Radiation curable aqueous polyurethane dispersions with excellent application technology performance

Abstract

The present invention relates to radiation curable polyurethane dispersions with particularly high double bond density. The polyurethane dispersions can be used alone as coating compositions, or in particular advantageously as additives in conventional polyacrylate dispersions or radiation-curable polyurethane dispersions in order to improve their technical performance of application.

Description

[0001] This invention relates to radiation-curable polyurethane dispersions having a particularly high double bond density. These polyurethane dispersions can be used alone in coating compositions, or particularly advantageously as additives in conventional polyacrylate dispersions or radiation-curable polyurethane dispersions to improve their application performance.

[0002] Polyacrylate dispersions are commonly used in coating compositions due to their very low production cost. However, their performance in application is often less than satisfactory. Two-component polyurethane dispersions are a better alternative when high-quality coatings are required. However, these polyurethane dispersions have a limited pot life due to the reactivity of the isocyanate used as a crosslinking agent and typically require specialized equipment. Furthermore, they are more expensive than polyacrylate dispersions.

[0003] The research upon which this invention is based indicates that the hydrophilicity (e.g., as measured by acid value) and double bond density of the dispersion are particularly crucial, thus enabling good miscibility with polyacrylate dispersions and improving their technical application properties. This is especially beneficial for anti-blocking and chemical resistance. It should be emphasized that the dispersions of this invention contain no co-solvents other than reactive diluents.

[0004] EP 1 869 097 describes, in a very general sense, compositions containing olefinically unsaturated oligomers and resins that do not contain energy-curing functional groups. Oligomers having the properties described in this invention are not described herein.

[0005] EP 0 453 838 describes urethane oligomers with a high density of olefinic unsaturated groups. However, these oligomers have low acid values ​​and contain co-solvents.

[0006] JP 2008-303258 describes nonionic hydrophilic urethane acrylates. Due to their nonionic hydrophilicity, they have no acid value and differ from the reaction products of this invention.

[0007] US 2016 / 0304742 describes a polyurethane polymer obtained by chain extension of an isocyanate-terminated prepolymer. Due to the proportions of the structural components, the oligomers contained in the dispersion of this invention no longer contain free isocyanate groups without chain extension. This invention is defined by the claims and the embodiments described in the following specification.

[0008] In a first embodiment, the present invention relates to an aqueous composition comprising a product obtained or available from a reaction mixture, the reaction mixture comprising... a) Polyisocyanate component A, with an average isocyanate functionality of at least 2.2 NCO groups per molecule; b) At least one ionic or potentially ionic hydrophilic compound B, each molecule of which contains at least one isocyanate reactive group; c) Radiation-curable component C, each molecule of which contains at least 2 (meth)acrylate groups; The composition has a double bond density of at least 7 mol / kg, based on its total weight.

[0009] The term "reaction mixture" refers to a mixture containing components A, B, and C, and optionally at least one catalyst, in a form that enables the crosslinking of hydroxyl and isocyanate groups to form urethane groups.

[0010] In a preferred embodiment, the reaction mixture comprises components A, B, and C to a degree of at least 90%, more preferably at least 95%, more preferably at least 98% (based on the total weight of all compounds present therein excluding water and inert solvents).

[0011] The reaction products of components A, B and optional C preferably have an acid value of at least 80 mg KOH / g.

[0012] The molar ratio of hydroxyl groups to isocyanate groups in the reaction mixture is preferably 1:1 to 1.2:1 at the start of the reaction.

[0013] The term "inert solvent" refers to an organic compound used as a solvent in the reaction mixture but which itself cannot react with isocyanate groups or hydroxyl groups. They also do not contain radiation-curable groups, especially olefinically unsaturated groups. Adding such inert solvents during synthesis may be suitable; they are separated by distillation during the preparation of the aqueous compositions of the present invention. Preferred inert solvents include N-methylpyrrolidone, N-ethylpyrrolidone, butyl acetate, ethyl acetate, methoxypropyl acetate, diethylene glycol dimethyl ether, dioxane, dimethylformamide, xylene, toluene, naphtha, cyclohexanone, methyl isobutyl ketone, diethyl ketone, methyl ethyl ketone, and acetone.

[0014] The polyisocyanate component A present in the reaction mixture reacts with an ionic or potentially ionic hydrophilic compound B to form a product, which is also referred to below as "the reaction product of the present invention". The acid value of the product is preferably determined according to DIN EN ISO 2114: 2002-06.

[0015] If component C contains hydroxyl-functionalized molecules, the aqueous composition of the present invention contains the following reaction products: (i) molecules formed solely by components A and B, and (ii) molecules formed by components A, B, and C. Because hydroxyl-functionalized component C also contains molecules without free hydroxyl groups due to its low OH value, free molecules of component C are always present. In this case, the "product" having the acid value of the present invention is a mixture of reaction products (i) and (ii).

[0016] Based on its total weight, the aqueous composition of the present invention preferably contains less than 5% by weight, more preferably less than 1% by weight, of an inert solvent.

[0017] Polyisocyanate component A The term "polyisocyanate composition A" refers to the sum of all compounds in the reaction mixture that have at least one isocyanate group per molecule. The key to this invention is that all components of the polyisocyanate component have an average of at least 2.2 isocyanate groups per molecule; that is, the presence of molecules with an isocyanate functionality less than 2.2 must be compensated for by the presence of a sufficient amount of molecules with an isocyanate functionality greater than 2.2.

[0018] Polyisocyanate component A preferably comprises a polyisocyanate. As used herein, the term "polyisocyanate" is a general term for compounds containing two or more isocyanate groups (as understood by those skilled in the art, this refers to free isocyanate groups having the general formula -N=C=O). The simplest and most important representatives of these polyisocyanates are diisocyanates. Their general formula is O=C=NRN=C=O, where R typically represents an aliphatic, alicyclic, aryliphatic, and / or aromatic group.

[0019] The term "polyisocyanate" as used in this application also refers to monomeric and / or oligomeric polyisocyanates. However, in order to understand many aspects of the invention, it is essential to distinguish between monomeric diisocyanates and oligomeric polyisocyanates. When "oligomeric polyisocyanate" is mentioned in this application, it refers to a polyisocyanate formed from at least two monomeric diisocyanate molecules, i.e., a compound constituting or comprising the reaction product of at least two monomeric diisocyanate molecules.

[0020] In this article, the preparation of oligomeric polyisocyanates from monomeric diisocyanates is also referred to as the modification of monomeric diisocyanates. The term "modification" here refers to the reaction of monomeric diisocyanates with other optional isocyanate reactive molecules to generate oligomeric polyisocyanates with structures of urea diketone, isocyanurate, urethane, biuret, iminooxadiazine diketone, and / or oxadiazine triketone.

[0021] For example, hexamethylene-1,6-diisocyanate (HDI) is a "monomer diisocyanate" because it contains two isocyanate groups and is not a reaction product of at least two polyisocyanate molecules: In contrast, the reaction products of at least two HDI molecules that still contain at least two isocyanate groups are the "oligomeric polyisocyanates" of this invention. For example, representatives of such "oligomeric polyisocyanates" starting from the monomer HDI are HDI isocyanurate and HDI biuret, which are each formed from three monomer HDI molecules: The weight percentage of isocyanate groups is preferably at least 5% by weight, more preferably at least 10% by weight, based on the total amount of polyisocyanate component A.

[0022] In principle, monomers and oligomeric polyisocyanates are equally applicable to the reaction mixtures of this invention. Therefore, polyisocyanate component A can consist of monomeric polyisocyanates or primarily oligomeric polyisocyanates. It can also contain monomers and oligomeric polyisocyanates in any mixing ratio, provided that their NCO content meets the definition in the subsequent sections of this application.

[0023] However, in a preferred embodiment of the invention, polyisocyanate component A comprises at least one oligomeric polyisocyanate. The monomeric diisocyanate content of polyisocyanate component A is preferably up to 60% by weight, more preferably up to 50% by weight, even more preferably up to 40% by weight, and particularly preferably up to 5.0% by weight, based on the weight of polyisocyanate component A.

[0024] By performing at least one additional process step in each case after the actual modification reaction to separate the unconverted excess monomeric diisocyanate, monomer-poor or essentially monomer-isocyanate-free polyisocyanate compositions can be obtained. This separation of the monomer can be carried out in a particularly practical manner by methods known per se, preferably by thin-film distillation under high vacuum or extraction with a suitable solvent inert to the isocyanate groups (e.g., aliphatic or alicyclic hydrocarbons such as pentane, hexane, heptane, cyclopentane, or cyclohexane).

[0025] In a preferred embodiment of the present invention, a monomer-poor oligomeric polyisocyanate is obtained by modifying the monomeric diisocyanate and then separating the unconverted monomer.

[0026] In another specific embodiment of the method of the present invention, polyisocyanate component A comprises a monomeric isocyanate with an isocyanate functionality greater than 2, i.e., containing more than two isocyanate groups per molecule. Adding a monomeric isocyanate with an isocyanate functionality greater than 2 can be used to adjust the average isocyanate functionality of polyisocyanate component A. Examples of monomeric isocyanates with an isocyanate functionality > 2 include triisocyanate nonane and PMDI.

[0027] According to the present invention, the oligomeric polyisocyanate particularly includes urea diketone, isocyanurate, urethane, biuret, iminooxadiazine diketone, and / or oxadiazine triketone structures. In one embodiment of the present invention, the oligomeric polyisocyanate has at least one of the following oligomeric structural types or a mixture thereof: In a preferred embodiment of the invention, a polyisocyanate component A is used, wherein the isocyanurate structure proportion is at least 50 mol%, preferably at least 60 mol%, more preferably at least 70 mol%, more preferably at least 80 mol%, more preferably at least 90 mol%, and particularly preferably at least 95 mol%, based on the sum of oligomeric structures selected from urea diketone, isocyanurate, urethane, biuret, iminooxadiazine diketone, and oxadiazine triketone structures present in polyisocyanate component A.

[0028] In another preferred embodiment of the invention, in the method of the invention, a polyisocyanate component A is used, which includes not only an isocyanurate structure but also at least one other oligomeric polyisocyanate and mixtures thereof having a structure of urea diketone, biuret, urethane, iminooxadiazine diketone, and oxadiazine triketone.

[0029] For example, the proportions of urea dione, isocyanurate, urethane, biuret, iminooxadiazine dione, and / or oxadiazine trione structures in polyisocyanate component A can be determined by NMR spectroscopy. 13C-NMR spectroscopy is preferred, especially in a proton-decoupled configuration, as the aforementioned oligomeric structures will produce characteristic signals.

[0030] When the isocyanate group content of polyisocyanate component A used according to the present invention is 8.0% to 40.0% by weight, preferably 14.0% to 37.0% by weight, more preferably 20.0% to 35.0% by weight (based on the weight of polyisocyanate component A), results that are particularly consistent with reality are obtained.

[0031] Methods for preparing oligomeric polyisocyanates having structures of urea diketone, isocyanurate, urethane, biuret, iminooxadiazine diketone, and / or oxadiazine triketone, which can be used for polyisocyanate component A, are described in J. Prakt. Chem. 336 (1994) 185–200, DE-A 1 670 666, DE-A 1 954 093, DE-A 2 414 413, DE-A 2 452 532, DE-A 2 641 380, DE-A 3 700 209, DE-A 3 900 053, and DE-A 3 928 503, or EP-A 0 336 205, EP-A 0 339 396, and EP-A 0 798 299.

[0032] In another or alternative embodiment of the invention, polyisocyanate component A is defined as containing oligomeric polyisocyanates obtained from monomeric diisocyanates, wherein regardless of the nature of the modification reaction employed and following a degree of oligomerization of 5% to 45%, preferably 10% to 40%, more preferably 15% to 30%. Here, "degree of oligomerization" is understood to refer to the percentage of isocyanate groups originally present in the starting mixture that are consumed during the preparation process to form urethane, urea diketone, isocyanurate, urethane, biuret, iminooxadiazine diketone, and / or oxadiazine triketone structures.

[0033] Suitable polyisocyanates used to prepare polyisocyanate component A of this invention, as well as the monomers and / or oligomeric polyisocyanates contained therein, are any polyisocyanates obtainable by various methods, such as liquid-phase or gas-phase phosgenation, or by non-phosgene methods, such as thermal urethane pyrolysis. Particularly good results are obtained when the polyisocyanate is a monomeric diisocyanate. Preferred monomeric diisocyanates have a molecular weight of 140 to 400. g / mol of isocyanate groups having aliphatic, alicyclic, aryliphatic, and / or aromatic bonds, such as 1,4-diisocyanate butane (BDI), 1,5-diisocyanate pentane (PDI), 1,6-diisocyanate hexane (HDI), 2-methyl-1,5-diisocyanate pentane, 1,5-diisocyanate 2,2-dimethylpentane, 2,2,4- or 2,4,4-trimethyl-1,6-diisocyanate hexane, 1,10-diisocyanate decane, 1,3- and 1,4-diisocyanate cyclohexane, 1,4-diisocyanate cyclohexane, etc. Cyanide-3,3,5-trimethylcyclohexane, 1,3-diisocyanate-2-methylcyclohexane, 1,3-diisocyanate-4-methylcyclohexane, 1-isocyanate-3,3,5-trimethyl-5-isocyanate-methylcyclohexane (isophorone diisocyanate; IPDI), 1-isocyanate-1-methyl-4(3)-isocyanate-methylcyclohexane, 2,4'- and 4,4'-diisocyanate-dicyclohexylmethane (H12MDI), 1,3- and 1,4-bis(isocyanate-methyl)cyclohexane, bis(isocyanate-methyl)-... Borneol (NBDI), 4,4'-diisocyanate-3,3'-dimethyldicyclohexylmethane, 4,4'-diisocyanate-3,3',5,5'-tetramethyldicyclohexylmethane, 4,4'-diisocyanate-1,1'-bis(cyclohexyl), 4,4'-diisocyanate-3,3'-dimethyl-1,1'-bis(cyclohexyl), 4,4'-diisocyanate-2,2',5,5'-tetramethyl-1,1'-bis(cyclohexyl), 1,8-diisocyanate-p-menthane, 1,3-diisocyanate-adamantane, 1 3-Dimethyl-5,7-diisocyanate-adamantane, 1,3- and 1,4-bis(isocyanate-methyl)benzene (phenylene diisocyanate; XDI), 1,3- and 1,4-bis(1-isocyanate-1-methylethyl)benzene (TMXDI) and bis(4-(1-isocyanate-1-methylethyl)phenyl)carbonate, 2,4- and 2,6-diisocyanate-toluene (TDI), 2,4'- and 4,4'-diisocyanate-diphenylmethane (MDI), 1,5-diisocyanate-naphthalene, and any mixtures of such diisocyanates.Other equally applicable diisocyanates can be found, for example, Justus Liebigs Annalen der Chemie, Vol. 562 (1949), pp. 75-136.

[0034] Suitable monomeric monoisocyanates that may be optionally used in polyisocyanate component A include, for example, n-butyl isocyanate, n-pentyl isocyanate, n-hexyl isocyanate, n-heptyl isocyanate, n-octyl isocyanate, undecyl isocyanate, dodecyl isocyanate, tetradecyl isocyanate, hexadecyl isocyanate, stearyl isocyanate, cyclopentyl isocyanate, cyclohexyl isocyanate, 3- or 4-methylcyclohexyl isocyanate, or any mixture of such monoisocyanates. Examples of monomeric isocyanates with an isocyanate functionality greater than 2 that may be optionally added to polyisocyanate component A include 4-isocyanomethyloctane-1,8-diisocyanate (triisocyanate nonane; TIN).

[0035] In a preferred embodiment of the invention, polyisocyanate component A contains up to 30% by weight, particularly up to 20% by weight, up to 15% by weight, up to 10% by weight, up to 5% by weight, or up to 1% by weight of aromatic polyisocyanate, respectively, based on the total weight of polyisocyanate component A. As used herein, "aromatic polyisocyanate" refers to a polyisocyanate having at least one aromatic-bonded isocyanate group. An aromatic-bonded isocyanate group is understood to refer to an isocyanate group attached to an aromatic hydrocarbon group.

[0036] In a particularly preferred embodiment of the invention, polyisocyanate component A is composed of polyisocyanates having only aliphatic and / or alicyclic bonded isocyanate groups to a degree of at least 90% by weight, more preferably 95% by weight, even more preferably 98% by weight, and most preferably 99% by weight (based on the total weight of polyisocyanate component A, respectively). Practical experiments have shown that polyisocyanate component A, in which the isocyanate contains only aliphatic and / or alicyclic bonded isocyanate groups, yields particularly good results.

[0037] Aliphatic or alicyclic bonded isocyanate groups are understood to refer to isocyanate groups bonded to aliphatic or alicyclic hydrocarbon groups, respectively.

[0038] In another particularly preferred embodiment of the method of the present invention, a polyisocyanate component A consisting of or containing one or more oligomeric polyisocyanates, wherein the one or more oligomeric polyisocyanates have only aliphatic and / or alicyclic bonded isocyanate groups.

[0039] In a particularly preferred embodiment of the method of the present invention, a polyisocyanate component A consisting of or containing one or more oligomeric polyisocyanates is used, wherein the one or more oligomeric polyisocyanates are formed based on 1,4-diisocyanate butane (BDI), 1,5-diisocyanate pentane (PDI), 1,6-diisocyanate hexane (HDI), isophorone diisocyanate (IPDI), or 4,4'-diisocyanate dicyclohexylmethane (H12MDI) or mixtures thereof.

[0040] Ionic or potentially ionic hydrophilic compounds B To ensure that the reaction products of this invention have the acid value defined above, the use of ionic or potentially ionic hydrophilic groups is essential. Alternatively, compounds having nonionic hydrophilic groups may also be used, provided that the appropriate proportions are chosen to achieve the desired acid value according to this invention.

[0041] Ionic or potentially ionic hydrophilic compound B contains at least one isocyanate reactive group. The term "isocyanate reactive group" is understood to refer to all functional groups containing at least one Zelevitzinov active hydrogen atom. This term preferably refers to hydroxyl, amino, and thiol groups, more preferably hydroxyl.

[0042] The ionic or potentially ionic hydrophilic compound is preferably a hydroxycarboxylic acid or an aminocarboxylic acid, more preferably monohydroxycarboxylic acid and dihydroxycarboxylic acid, monoaminocarboxylic acid and diaminocarboxylic acid, monohydroxysulfonic acid and dihydroxysulfonic acid, monoaminosulfonic acid and diaminosulfonic acid, and monohydroxyphosphonic acid and dihydroxyphosphonic acid or monoaminophosphonic acid and diaminophosphonic acid and their salts. More preferably, the compound is selected from at least one of the following: dimethylolpropionic acid, dimethylolbutyric acid, hydroxypentanoic acid, N-(2-aminoethyl)alanine, 2-(2-aminoethylamino)ethanesulfonic acid, ethylenediaminepropionic acid, ethylenediaminebutyric acid, 1,2- and 1,3-propanediamineethanesulfonic acid, malic acid, citric acid, glycolic acid, lactic acid, glycine, alanine, taurine, lysine, 3,5-diaminobenzoic acid, polyether sulfonate, adducts of sodium bisulfite and but-2-ene-1,4-diol, and alkali metal salts and ammonium salts of the above compounds. More preferably, compound B is at least one compound selected from 2,2-dimethylolacetic acid, 2,2-dimethylolbutyric acid, 2,2-dimethylolvalerate, dihydroxysuccinic acid, or α,Ω-diaminovalerate. Particularly preferred compound B is 2,2-dimethylolpropionic acid. Alternatively, a monohydroxy functional compound having at least one carboxylic acid group, such as hydroxypentanoic acid or hydroxydecanoic acid, may be used. A mixture of two or more of the above compounds is also preferred. Less preferably, a polyhydroxy acid, particularly gluconic acid, may also be used as compound B.

[0043] The aforementioned acids are converted into their respective salts by reaction with neutralizing agents, such as triethylamine, ethyldiisopropylamine, dimethylcyclohexylamine, dimethylethanolamine, ammonia, N-methylmorpholine, NaOH, LiOH, and / or KOH. For neutralizing agents that do not react with isocyanates, this can be carried out at any point in the preparation process, up to the dispersion step. The degree of neutralization, i.e., the equivalent number of the neutralizing agent, can be from 30% to 150%, preferably from 50% to 110%, based on the equivalent number of potential ionic groups.

[0044] The optional nonionic hydrophilic compound is a polyepoxide polyether alcohol or a polyepoxide polyether amine, particularly a polyepoxide polyether or a mixture of polyepoxide polyethers, wherein the epoxide units consist of ethylene oxide units to a degree of at least 30 mol%.

[0045] Radiation-curable component C The term "radiation-curable component C" refers to all compounds present in the reaction mixture containing two or more olefinic unsaturated groups. These olefinic unsaturated groups are preferably (meth)acrylate groups. Preferably, component C contains at least 80 mol%, more preferably at least 90 mol%, and more preferably at least 95 mol% of molecules with a molecular weight of 170 to 800 g / mol. However, due to production-related reasons, it is possible that individual molecules may undergo oligomerization during synthesis, resulting in component C potentially containing a small proportion of larger molecules.

[0046] According to the present invention, a mixture of two or more compounds having the characteristics defined herein may be used as radiation-curable component C.

[0047] In a preferred embodiment of the invention, the radiation-curable component C comprises at least one (meth)acrylate containing an alcohol selected from the group consisting of ethane-1,2-diol, propane-1,2-diol, propane-1,3-diol, butane-1,4-diol, butane-1,3-diol, pentane-1,5-diol, hexane-1,6-diol, decane-1,10-diol, dodecane-1,12-diol, butane-1,3-diol, 2,2-dimethylpropane-1,3-diol, 2-methylpropane-1,3-diol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, 1,4- and 1,6-dihydroxymethylcyclohexane, glycerol, trimethylolpropane, trimethylolethane, pentaerythritol, diglycerol, bis(trimethylolpropane), bis(pentaerythritol), sorbitol, and alkoxylated derivatives of the above alcohols.

[0048] In a particularly preferred embodiment of the invention, the radiation-curable component C comprises at least one (meth)acrylate containing an alcohol selected from pentaerythritol, bis(trimethylolpropane), bis(pentaerythritol), and alkoxylated derivatives of the above alcohols.

[0049] In another particularly preferred embodiment, component C consists of one or more compounds as defined in the preceding paragraph to a degree of at least 60% by weight, preferably at least 80% by weight, more preferably at least 90% by weight, and especially preferably at least 95% by weight, based on the total weight of component C.

[0050] In another preferred embodiment of the invention, compound C is hydroxyl-functionalized. If component C is hydroxyl-functionalized, its OH value according to the invention is 1 to 60, preferably 5 to 60 mg KOH / g, preferably determined according to DIN EN ISO 4629-2:2015-02. For the advantageous properties of the aqueous composition, it is important to adhere to the upper limit of 60 mg KOH / g.

[0051] Catalyst D To accelerate the reaction, the reaction mixture in a preferred embodiment of the invention further comprises catalyst D. In principle, any catalyst suitable for accelerating the reaction is any catalyst that catalyzes the reaction of isocyanate groups with hydroxyl groups. These catalysts are known to those skilled in the art or can be found in existing literature on the synthesis of carbamates. Tertiary amines, tin compounds, zinc compounds, zirconium compounds, copper compounds and / or bismuth compounds are particularly suitable, with triethylamine, ethyldiisopropylamine, dimethylcyclohexylamine, N-methylmorpholine, 1,4-diazabicyclo[2.2.2]octane, dibutyltin oxide, dibutyltin dilaurate, 2-ethylhexyltin octanoate (II), and 2-ethylhexylbismuth octanoate (III) being preferred. Zinc salts, titanium salts, and molybdenum salts are also suitable. Suitable amounts are, for example, from 0.002% to 2.5% by weight, preferably from 0.01% to 1% by weight, based on the total mass of the reaction mixture. The reaction can also be carried out without the use of a catalyst.

[0052] Preparation method The preparation of the dispersion of the present invention is carried out at a temperature of 20°C to 150°C, preferably 25°C to 75°C. Components A, B, and C, and optionally D, may be present at the start of the reaction in a diluted form with an inert solvent. The inert solvent may also be added at any of the reaction steps. The inert solvent optionally used may subsequently be removed by distillation. Preparation may be carried out without the use of an inert solvent, but it is preferred to prepare it in an organic solvent. It is preferred to prepare it in 3% to 50% by weight, more preferably 5% to 25% by weight, of an inert solvent, particularly acetone, based on the total mass of the reaction mixture, and the solvent is subsequently removed by distillation after the preparation of the dispersion or during the dispersion step.

[0053] In a preferred embodiment of the invention, the aqueous composition is prepared without chain extension of the reaction products contained therein. This means that the molecular weight is not increased by reacting free isocyanate groups that may remain after the reactions of components A, B, and C with compounds containing two or more hydroxyl, thiol, or amino groups per molecule. Also preferably, no other polyisocyanates that would cause crosslinking of any remaining free hydroxyl groups are added to the final reaction product.

[0054] Aqueous acrylate dispersion In another embodiment, the present invention relates to an aqueous coating composition comprising at least one aqueous composition containing a product as defined above in this application as component (i) and at least one polyacrylate dispersion or at least one polyurethane dispersion or a mixture of at least one polyacrylate dispersion and at least one polyurethane dispersion as component (ii).

[0055] In a preferred embodiment, the solid weight percentage of component (i) is 5% to 60% by weight, preferably 10% to 50% by weight, more preferably 20% to 30% by weight, based on the total mass of all solids in (i) and (ii).

[0056] In a preferred embodiment of the invention, the binder in the coating composition comprises, to a degree of at least 30% by weight, components (i) and (ii), based on their total weight. Here, "binder" is understood to refer to various compounds or compositions that impart strength to the coating, particularly polymers with a number average molecular weight of at least 5000 g / mol. The binder component particularly excludes pigments, UV stabilizers, catalysts, rheology modifiers, and inert solvents.

[0057] polyacrylate dispersion Suitable component (ii) is, in principle, all nonionic and anionic polyacrylate emulsion polymers known in the art. Such polymers are typically prepared by polymerization of acrylates and / or methacrylates containing alkanoates with 1 to 10 carbon atoms. The polyacrylate emulsion polymer may contain up to 60% by weight of styrene, up to 20% by weight of vinyl esters, and / or up to 10% by weight of water-soluble monoolefin unsaturated comonomers. Preferred water-soluble monoolefin unsaturated comonomers are acrylic acid, methacrylic acid, itaconic acid, acrylamide, and methacrylamide. Polymerization is preferably carried out in an aqueous emulsion at 30 to 95°C in the presence of a free radical-forming polymerization initiator, such as a water-soluble peroxide, like a persulfate, such as ammonium persulfate or potassium persulfate. Typically, the amount of anionic and / or nonionic emulsifier is from 0.1% to 5% by weight. Such polymers and their preparation are described, for example, in EP0065162B1 or in U. Poth et al., Acrylic Resins, Vincentz Network, (2011). Self-crosslinking nonionic and anionic polyacrylate emulsion polymers as described in D. Mestach, FATIPEC Congress (2000), Vol. 25, pp. 347-361 are also applicable.

[0058] polyurethane dispersion Anionic one-component polyurethane dispersions are also suitable as component (ii). These are high molecular weight nonfunctional polyurethane dispersions known in the art. They preferably comprise reaction products of polyisocyanates with polyether polyols, polycarbonate polyols and / or polyester polyols, and at least one hydrophilic compound defined above as component B. The number average molecular weight of these reaction products is preferably from 50,000 to 200,000 g / mol.

[0059] Anionic UV-curable polyurethane dispersions are also suitable as components (ii). Such dispersions are described in detail in U. Meier-Westhues, Polyurethanes, Vincentz Network (2007).

[0060] The research upon which this invention is based indicates that aqueous compositions containing the reaction products of this invention are well suited for improving the application performance of the aforementioned materials by mixing with polyacrylate dispersions and / or polyurethane dispersions, even if the proportion of the aqueous composition containing the reaction products of this invention in the mixture is significantly less than that of the polyacrylate dispersions and / or polyurethane dispersions.

[0061] Therefore, in another embodiment, the present invention relates to the use of aqueous compositions containing the reaction products of the present invention, as further defined above, for improving the application technical performance of polyacrylate dispersions and / or polyurethane dispersions.

[0062] The preferred improved application performance characteristics are anti-blocking and / or chemical resistance. Preferred chemical resistance characteristics include resistance to iodine, ethanol, red wine, coffee, or water.

[0063] By mixing conventional polyacrylate dispersions and polyurethane dispersions with the reaction products of this invention, coating compositions with significantly superior application performance compared to pure dispersions and reaching the level of two-component polyurethane dispersions can be obtained. Unlike known two-component compositions, the mixtures of this invention have no shelf life because the reaction products of this invention do not contain free isocyanate groups.

[0064] In another embodiment, the present invention relates to coatings obtained or available from the aqueous compositions of the present invention, the aqueous compositions comprising the reaction products of the present invention as defined above.

[0065] The mixture of the reaction product of this invention with a polyurethane dispersion is particularly suitable for improving the abrasion resistance of plastic floor coverings, especially those containing or composed of polyvinyl chloride.

[0066] The mixture of the reaction product of this invention with a polyacrylate dispersion is particularly suitable for improving the chemical resistance of wood coatings, especially resistance to staining substances. Simultaneously, anti-blocking properties are also improved. Similar to polyacrylate dispersions, polyurethane-polyacrylate hybrid dispersions are also suitable as component (ii). A well-suited polyurethane-polyacrylate hybrid dispersion is described in CR Hegedus and KA Kloiber, Journal of Coatings Technology, Vol. 68, No. 860, September 1996, pp. 39-48.

[0067] In yet another embodiment, the present invention relates to coatings obtained or available from an aqueous composition as defined above, comprising at least one component (i) and at least one component (ii).

[0068] Preferably, the coating is present on a surface selected from wood, plastic, metal, and composite materials. The plastic is preferably polyvinyl chloride (PVC), and more preferably a floor covering comprising or composed of PVC.

[0069] The following examples are for illustrative purposes only and should not be construed as limiting the scope of the claims in any way. Example

[0070] raw material DPPA – Dipentaerythritol pentaacrylate, for example, available from Miwon Specialty Chemical Co. under the trade name Miramer M 500. DPHA – Dipentaerythritol hexaacrylate, available for example by Miwon Specialty Chemical Co. under the trade name Miramer M 600 or by Covestro AG under the trade name AgiSyn 2830L. PETiA – Pentaerythritol triacrylate, for example, available from Covestro AG under the trade name AgiSyn 2884. Laromer PE 44 F – Liquid polyester acrylate, free of reactive diluents, available from BASF SE. Desmodur N 3600 – Low viscosity HDI trimer, approximately 23% NCO, Covestro AG Desmodur N 3300 – HDI trimer, approximately 22% NCO, Covestro AG HDI – Hexamethylene diisocyanate IPDI – Isophorone diisocyanate DBTL – Dibutyltin Dilaurate Borchi Kat 24 – Bismuth Catalyst, Borchers GmbH Kosmos T9 – Tin Di(2-Ethylhexanoate), Evonik Operations GmbH DMPS = 2,2-bis(hydroxymethyl)propionic acid HPS = 2,2-dimethyl-3-hydroxypropionic acid Bayhydrol A 2846 – Self-crosslinking hydroxyl-functionalized polyacrylate dispersion, Covestro AG Picassian AC-169 – Aqueous anionic self-crosslinking styrene-acrylic copolymer emulsion, Stahl Holdings BV Carboset CA7160 RC – Styrene-Acrylic Copolymer Emulsion, Lubrizol Bayhydrol UV 2282 – UV-curable waterborne polyurethane dispersion, Covestro AG Bayhydrol UV 2720 / 1 – UV-curable waterborne polyurethane dispersion, Covestro AG.

[0071] method Viscosity measurements were performed using a Physica MCR 51 rheometer from Anton Paar Germany GmbH (DE) according to DIN EN ISO 3219:1994-10.

[0072] The NCO content was determined by titration according to DIN EN ISO 11909:2007-05.

[0073] Non-volatile components (nfA) were determined by circulating air oven according to DIN EN ISO 3251:2008-06 Method B (1 g / 1 h / 125 °C).

[0074] The mean particle size (MTG) was determined using a Malvern (DE) Zetasizer Nano according to DIN ISO 13321:2004-10.

[0075] pH values ​​were determined using a pH meter according to DIN ISO 976:2008-07, diluted with distilled water at a ratio of 1:4.

[0076] Flow time – measured according to DIN EN ISO 2431:2011 using a 4 mm cup at 23°C.

[0077] Gloss and haze values ​​are measured on black acrylic glass according to DIN EN ISO 2813:2015, unless otherwise stated in the text.

[0078] Chemical resistance was determined on melamine-faced MDF plates according to DIN EN 68861-1 1B 2011_01 and IKEA IOS-MAT-066 R2&R0, unless otherwise stated in the text. Immediate damage or post-recycling damage was recorded, unless otherwise stated in the text. All tests and assessments were conducted according to DIN EN 12720 2014_2: 5 - no change, 1 - significant change.

[0079] Pencil hardness is determined on glass according to DIN EN ISO 15184 2020_05, unless otherwise stated in the text.

[0080] The pendulum hardness was measured on glass after 1 day or 7 days according to König DIN EN ISO 1522: 2022.

[0081] Abrasion resistance was determined according to ASTM D 4060-1 (Taber abrasion tester, 1000 g weight CS 10 grinding wheel, 1000 revolutions).

[0082] Anti-adhesion was determined as follows: Coated substrates (same size, melamine-faced MDF boards) were stacked together after irradiation, with the coated sides in contact to form a cross shape. A weight was placed on top, with the load determined by the surface area of ​​the substrate and the mass of the weight. After a certain period of time, the weight was removed, and the components were attempted to be manually separated from each other. The required force and the resulting surface damage were assessed.

[0083] force: A - These parts cannot be separated B - Very strong force to achieve separation C - with great force, to achieve separation D - Average force, used to achieve separation E - Light force, to achieve separation F - All components are completely separated damage: 0 - Unable to separate these parts 1 - Significant damage 2 - Minor damage 3 - Visible markers 4 - Visible light spots 5 - No damage.

[0084] Example 1 (according to the present invention) 69.13 g DPPA, 212.50 g DPHA, 68.50 g Desmodur N 3600, 0.18 g DBTL 24, and 65 g acetone were pre-loaded into a reactor, heated to 60°C, and stirred until a homogeneous mixture was formed. Then, 6.70 g DMPS and 11.80 g HPS were added, and stirring continued at 60°C until the NCO content reached <0.3% by weight. Subsequently, 15.00 g triethylamine was added to the mixture. After another 15 minutes, the mixture was dispersed with 481.68 g of water. Finally, acetone was removed by vacuum distillation. A dispersion with the following characteristic data was obtained: nfA 48% by weight Flow time (DIN 4 mm, 23°C): 33 seconds pH value 7.3 MTG 69 nm.

[0085] Example 2 (according to the present invention) 1082.17 g DPPA, 156.65 g Desmodur N 3600, 92.61 g HDI, 0.74 g Borchikat 24, and 96 g acetone were pre-loaded into a reactor, heated to 60°C, and stirred until a homogeneous mixture was formed. Then, 82.08 g DMPS followed by 223 g acetone were added to the mixture, and stirring continued at 60°C until the NCO content reached <0.3% by weight. Subsequently, 59.44 g triethylamine was added to the mixture. After another 15 minutes, the mixture was dispersed with 1871.80 g water. Finally, the acetone was removed by vacuum distillation. A dispersion with the following characteristic data was obtained: nfA 43% by weight Flow time (DIN 4 mm, 23°C): 32 seconds pH value 7.9 MTG 41 nm.

[0086] Example 3 (according to the present invention) 530.04 g DPPA, 81.90 g Desmodur N 3300, 45.36 g HDI, and 0.36 g Borchikat24 were pre-loaded into a reactor, heated to 60°C, and stirred until a homogeneous mixture was formed. Then, 40.20 g DMPS and subsequently 156 g acetone were added to the mixture, and stirring continued at 60°C until the NCO content reached 0.2% by weight. Next, 25.80 g triethylamine was added to the mixture. After another 15 minutes, the mixture was dispersed with 916.80 g water. Finally, the acetone was removed by vacuum distillation. A dispersion with the following characteristic data was obtained: nfA 40% by weight Viscosity (23℃, d=40 / s): 93 mPas pH value 7.8 MTG 94 nm.

[0087] Example 4 (according to the present invention) 672.50 g DPHA, 78.49 g Desmodur N 3300, 43.47 g HDI, and 0.35 g Borchikat24 were pre-loaded into a reactor, heated to 60°C, and stirred until a homogeneous mixture was formed. Then, 38.53 g DMPS and subsequently 150 g acetone were added to the mixture, and stirring continued at 60°C until the NCO content reached 0.2% by weight. Next, 26.45 g triethylamine was added to the mixture. After another 15 minutes, the mixture was dispersed with 954.50 g water. Finally, the acetone was removed by vacuum distillation. A dispersion with the following characteristic data was obtained: nfA 47% by weight Viscosity (23℃, d=40 / s): 107 mPas pH value 7.4 MTG 67 nm.

[0088] Example 5 (according to the present invention) 658.78 g DPHA, 68.25 g Desmodur N 3300, 37.80 g HDI, and 0.42 g Borchikat24 were pre-loaded into a reactor, heated to 60°C, and stirred until a homogeneous mixture was formed. Then, 33.50 g DMPS and subsequently 130 g acetone were added to the mixture, and stirring continued at 60°C for 15 minutes. Next, 23.00 g triethylamine was added to the mixture, and stirring continued at 60°C until the NCO content reached <0.2% by weight. The mixture was then dispersed with 830.00 g of water. Finally, acetone was removed by vacuum distillation. A dispersion with the following characteristic data was obtained: nfA 50% by weight Viscosity (23℃, d=40 / s): 150 mPas pH value 7.5 MTG 90 nm.

[0089] Comparative Example 6 187.10 g Laromer PE 44F, 13.74 g DMPS, 0.28 g DBTL, 23.55 g HDI, 47.67 g IPDI, and 65 g acetone were preloaded into a reactor, heated to 60°C, and stirred at 60°C until the NCO content reached 1.7% by weight. The reaction mixture was then cooled to 50°C. Additionally, 116.79 g DPHA was added and stirred for 15 minutes. Next, 9.55 g triethylamine was added to the mixture and stirred for 15 minutes. The mixture was then dispersed with 591.24 g water and chain-extended with a mixture of 3.42 g ethylenediamine / 11.5 g water. Finally, acetone was removed by vacuum distillation. A dispersion with the following characteristic data was obtained: nfA 42% by weight Viscosity (23°C, d=40 / s): 35 mPas pH value 8.1 MTG 89 nm.

[0090] Comparative Example 7 224.46 g PETiA, 17.63 g DMPS, and 149.98 g dicyclohexylmethane-4,4'-diisocyanate were pre-loaded into a reactor and heated to 50 °C. 0.11 g Kosmos T9 catalyst was added in two portions with stirring. The reaction mixture was stirred at 60 °C until the NCO content reached 4.5 wt%. The reaction mixture was then cooled to 50 °C. Additionally, 13.32 g triethylamine was added and stirred for 15 minutes. The mixture was then dispersed in 556.80 g water and chain extended with 52.60 g of 64% hydrazine solution. After adjusting the solids content to approximately 40 wt%, a dispersion with the following characteristics was obtained: nfA 40% by weight Viscosity (23°C, d=40 / s): 20 mPas pH value 8.5 MTG 65 nm.

[0091] Comparative Examples 8-10 and Example 11 of the present invention: A conventional polyacrylate dispersion (Bayhydrol A 2846) was added to the DPPA and the PUD dispersion in Example 2 of this invention:

[0092] The mixture was manually mixed using a wooden scraper. The resulting dispersions were stored at room temperature and 40°C. The dispersions of Comparative Examples 8 to 10 showed significant phase separation one day after mixing, while the dispersion of the present invention in Example 11 remained homogeneous and showed no change in appearance after two weeks at 40°C. These results confirm that the dispersion of the present invention in Example 2 can be easily and conveniently added to commercially available polyacrylate dispersions, as opposed to reactive diluents that do not contain the reaction products of the present invention.

[0093] Application technology tests were conducted on the dispersions of the present invention in Example 3 and the comparative dispersions in Examples 6 and 7 compared with the commercially available polyurethane dispersion Bayhydrol UV 2282 using the formulations recorded in Tables 1 and 2.

[0094] Table 1. Composition of white matte coatings based on the dispersions in Examples 3, 6, and 7, and the commercially available UV dispersion Bayhydrol UV 2282. Tego® Airex 902W – Defoamer, Evonik Acematt® TS-100 – Matting Agent, Evonik Ceraflour® 929 – Wax, BYK Chemie Omnirad® 500 – Photoinitiator, IGM Resins Omnirad® 819 – Photoinitiator, IGM Resins Tego® Disperse 660C – Dispersant, Evonik.

[0095] Table 2. Composition of the pigment paste used in Examples 12 to 15 Apply the coating to the melamine-faced MDF board (single layer, 120g / m² thickness) using a manual airspray gun. 2 The sample was placed on a surface and ventilated for 10 minutes at 22℃ / 50% humidity, then dried at 45℃ for 20 minutes. Finally, it was irradiated with ultraviolet light (mercury lamp, 120W / cm²). 2 + Gallium lamp, 120W / cm 2 (The conveyor belt speed was approximately 7 m / min). The irradiated plates were conditioned at 22°C for 16 hours before application technology testing. The application technology test results are listed in Table 3.

[0096] As shown in Table 3, the composition of the present invention in Example 3 is able to produce a hard coating with a silky matte finish (Example 12), and its chemical resistance even exceeds that of conventional UV polyurethane dispersions (Example 13), as well as the dispersions of non-inventive chain-extended Examples 6 and 7 (Examples 14 and 15).

[0097] The dispersion in Example 5 was also formulated into a varnish as shown in Table 4 and its application technology was tested in comparison with a varnish based on Bayhydrol UV 2282.

[0098] Table 4. Composition of varnishes based on the dispersion in Example 5 and the commercially available UV dispersion Bayhydrol UV 2282 Omnirad 1173 – Photoinitiator, IGM Resins Byk 348 – Silicone surfactant for water-based paints, Byk Chemie AMP 90 – Buffer Solution, Angus Chemical Co. Apply the coating to the appropriate substrate using a frame scraper (single layer, wet coat thickness 150 µm), ventilate at 23°C / 45% humidity for 10 minutes, dry at 50°C for 15 minutes, and then irradiate with ultraviolet light (mercury lamp, 80 W / cm²). 2 (The conveyor belt speed was approximately 5 m / min). The irradiated plates were conditioned at 23°C for 16 hours before application technology testing. The application technology test results are listed in Table 5.

[0099] Table 5. Test results of the formulations in Examples 16 and 17 .

[0100] The test results of the varnish formulation application technology shown in Table 5 confirm that the composition of the present invention in Example 5 has improved hardness, anti-blocking properties and better chemical resistance than the commercially available polyurethane dispersion in Example 17, even in the varnish formulation (Example 16).

[0101] The dispersions of the present invention in Examples 1 and 2 were also tested mixed with conventional non-UV functionalized polyacrylate dispersions. The aim was to improve performance by adding a small amount of the dispersions of the present invention. The coatings were applied to the respective substrates (single layer, wet layer thickness 150 µm, for pendulum hardness and anti-blocking tests) using a frame scraper, aerated at 23°C / 45% humidity for 10 minutes, dried at 50°C for 15 minutes, and then irradiated with UV radiation (mercury lamp, 80 W / cm²). 2(The conveyor belt speed was approximately 5 m / min). To determine the chemical resistance on beech wood, two layers were applied, with the wet layer being 150 µm thick. The irradiated boards were conditioned at 23°C for 16 hours prior to the application technology tests. Substrates with the comparative coatings from Examples 24 and 31 were tested after conditioned at 23°C for 7 days. The application technology test results are listed in Table 6.

[0102] The following conclusions can be drawn from the data in Table 7: When combined with Picassian AC-169, the product of this invention exhibits excellent chemical resistance, significantly improved anti-blocking properties, and approximately 10% higher hardness compared to the unmodified polyacrylate dispersion. When combined with Carboset CA 7160, the product of this invention also exhibits improved anti-blocking properties and chemical resistance compared to the unmodified dispersion.

[0103] The dispersions in Examples 3 and 7 of this invention were also tested in combination with the conventional non-UV functionalized polyacrylate dispersion Bayhydrol A 2846. The coatings were applied to the respective substrates (single layer, 180 µm thickness) using a frame scraper, aerated at 23°C / 45% humidity for 10 minutes, dried at 50°C for 15 minutes, and then irradiated with UV radiation (mercury lamp, 80 W / cm²). 2 (The conveyor belt speed was approximately 5 m / min). To determine chemical resistance on beech wood, two layers were applied, with a wet layer thickness of 180 µm. The irradiated boards were conditioned at 23°C for 24 hours prior to application technology testing. The formulation and application technology test results are listed in Table 8.

[0104] Table 8. Composition and test results of varnishes based on mixtures of the dispersions in Examples 3 and 7 with conventional PAC dispersions.

[0105] As can be seen from Table 8, adding a small amount (20-30% by weight) of the inventive dispersion in Example 3 and the comparative dispersion in Example 7 to a conventional polyacrylate dispersion (e.g., Bayhydrol A 2846) significantly improved its chemical resistance. This is particularly applicable to resistance to dyeing substances. However, only the inventive dispersion in Example 3 also significantly improved anti-blocking properties.

[0106] The dispersions of the present invention can also be used to improve the performance of commercially available UV-curable polyurethane dispersions. Table 9 provides examples of such applications.

[0107] The dispersions shown in Table 9 were applied to the corresponding substrates (monolayer, 36 µm thickness) using a spiral scraper, aerated at 23°C / 45% humidity for 10 minutes, dried at 50°C for 15 minutes, and then irradiated with ultraviolet light (mercury lamp, 80 W / cm²). 2 The conveyor belt speed is approximately 15 m / min.

[0108] Table 9. Composition and test results of the varnish based on the mixture of the dispersion in Example 2 and conventional UV polyurethane dispersion. DISPERBYK 191 – Dispersant for water-based paint systems, Byk Chemie DEUTERON MK – Matting Agent, Deuteron GmbH BYK-093 – Silicone-containing defoamer for water-based paint systems, Byk Chemie ESACURE KIP 100 F – Photoinitiator, IGM Resins TAFIGEL PUR 45 – Associative Thickener, Münzing Chemie.

[0109] Table 9 confirms that the dispersion of the present invention in Example 2 significantly improves the resistance to strong staining substances in conventional UV-cured coatings even in small amounts (20-30% by weight). The abrasion resistance of coatings based on this mixture is also significantly higher. The dispersion of the present invention in Example 2 is also well-compatible with Bayhydrol UV dispersion liquid, as evidenced by its good gloss value and even better haze value. This combination of properties offers technical advantages, especially in the field of PVC floor coatings.

[0110] Comparative Example 32 (Contrast) Example 1b of US 2018 / 0244948 was replicated, wherein the proportion of component B (dipropylene glycol diacrylate) was increased to achieve a double bond density of 6 mol / kg (6 mmol / g).

[0111] The following ingredients were added: 19.63 g dimethylolpropionic acid, 90.87 g 2-hydroxyethyl acrylate, 20.25 g polyethylene glycol monoethyl ether MPEG 1000 (TCI Deutschland GmbH), 9.96 g cyclohexane-1,4-diethanol, 14.47 g Baycoll AD1225 (Covestro AG, Leverkuksen), 29.74 g hexamethylene diisocyanate trimer (Desmodur N3300, Covestro AG, Leverkuksen), 43.69 g 4,4'-diisocyanate dicyclohydroxymethane (DesmodurW, Covestro AG, Leverkuksen), 201.18 g isophorone diisocyanate trimer (Vestanat T 1890 / 100, Evonik Industries, Essen), 0.21 g 3,5-di-tert-butyl-4-hydroxytoluene, and 0.09 g... 4-Oxypiperidinol (4-hydroxy-TEMPO) was added to a stirred tank and diluted with 108 g of methyl ethyl ketone. After adding 0.30 g of zinc neodecanoate, the mixture was heated to 80°C. The reaction progress was tracked by measuring the NCO content. When the NCO content was <0.40 wt%, the mixture was further diluted with 1000 g of acetone. The amount of acetone was adjusted according to the increase in solids. Then, 850 g of Laromer DPGDA (dipropylene glycol diacrylate) was added as component B. The amount of component B was selected such that the double bond density of the final dispersion was 6 mmol / g. The resulting mixture was neutralized by adding 41.02 g of sodium hydroxide aqueous solution (10 wt%) and dispersed in 1900 g of deionized water. The amount of water was adjusted according to the increase in solids to obtain a dispersion with a solids content of 40 wt%. The solvent was then removed by distillation. A dispersion with the following characteristic data was obtained: nfA (calculated value) 40% by weight Viscosity (23℃) 18 mPas MTG: 18 nm Because Laromer DPGDA forms an azeotrope with water, the non-volatile component (nfA) in the dispersion cannot be measured and calculated.

[0112] After two weeks of storage at room temperature, the characteristic data were measured again. The average particle size increased to 349 nm and still exhibited a bimodal distribution; the viscosity increased to 66 mPas. These changes in characteristic data indicate that the dispersion is not resistant to storage. Furthermore, the extremely high average particle size (initially, but particularly pronounced after storage) suggests that the dispersion is unsuitable for use in coatings. Nevertheless, paint technology tests were performed on the dispersion.

[0113] Similar to Examples 12, 13, 14 and 15 shown in Table 1, paint technology tests were performed on the comparative dispersions in formulations with added white pigment: Table 10: Reproduction of Example 1b in US 2018 / 0244948

[0114] The paint was applied and cured as described in the above examples. Test results are similar to those in Table 3 and are shown in Table 12 below. Overall, the chemical resistance was lower than that of Example 12 of the present invention. It is also noteworthy that the comparative dispersion did not form a closed film at all, and the surface was covered with gel particles. Furthermore, despite the high double bond density, the film exhibited very low pendulum hardness.

[0115] Comparative dispersions were also tested in varnish formulations similar to those in Table 4 (Examples 16 and 17): Table 11: Formulas as varnish .

[0116] The varnish was applied and cured as described therein. Test results are shown in Table 13. All films containing the comparative dispersions showed bubbling and slightly lower tolerance after stress. However, the films containing the comparative dispersions showed particularly poor anti-blocking properties compared to the dispersions of the present invention.

[0117] Table 12: Comparative test results of application technology of dispersions Table 13: Further results of comparative dispersion application technology tests Comparative Example 33 (Contrast) The difference between Example 1b of US 2018 / 0244948 and the method for preparing the dispersion of the present invention lies in the timing of the addition of the hydroxyl-functionalized radiation-curable component C (component B in US 2018 / 0244948). Therefore, the timing of the addition of this component was investigated to determine whether it has a technical impact.

[0118] Example 5 of the present invention is an improvement by adding DPHA after carbamate esterification, similar to Example 1 of US 2018 / 0244948. Therefore, this component is not part of the original reaction mixture.

[0119] 33.50 g DMPS, 68.25 g Desmodur N 3300 (Covestro Deutschland AG, Leverkusen), 37.80 g HDI, 0.42 g Borchikat 24 (Borchers GmbH, Langenfeld), and 108 g methyl ethyl ketone were preloaded into a reactor, heated to 80°C, and stirred. A homogeneous mixture was formed, but it quickly turned into a solid and could not be dissolved even after the addition of 130 g acetone. Therefore, a dispersion could not be prepared.

[0120] Therefore, it is essential that component C is already present in the reaction mixture at the start of the reaction and cannot be added subsequently.

Claims

1. An aqueous composition comprising a product obtained or obtainable from the reaction of a reaction mixture comprising a) a polyisocyanate component A having an average isocyanate functionality of at least 2.2 NCO groups per molecule; b) at least one ionic or potentially ionic hydrophilizing compound B containing at least one hydroxyl group per molecule; c) a radiation-curable component C containing at least 2 (meth)acrylate groups per molecule; wherein the double bond density of the composition is at least 7 mol / kg, based on its total weight.

2. The aqueous composition according to claim 1, wherein the radiation-curable component C is hydroxyl-functional.

3. The aqueous composition according to claim 2, wherein the OH number of component C is from 1 to 60.

4. The composition according to any one of claims 1 to 3, wherein the acid value of a reaction product of components A and B in the presence of a radiation-curable component C which is free of hydroxyl groups; or b) a reaction product of components A, B and C in the presence of a radiation-curable component C which is hydroxyl-functional is at least 80 mg KOH / g.

5. The composition according to any one of claims 1 to 4, wherein the weight proportion of component C is at least 50%, based on the sum of the weight proportions of components A, B and C.

6. The composition according to any one of claims 1 to 5, wherein the polyisocyanate component A consists to an extent of at least 90% of its total weight of aliphatic and / or cycloaliphatic polyisocyanates.

7. The composition according to any one of claims 1 to 6, wherein the polyisocyanate component A comprises oligomeric polyisocyanates.

8. The composition according to any one of claims 1 to 7, wherein the molar ratio of isocyanate-reactive groups to isocyanate groups in the reaction mixture is from 1 : 1 to 1.2:

1.

9. The composition according to any one of claims 1 to 8, wherein the weight proportion of components A, B and C is at least 90%, based on all ingredients of the dispersion except water.

10. An aqueous coating composition comprising at least one aqueous composition according to any one of claims 1 to 9 as component (i) and at least one polyacrylate dispersion or at least one polyurethane dispersion or a mixture of at least one polyacrylate dispersion and at least one polyurethane dispersion as component (ii).

11. The coating composition according to claim 10, wherein the weight proportion of solids of component (i) is from 5% to 60%, based on the total mass of all solids of components (i) and (ii).

12. A coating obtained or obtainable from the coating composition according to claim 10 or 11.

13. A surface coated with the coating composition according to claim 10 or 11.

14. A coating obtained or obtainable from the aqueous composition according to any one of claims 1 to 9.

15. A surface coated with the coating according to claim 14.

16. The surface according to claim 13 or 15, which is selected from the group consisting of wood, plastic, metal and composite materials. ​ ​ ​ ​ ​ ​ ​ 17. Use of the aqueous composition according to claims 1 to 9 for improving the block resistance and / or the chemical resistance of polyacrylate dispersions and / or polyurethane dispersions.

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