follows: in the case of an acid-functionalized polymer, the quotient of the base and the acid; in the case of a base-functionalized polymer, the quotient of the acid and the base. If the degree of neutralization is higher than 100%, in the case of an acid-functionalized polymer, more base is added than the acid group present in the polymer; in the case of an alkali-functionalized polymer, addition ratio polymerization is added. More base acid is present in the base.

The base under the component (f) mentioned is converted to the corresponding salt by reaction with a neutralizing agent such as a mineral acid such as hydrochloric acid, phosphoric acid and/or sulfuric acid, and/or an organic acid such as formic acid. , acetic acid, lactic acid, methane-, ethane- and/or p-toluenesulfonic acid. In this case, the degree of neutralization is preferably from 50 to 125%.

The compounds of component (f) listed may also be used in the form of a mixture.

However, it is preferred not to use component (f).

The component (a) is used in an amount of 20 to 50% by weight, preferably 25 to 40% by weight, particularly preferably 26 to 35% by weight, and the component (b) is used in an amount of 0 to 20% by weight, preferably 0 to 10%. The wt%, particularly preferably 0 wt%, the component (c) is used in an amount of 10 to 30 wt%, preferably 12 to 25 wt%, particularly preferably 13 to 20 wt%, and the component (d) is used in an amount of 4 To 20 wt%, preferably 5 to 15 wt%, very particularly preferably 6 to 12 wt%, component (e) is used in an amount of 25 to 60 wt%, preferably 30 to 55 wt%, particularly preferably 40 to 52 wt%, and component (f) are used in an amount of from 0 to 10% by weight, preferably from 0 to 5% by weight, very particularly preferably 0% by weight, provided that the weight % of the components (a) to (f) is Is 100.

The reaction of the isocyanate-containing component (a) and optionally (b) with the isocyanate-reactive component (c), (d), (e), optionally (f) is known per se to those skilled in the art. It is carried out in a urethanation reaction.

In this case, the isocyanate-containing compound (a) and optionally (b) and the isocyanate-reactive component (c), (d), (e), and optionally (f) are from 1:0.9 to 1:1.5. , preferably 1:1 to 1:1.2 and particularly preferably 1:1 Equivalent ratio reaction to 1:1.05.

The neutralization of optional component (f) can be carried out before, during or after the reaction with component (a) and optionally (b).

The reaction is carried out at 25 to 100 ° C, preferably 40 to 80 ° C, for 2 to 30 hours, preferably 4 to 15 hours.

In this case, the reaction is carried out until the residual NCO content reaches less than 0.5%, preferably less than 0.3%.

In order to accelerate the reaction, it is preferred to use a catalyst. For this purpose, polyuretization catalysts known per se to the person skilled in the art, such as tertiary amines or Lewis acids, are possible. There are organotin compounds which may be mentioned by way of example, such as dibutyltin diacetate, dibutyltin dilaurate, dibutyltin diacetate, or zinc compounds such as zinc acetylacetonate or zinc octoate. It is also conceivable to use a Lewis acid metal compound containing molybdenum, vanadium, zirconium, hafnium, tantalum or tungsten.

In the process according to the invention, if used together, the catalyst component is used in an amount of from 0.001 to 5.0% by weight, based on the solids content of the product of the process, preferably from 0.001 to 0.1% by weight solids.

Solvents and/or reactive diluents may optionally be employed at any desired point in the process according to the invention. Preferably no solvent and/or reactive diluent is used.

Suitable solvents are inert to the functional groups present in the product of the process from the point in time of addition to the end of the process. For example, solvents used in the lacquer technique are suitable, such as hydrocarbons, ketones and esters such as toluene, xylene, isooctane, acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, butyl acetate, tetrahydrofuran, N-methylpyrrolidone, dimethylacetamide, dimethylformamide, but preferably no solvent is added.

Compounds which are likewise (co)polymerized during radiation curing and thus introduced into the polymer network and which are inert to the NCO groups can be used together as a reactive diluent. Such reactive diluents are described by way of example in P. K. T. Oldring (ed.), Chemistry & Technology of UV & EB Formulations For Coatings, Inks & Paints, Vol. 2, 1991, SITA Technology, London, pp. 237-285. These may be esters of acrylic or methacrylic acid, preferably acrylic acid, with mono- or polyfunctional alcohols. Suitable alcohols are, for example, isobutanol, pentanol, hexanol, heptanol, octanol, decyl alcohol and decyl alcohol, and furthermore, for example alicyclic alcohols, such as isobornyl alcohol, cyclohexanol and alkylated cyclohexanol, Dicyclopentanol, aryl aliphatic alcohols such as phenoxyethanol and nonylphenylethanol, and tetrahydrofurfuryl alcohol. Furthermore, alkoxylated derivatives of these alcohols can be used. A suitable difunctional alcohol is The following alcohols, such as ethylene glycol, 1,2-propylene glycol, 1,3-propanediol, diethylene glycol, dipropylene glycol, isobutylene glycol, neopentyl glycol, 1,6-hexanediol, 2 Ethylhexanediol and tripropylene glycol, or alkoxylated derivatives of these alcohols. Preferred difunctional alcohols are 1,6-hexanediol, dipropylene glycol and tripropylene glycol. Suitable trifunctional alcohols are glycerol or trimethylolpropane or alkoxylated derivatives thereof. The tetrafunctional alcohol is neopentyl alcohol or an alkoxylated derivative thereof. A suitable hexafunctional alcohol is dipivaloerythritol or an alkoxylated derivative thereof. Alkoxylated derivatives of the tri- to hexafunctional alcohols mentioned are particularly preferred.

The binder according to the invention is preferably stabilized by relatively premature polymerization. Therefore, a polymerization preventing stabilizer is added as a component of one or more components ((a) to (f)) before and/or during the reaction. Examples of suitable stabilizers are, for example, phenothiazines And phenol, such as p-methoxyphenol, 2,5-ditributylhydroquinone or 2,6-ditributyl-4-methylphenol. N-oxyl compounds are also suitable for stabilization, such as 2,2,6,6-tetramethylpiperidine N-oxide (TEMPO) or derivatives thereof. Stabilizers may also be introduced together into the binder in the same chemical, in which case compounds of the abovementioned classes are suitable, especially if they also carry other free aliphatic alcohol groups or primary or secondary amine groups. And can therefore be chemically bonded to the compound of component a) by means of a polyurethane or urea group. 2,2,6,6-tetramethyl-4-hydroxypiperidine N-oxide is particularly suitable for use herein.

Other stabilizers such as compounds of the HALS (HALS = Hindered Amine Light Stabilizer) class can likewise be used, but are not preferred.

An oxygen-containing gas, preferably air, may be passed through or through the reaction mixture to stabilize the reaction mixture, particularly to inhibit prematurely polymerized unsaturated groups. The gas preferably has the lowest possible moisture content to prevent undesired reactions in the presence of isocyanate.

The stabilizer may be added during the preparation of the binder according to the invention, and in order to obtain long-term stability, it may be finally post-stabilized with a phenol stabilizer, and the reaction product may optionally be air saturated.

In the process according to the invention, the preferred stabilizer component is used in an amount of from 0.001 to 5.0% by weight, preferably from 0.01 to 2.0% by weight and particularly preferably from 0.05 to 1.0% by weight, based on the solids content of the process product.

The process according to the invention is preferably carried out in a stirred reactor.

The reaction process can be monitored by appropriate measuring instruments installed in the reactor and/or by means of analysis of the obtained samples. Suitable methods are known to those skilled in the art. They are for example Viscosity measurement, NCO content measurement, refractive index measurement, OH content measurement, gas chromatography (GC), nuclear magnetic resonance spectroscopy (NMR), infrared spectroscopy (IR) and near infrared spectroscopy (NIR). Monitoring the infrared spectrum of the free NCO groups present (for aliphatic NCO groups, the band in the infrared spectrum is approximately υ = 2272 cm-1) and GC analysis of unreacted compounds from a) and optionally b) It is preferred.

The unsaturated (meth)acrylic polyurethane obtainable by the process of the invention preferably has a solids content of 100 wt% at 23 ° C 100,000 mPas, especially preferred 50,000 mPas and special preference Shear viscosity of 30,000 mPas. The viscosity was measured using a cone-plate rotational viscometer, MCR 51 (available from Anton Paar, DE, according to ISO/DIS 3219: 1990) at a shear rate of 50 s-1.

The (meth)acrylic polyurethane prepared by the process of the invention can be diluted with water as required to produce the desired viscosity.

The radiation-curable (meth)acrylic polyurethane of the invention can be used for preparing coatings and lacquers as well as adhesives, printing inks, mold resins, dental compositions, sizing agents, photoresists, stereolithography System, resin and sealing composition for composite materials. However, in the case of gluing or sealing, it is premised that at least one of the two substrates to be glued or sealed to each other during radiation curing must be permeable to the radiation used for curing, ie generally transparent. . If an electron beam is used for curing, it is necessary to ensure sufficient permeability to electrons. The use of (meth)acrylic urethane as a binder in paints and coatings is preferred.

The invention further provides a coating composition comprising A) one or more (meth)acrylic polyurethanes according to the invention, B) optionally other compounds which are different from A) and which are included in the light a group which reacts with an ethylenically unsaturated compound by polymerization, C) optionally, other non-radiation curable aqueous binder, D) an initiator, E) optionally, a solvent and/or water, F) optionally, auxiliary materials and additives.

The compounds of component B) include non-aqueous compounds, such as, in particular, (meth)acrylic acid polyurethanes, which are preferably based on hexamethylene-diisocyanate, 1-isoisocyanato-3,3, 5-trimethyl-5-isoisocyanate methylcyclohexane, 4,4'-diisoisocyanate dicyclohexylmethane and/or trimethylhexamethylene-diisocyanate, which can Any choice of trimeric isocyanate, allophanate, biuret, uretdione and / or imido oxadi The triketone group is modified and has no groups reactive toward isocyanate groups.

In addition, if the reactive diluent does not contain a group reactive with the NCO group, the already described reactive diluent known in the art as a radiation-curable coating can also be used as a component of B).

The compounds of component B) also include compounds which are dissolved or dispersed in water, such as in particular dispersions comprising unsaturated radiation curable groups, for example comprising unsaturated radiation curable groups and based on polyesters, polyaminocarboxylic acids Esters, polyepoxy (meth) acrylates, polyethers, polyamines, polyoxyalkylenes, polycarbonates, polyepoxy acrylates, polyester acrylates, polyurethane acrylates and/or Or a dispersion of polyacrylate. In this case, the unsaturated radiation curable group may be present in combination with one of the polymers and/or in the form of a radiation curable monomer (so-called reactive diluent) The polymers are present together in the dispersion.

The compounds of component C) also comprise compounds which are dissolved or dispersed in water, such as, in particular, dispersions which do not comprise unsaturated radiation curable groups, for example based on polyesters, polyurethanes, polyethers, polyfluorenes. A dispersion of an amine, polyoxyalkylene, polycarbonate, polyurethane polyacrylate and/or polyacrylate.

In particular, if components B) and C) are compounds which are dissolved or dispersed in water, for example in particular dispersions, the addition of the water-dilutable (meth)acrylic acid polyurethanes according to the invention is Advantageously, the solids content of components B) and C) can be increased in such a way that the resulting viscosity is not greatly increased.

Initiators which can be activated by radiation and/or heat can be used as initiators for component D) for free-radical polymerization. Photoinitiators activated by UV or visible light are preferred herein. There are differences in principle between the two photoinitiators, single molecule (type I) and bimolecular (type II). Suitable (type I) systems are aromatic ketone compounds such as benzophenone, alkyl benzophenone, 4,4'-bis(dimethylamino)benzophenone (in combination with tertiary amines) Michler ketone), anthrone and halogenated benzophenone or a mixture of the mentioned types. (Type II) initiators, such as benzoin and its derivatives, benzil ketal, decylphosphine oxides, such as 2,4,6-trimethyl-benzimidyl-diphenyl Phosphine oxide, bisphosphonium phosphide oxide, phenylglyoxylic acid esters, hydrazine, α-aminoalkyl phenyl ketone, α,α-dialkoxyethyl benzene and α- A-hydroxyalkylphenones are also suitable.

The amount is from 0.1 to 10% by weight, preferably from 0.1 to 5% by weight, based on the weight of the lacquer binder The initiators can be used as separate substances or can also be used in combination with one another due to the common advantageous synergistic effects.

If an electron beam is used instead of UV radiation, no photoinitiator is required. As is known to those skilled in the art, electron radiation is generated by means of thermal emission and accelerated by a potential difference. The high energy electrons then penetrate the titanium film and deflect toward the coating composition to be cured. The main principles of electron beam curing are described in "Chemistry & Technology of UV & EB Formulations for Coatings, Inks & Paints", Vol. 1, PKT Oldring (ed.), SITA Technology, London, UK, pages 101-157, 1991. A detailed description.

In the case of thermal curing of the activated double bond, this can also be carried out by adding a free-radical thermal dissociating agent. Suitable reagents are, for example, peroxy compounds such as dialkoxydicarbonates, such as bis(4-tert-butylcyclohexyl)peroxydicarbonate, dialkyl peroxygen, as known to those skilled in the art. For example, dilauryl peroxide, a perester of an aromatic or aliphatic acid, such as tertiary butyl perbenzoate or tertiary amyl peroxy-2-ethylhexanoate, an inorganic peroxide, for example Ammonium hydrogen peroxide, potassium hydrogen peroxysulfate, organic peroxides such as 2,2-bis(tertiary butylperoxy)butane, dicumyl peroxide, tertiary butyl hydroperoxide, or Azo compounds such as 2,2'-azobis[N-(2-propenyl)-2-methylpropionamide], 1-[(cyano-1-methylethyl)azo] Indoleamine, 2,2'-azobis(N-butyl-2-methylpropionamide), 2,2'-azobis(N-cyclohexyl-2-methylpropionamide), 2 , 2'-Azobis{2-methyl-N-[2-(1-hydroxybutyl)]propanamine},2,2'-azobis{2-methyl-N-[2- (1-Hydroxybutyl)]propanamide, 2,2'-azobis{2-methyl-N-[1,1-bis(hydroxymethyl)-2-hydroxyethyl]propanamide. Highly substituted 1,2-diphenylethane (benzopinacol) such as 3,4-dimethyl-3,4-diphenylhexane, 1,1,2,2-tetraphenylethane -1,2-diol or its formazan alkylated derivative is also possible.

Combinations of photoinitiators and thermally activatable initiators can also be used.

Organic solvents which are known per se to the person skilled in the art can also optionally be used together as component E). However, it is preferred to use water as the sole diluent.

The composition may also contain UV absorbers and/or HALS stabilizers as auxiliary materials and additives (component F)) to increase the stability of the cured paint layer to weathering. Combinations of UV absorbers and HALS stabilizers are preferred. The former advantageously has an absorption range not higher than 390 nm, such as triphenyl III Type (eg Tinuvin® 400 (Ciba Spezialitätenchemie GmbH, Lampertheim, DE)), benzotriazole (eg Tinuvin® 622 (Ciba Spezialitätenchemie GmbH, Lampertheim, DE)) or grass diphenylamine (eg Sanduvor® 3206 (Clariant, Muttenz) , UV)) The UV absorber is added in an amount of from 0.5 to 3.5% by weight based on the solid resin. Suitable HALS stabilizers are commercially available (Tinuvin® 292 or Tinuvin® 123 (Ciba Spezialitätenchemie GmbH, Lampertheim, DE) or Sanduvor® 3258 (Clariant, Muttenz, CH)). A preferred amount is from 0.5 to 2.5% by weight based on the solid resin.

Likewise, F) may also contain other auxiliary materials and additives known in the lacquer technique, such as pigments, including metallic effect pigments, dyes, matting agents, fillers, flow agents, wetting agents and degassing additives, slips (slip) Additives, nanoparticles, anti-yellowing additives, thickeners and additives for reducing surface tension.

The coating composition according to the invention is applied to the material to be coated using conventional and known methods in coating techniques, such as spraying, knife coating, roll coating, pouring, dipping, spin coating, brushing or fine misting. Coating, or by printing techniques such as screen printing, gravure printing, flexographic or offset printing, and transfer methods.

Suitable substrates are, for example, wood, metal, in particular metals used in the application of so-called wires, coils, cans or containers, and plastics, as well as plastics in the form of films, in particular ABS, AMMA, ASA, CA, CAB, EP, UF, CF, MF, MPF, PF, PAN, PA, PE, HDPE, LDPE, LLDPE, UHMWPE, PET, PMMA, PP, PS, SB, PU, PVC, RF, SAN, PBT, PPE, POM, PU-RIM, SMC, BMC, PP-EPDM and UP (according to DIN 7728 part 1), paper, leather, fabric, mat, glass, wood, wood, cork, Artificial adhesive substrates, such as wood and fiber cement boards, electronic components or mineral substrates. Substrates comprising various of the above materials, or already coated substrates, such as vehicles, aircraft or ships and their components, particularly body or accessories, may also be painted. It is also possible to apply the coating composition only temporarily to the substrate, then partially or completely cure them, and optionally separate them again, for example to produce a film.

In particular, the coating composition according to the invention is suitable for coating wood, wood-containing substrates, cork and substrates comprising cellulose fibers, such as paper or cardboard.

For curing, if present, for example, water or solvent may be completely or partially removed by evaporation in air.

Thermal and/or photochemical curing can be carried out during or after evaporation in air.

If necessary, the thermal curing can be carried out at room temperature, but it can also be carried out at an elevated temperature, preferably 40 to 160 ° C, preferably 60 to 130 ° C, particularly preferably 80 to 110 ° C.

If a photoinitiator is used in D), the radiation curing is preferably, for example, by means of UV radiation or sunlight, for example radiation of light having a wavelength of 200 to 700 nm, or by means of radiation of high-energy electrons (electron radiation, 150 to 300 keV). , under the action of actinic radiation. For example, a high or medium pressure mercury vapor lamp can be used as a source of radiation for light or UV radiation, which can be modified by doping with other elements such as gallium or iron. Laser, pulse light (known as UV flash), halogen or excimer light is also available. The lamp can be designed by its design or using a special screening program and/or mirror to prevent the emission of a portion of the UV spectrum. For example, for industrial hygiene reasons, for example, radiation assigned to UV-C or UV-C and UV-B can be filtered out. The lamp can be mounted in a fixed position such that the item to be irradiated passes through the source of radiation by means of mechanical means, or the lamp can be moved, the item to be irradiated does not change its position during curing. The radiation dose which is usually sufficient to crosslink in UV curing is from 80 to 5,000 mJ/cm2.

The radiation can also optionally be carried out in the presence of oxygen, for example under an inert atmosphere or under an atmosphere of reduced oxygen. Suitable inert gases are preferably nitrogen, carbon dioxide, noble gases or combustion gases. Radiation can also be carried out by covering the coating with a medium that is transparent to radiation. Examples of these are, for example, plastic films, glass, or films of liquids such as water.

The type and concentration of the initiator that is optionally used varies in a manner known to those skilled in the art, depending on the radiation dose and curing conditions.

It is particularly preferred to use a high pressure mercury vapor lamp mounted in a fixed position for curing. The photoinitiator is then used in a concentration of from 0.1 to 10% by weight, particularly preferably from 0.2 to 3.0% by weight, based on the solids of the coating. To cure these coatings, it is preferred to use a dose of 200 to 3,000 mJ/cm2 as measured in the wavelength range of 200 to 600 nm.

If a heat-activatable initiator is used in D), the curing is carried out by raising the temperature. In this case, thermal energy can be introduced into the coating by radiation, heat conduction and/or convection, infrared lamps, near-infrared lamps and/or ovens commonly used in coating technology.

Curing is preferably carried out by actinic radiation.

The applied layer thickness (before curing) is usually from 0.5 to 5,000 μm, preferably from 5 to 1,000 μm, particularly preferably from 15 to 200 μm. If a solvent is used, it is removed by a usual method after application and before curing.

The present invention also provides a method of preparing a coating on wood, a wood substrate, a softwood, and a substrate comprising cellulose fibers, characterized in that the coating composition according to the present invention is applied as described above Wood, wood substrates, cork and substrates comprising cellulosic fibers are then cured as described above.

The invention also provides a substrate coated with a coating composition according to the invention, the coating composition comprising a (meth)acrylic polyurethane prepared by the process according to the invention.

All of the above references are incorporated by reference in their entirety for all utility purposes.

While the invention has been shown and described with respect to the specific embodiments of the present invention, it will be apparent to those skilled in the art that various modifications and rearrangements can be made in various parts without departing from the spirit and scope of the basic inventive concept. And the same is not limited to the specific manner shown and described herein.

Example

All percentage data are by weight unless otherwise stated.

The solids content of the polyurethane dispersion is determined gravimetrically after all the non-volatile components have been evaporated according to DIN EN ISO 3251.

The NCO content, in %, is determined by reverse titration with 0.1 mol/l hydrochloric acid after reaction with butylamine according to DIN EN ISO 11909.

According to ISO/DIS 3219:1990, a plate-plate rotary viscometer from Haake, DE, at a shear rate of 47.94/s, at 23 ° C for a (meth)acrylic polyamine The acid ester is measured for viscosity.

The ambient temperature of 23 ° C at which the experiment was carried out was called RT.

The OH number was determined according to DIN 53240-2.

The acid number is determined according to DIN EN ISO 2114.

Desmodur ^® N 3600: aliphatic polyisocyanate (low viscosity HDI terpolymer), solvent free, NCO content 23.0%, viscosity: 1,200 mPa. s/23°C (Bayer MaterialScience AG, Leverkusen, DE)

MPEG 500: a methanol-initiated polyoxyethylene monol having a number average molecular weight (Mn) of 500 g/mol

Desmodur ^® T80: 2,4- and 2,6-toluene-diisocyanate (TDI) at a ratio of 80:20, Bayer MaterialScience AG, Leverkusen, DE

Carbowax® PEG 3000: Polyoxyethylene diol with a number average molecular weight (Mn) of 3,000 g/mol, Dow, Midland, Michigan, US

Carbowax® PEG 4000: Polyoxyethylene diol with a number average molecular weight (Mn) of 4,000 g/mol, Dow, Midland, Michigan, US

Polyol R 4290: alkoxylated polyol (15 times ethoxylated pentaerythritol), Perstorp Holding AB, Perstorp, SE

Polyol R 4630: 5 times ethoxylated pentaerythritol, Perstorp Holding AB, Perstorp, SE

Epilox® A-1900: Bisphenol A diglycidyl ether, Leuna-Harze GmbH, Leuna, DE

Partially acrylated alkoxylated polyol 1

910.5 g of OH number of 455.2 g of isooctane is 255 mg KOH / g of trimethylolpropane starting oxyethylene polyether (4 oxyethylene units / trimethylolpropane per OH) Group), 198.2 g of acrylic acid, 11.5 g of p-toluenesulfonic acid, 9.2 g of p-methoxyphenol and 0.6 g of 2,5-di-tert-butylhydroquinone were initially introduced into a 4,000 ml four-neck glass flask. The glass flask was equipped with a reflux condenser, a heated oil bath, a mechanical stirrer, an air-passing line (4 l/h), an internal thermometer, a dropping funnel and a water separator, and was heated to 95 °C. After about 36 hours under reflux, 50.5 g of water was separated, at which point the acid value was 3.4 mg KOH/g. The isooctane was distilled off at 50 ° C under reduced pressure. Then, 19.6 g of glycidyl methacrylate was added at 90 ° C, and the mixture was stirred at 100 ° C for an additional 1 hour. A colorless resin was obtained with an acid value of 0.4 mg KOH/g, an OH functionality (per molecule) of 1.11, an alkylene oxide content of 66 wt%, and a viscosity of 189 mPas (23 ° C).

Example 1: Water-dilutable binder of the present invention

350.12 g of Desmodur® N3600, 1.20 g of 2,6-ditributylbutyl-4-methylphenol and 0.72 g of dibutyltin dilaurate were initially introduced into a 2,000 ml four-necked glass flask with The reflux condenser was heated to an oil bath, a mechanical stirrer, an air-passing line (2 l/h), an internal thermometer and a dropping funnel, and heated to 60 °C. Then, 88.66 g of hydroxyethyl acrylate, 570.47 g of partially acrylated alkoxylated polyol 1 and finally 188.74 g of MPEG 500 were continuously added dropwise so that the temperature did not exceed 65 °C. The mixture is then stirred until the theoretical NCO value has dropped below 0.2%. A clear, slightly pale yellow resin was obtained with a residual NCO content of 0.0% and a viscosity of 19,040 mPas (23 ° C).

Example 2 (Comparative): Example 3 similar to DE-A 102010001956

363.03 g of polyethylene glycol 1000, 0.56 g of dimethylolpropionic acid, 3.79 g of neopentyl glycol, 67.36 g of hydroxyethyl acrylate, 191.68 g of dipropylene glycol diacrylate, 0.56 g of 2, 6-di-tributyl-4-methylphenol, 0.06 g phenothiazine 0.56 g of tempol, 0.03 g of 2,5-di-tert-butylhydroquinone and 0.40 g of dibutyltin dilaurate were initially introduced into a 2,000 ml four-necked glass flask with a reflux condenser, which was heated Oil bath, mechanical stirrer, air line (2 l/h), internal thermometer and dropping funnel, and heated to 60 °C. Then 139.00 g of Desmodur® T80 was added dropwise so that the temperature did not exceed 70 °C. The mixture was then stirred until the NCO value reached 0.26%. Then 21.46 g of dibutylamine was added and the mixture was stirred at 65 ° C for an additional two hours. Finally, an additional 117.46 g of dipropylene glycol diacrylate was mixed. A colorless resin was obtained with a viscosity of 8,000 mPas (23 ° C).

Example 3 (Comparative): Example 1 similar to WO-A 2009/095432

210.6 g of Carbowax® PEG 3000, 187.2 g of Carbowax® PEG 4000 was initially introduced into a 2,000 ml four-necked glass flask with 58.50 g of isophorone diisocyanate (see above) and 316 g of acetone. The reflux condenser was heated to an oil bath, a mechanical stirrer, an air-passing line (2 l/h), an internal thermometer and a dropping funnel, and heated to 50 °C. Then, 0.8 g of dibutyltin dilaurate was added, and the mixture was stirred at 60 ° C for about two hours. Subsequently, 0.8 g of 2,6-di-tertiary butyl-4-methylphenol was first added, then 336 g of pentaerythritol triacrylate was added, and the mixture was stirred at 70 ° C until the NCO value had reached less than 0.2%. . After distilling off acetone under reduced pressure, a resin which was solid at 23 ° C was obtained.

Example 4 (Comparative): Example 2 similar to WO-A 2009/095432

674 g of Polyol R 4290, 935 g of Polyol R 4630, 653 g of isooctane, 16.8 g of p-toluenesulfonic acid, 6.7 g of 4-methoxyphenol, 0.45 g of 2,5-II Butylhydroquinone and 751 g of acrylic acid were initially introduced into a 2,000 ml four-necked glass flask with a reflux condenser, heated oil bath, mechanical stirrer, air-passing line (2 l/h), internal thermometer With a water separator, the temperature slowly rises to the boiling point of isooctane (95-105 ° C) until a strong reflux has developed. Then about 125 g of water was separated, and when the acid value reached 4 mg KOH/g, the reaction was stopped. The water separator was replaced with a distillation bridge, first isooctane was distilled off under normal pressure, and then isooctane was distilled off under reduced pressure of 50 mbar. Then 76 g of Epilonx® A-1900 was mixed and the mixture was stirred at 100 ° C for about 1 hour.

808 g of the product obtained in this way was initially introduced into a 1,000 ml four-necked glass flask together with 0.44 g of 2,6-ditributyl-4-methylphenol and 0.74 g of dibutyltin dilaurate. The glass flask was equipped with a reflux condenser, a heated oil bath, a mechanical stirrer, an air-passing line (1 l/h), an internal thermometer and a dropping funnel, and heated to 60 °C. Then 40.8 g of Desmodur® I was slowly added dropwise, followed by stirring the mixture at 60 ° C until the NCO content had fallen below 0.2%. A colorless resin was obtained with a viscosity of 830 mPas.

Paint preparation and use test

The prepared water-dilutable (meth)acrylic acid polyurethane and 3% by weight of Irgacure® 500 (mixture of benzophenone and 1-hydroxycyclohexyl phenyl ketone from BASF SE, Ludwigshafen, DE) And the corresponding amount of water (see Tables 4 and 5), mixed under shear force in a dispersion device at 2,000 revolutions for 10 minutes. The mixture was stretched as a film onto a glass or oak sheet by means of a box scraper having a gap of 90 μm. After UV radiation (medium pressure mercury lamp, IST Metz GmbH, Nürtingen, DE, 411 mJ/cm2), a clear solid coating was obtained.

The reactivity of each zone was set and the reactivity was measured during the product (90 μm) (see above) which was drawn onto the glass by ultraviolet irradiation (medium pressure mercury lamp, IST Metz GmbH, Nürtingen, DE). Determine the highest tape run rate for the film that still gets the tack. Therefore, a higher value indicates a higher reactivity.

The stability of the paint was tested at 23 ° C (RT) depending on how many days after phase separation or sedimentation occurred. Sex.

The adhesion to the oak was tested according to the DIN EN ISO 2409 by means of the cross-hatch adhesion test. (Level 0: The trimming is completely flat; there is no squares of the grid splitting.).

The hardness of the König pendulum on the test glass is tested according to DIN EN ISO 1522.

Chemical resistance tests were carried out on oak chips according to DIN 68861-1 and DIN EN 12720, for example 10% strength sodium hydroxide solution or 48% strength ethanol. (Level 5: Paint remains unchanged, Grade 1: Significant changes in the surface, such as paint detachment).

After dilution with at least 20 wt% water, all products immediately showed very good adhesion to wood.

Example 1 of the present invention has an acceptable hardness of more than 50 pendulum seconds and is stable at higher water dilutions. However, contrary to Example 3 (comparative), Example 1 of the present invention also has a low viscosity at a solid content of 100 wt% (i.e., undiluted), and is non-solid, and has a significantly lower concentration in various dilutions. Viscosity. Example 1 additionally has better chemical (ethanol) resistance. Finally, it can be clearly seen that the examples of the invention have significantly higher reactivity than the comparative examples.

Claims (16)

A method of preparing a low viscosity, water-dilutable (meth)acrylic acid polyurethane, the method comprising reacting components (a), (c), (d) and (e) to form the low viscosity And a water-dilutable (meth)acrylic acid polyurethane: (a) at least one oligomeric polyisocyanate having an average of at least three isocyanate groups; (c) at least one polyoxyalkylene monool; (d) at least a hydroxyalkyl (meth) acrylate; (e) at least one polyoxyalkylene polyol based on a starting molecule having at least three hydroxyl functional groups and partially esterified by (meth)acrylic acid The reaction is such that an average of 0.2 to 1.5 hydroxyl functional groups are still retained; wherein the low viscosity and water-dilutable (meth)acrylic polyurethane has an NCO content of less than 0.5 wt%. The method of claim 1, wherein the other component (b) is reacted with components (a), (c), (d) and (e), and at least one of the components (b) has at least one Additional isocyanate of two isocyanate functional groups. The method of claim 1, wherein the other component (f) is reacted with the components (a), (c), (d) and (e), the component (f) having at least one of at least one A compound reactive toward isocyanate and a compound of at least one ionic and/or potentially ionic functional group. The method of claim 1, wherein (a) is at least one oligomeric polyisocyanate based on 1,6-hexamethylene-diisocyanate. The method of claim 1, wherein (a) is at least one oligomeric polyisocyanate having a trimeric isocyanate group. The method of claim 1, wherein the polyoxyalkylene monool (c) comprises at least 30 mol% Oxidized ethylene unit. The method of claim 1, wherein component (c) is a polyoxyethylene monol having an OH number of 18 to 238 mg KOH/g. The method of claim 1, wherein component (e) comprises an average of from 0.5 to 8.0 ethylene oxide units per OH group of the starting molecule. The method of claim 1, wherein the method uses 20 to 50 wt% of component (a), 0 to 20 wt% of component (b), and 10 to 30 wt% of component (c), 4 to 20 wt% of component (d), 25 to 60 wt% of component (e) and 0 to 10 wt% of component (f), wherein wt% of components (a) to (f) The sum is 100. A water-dilutable (meth)acrylic acid urethane obtained by the method of claim 1 of the patent application. A coating comprising a water-dilutable (meth)acrylic polyurethane as in claim 10 of the patent application. The coating of claim 11, wherein the coating is a lacquer or a binder. A coating composition comprising a water-dilutable (meth)acrylic polyurethane as described in claim 10 of the patent application. A coating composition comprising A) at least one (meth)acrylic acid polyurethane as in claim 10; B) optionally a compound different from A), and the compound is contained in the light a group that reacts with an ethylenically unsaturated compound via polymerization; C) optionally, a non-radiation curable aqueous binder; D) an initiator; E) optionally, water and/or a solvent; F) optionally, an auxiliary material and/or an additive. A substrate coated with a coating composition of claim 13 of the patent application. The substrate of claim 14, wherein the substrate is wood, wood substrate, cork, or a substrate comprising cellulosic fibers.