EP3174910A1

EP3174910A1 - Methods for producing and using aqueous polyurethane/polyacrylate hybrid dispersions and use of said aqueous polyurethane/polyacrylate hybrid dispersions in coating agents

Info

Publication number: EP3174910A1
Application number: EP15747133.5A
Authority: EP
Inventors: Ekkehard Jahns; Timo Mangel; Christine Roesch; Paola ROMANATO; Yeni Burk; Joachim Pakusch
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 2014-08-01
Filing date: 2015-07-29
Publication date: 2017-06-07
Also published as: US20170226377A1; AU2015295375A1; CN106795266A; CN106795266B; US10336912B2; MX2017001518A; BR112017001895A2; AR101399A1; WO2016016286A1; JP2017532386A

Abstract

The present invention relates to an aqueous polyurethane (PU)/polyacylate hybrid dispersion that can be obtained by the radical polymerization of at least one acrylate polymer (A1) in the presence of at least one polyurethane (P1), and to a method for producing said aqueous polyurethane/polyacrylate hybrid dispersions, characterized in that (a) an aqueous polyurethane dispersion is produced and (b) the polyurethane dispersion thus produced is used as a raw material for the additional synthesis of a polyacrylate dispersion. The invention also relates to the use of the hybrid dispersion thus obtained as a binder in filled coating agents, in particular as a binder for flexible roof coatings.

Description

Process for the preparation and use of aqueous polyurethane-polyacrylate hybrid dispersions and their use in coating compositions

description

The present invention is an aqueous polyurethane (PU) -polyacrylate hybrid dispersion obtainable by free-radical polymerization of at least one acrylate (A1) in the presence of at least one polyurethane (P1), and a process for preparing these aqueous polyurethane-polyacrylate hybrid dispersions in that (a) an aqueous polyurethane dispersion is prepared and (b) the polyurethane dispersion thus prepared is used as raw material for the additional synthesis of a polyacrylate dispersion and the use of the hybrid dispersion thus obtained as a binder in filled coating compositions, in particular as a binder for flexible Roofing layers.

Aqueous polyurethane dispersions are used as low-solvent or solvent-free coating compositions for wood finishes, as leather finishes and as printing ink binders. These applications are mostly clearcoats or pigmented coatings. The advantage of these coatings based on aqueous polyurethane dispersions is the possibility of controlling the microphase morphology by choosing the relative proportions of hard and soft segments along the polymer chains in the polyurethane. In particular, the mechanical properties are to be emphasized: High abrasion resistance, very good hardness or toughness, good elastic properties, in particular a very good low-temperature elasticity.

Aqueous acrylate polymer dispersions are well known. These are fluid systems which contain a disperse phase in aqueous dispersion medium consisting of a plurality of intertwined polymer chains, which are known as polymer matrices or polymer particles, in disperse distribution. The average diameter of the polymer particles is frequently in the range from 10 to 1000 nm, in particular in the range from 50 to 500 nm. Aqueous polymer dispersions are used as binders in a large number of industrial applications. The polymer dispersions usually consist of styrene acrylates, pure acrylates, vinyl acetates or styrene-butadiene as a raw material class.

Polyurethane dispersions are considerably more expensive to produce than acrylate dispersions. Therefore, attempts have been made again and again to prepare mixtures between polyurethane and acrylate dispersions. This can be done by simple physical mixing of the two dispersion types prepared separately, as described, for example, in WO201 / 00035. The disadvantage, however, is that one usually only gets virtually all the properties in a mixture, and one can not work out particular advantages of one or another technology of the dispersions in the desired manner. The second possibility is a chemical combination of the two dispersions, which can then be suitably chemically coupled to one another by a reaction. In this case, one has significantly more synthetic options to take advantage of one or the other technology in the hybrid of both technologies. Chemically bonded PU-acrylate hybrids can therefore exhibit better properties than can be the case with simple physical blends.

Polyurethane dispersions are used today mostly in unfilled paints, e.g. Leather or wood coatings Usually, clearcoats or only pigmented coatings are used, without or only with a very small proportion of fillers. When trying to use these binders in higher-filled, water-based paints, significant instabilities occur.

The proportion of fillers / pigments can be described by the pigment volume concentration (PVK). The pigment volume concentration represents the volume ratio between pigments / fillers and the binder in the cured paint film. To calculate the pigment volume concentration, the volumes of the individual pigments, fillers and binders are initially calculated from their quantities (masses) and densities (A. Goldschmidt, H.-J. Streitberger, BASF Handbook Coating Technology, 2002, Vincentz Verlag). Then, the obtained volumes of the pigments and fillers contained in the formulation are divided by the volumes of all the solid raw materials.

For the sake of simplicity, the additives which are likewise contained in the formulation are usually not taken into account in the calculation. Solvents and water are no longer present in the dried coating and are not taken into account in the calculation of the PVK.

The PVK is usually expressed in% and is between 0% (clear coat without pigments or fillers) and 100% (only theoretically possible because without binder).

Inventive coating compositions in z. Example, a PVK in the range of 5 to 85, wherein the binders are of course also suitable for clearcoat applications in which no or only very small amounts of pigments and / or fillers are added. For flexible roof coatings, coatings having a PVC of from about 10 to 40 are particularly preferably used.

The customary polyurethane dispersions of the prior art are usually not "compatible with the filler." It is therefore necessary to carry out modifications to the known aqueous polyurethane dispersions in order to make them more compatible with the fillers.Otherwise, the PU-acrylate hybrids produced therefrom are also insufficiently compatible with fillers. a prerequisite for medium to high filling, typical dyeing and coating applications.

US Pat. No. 5,629,402 describes coatings with polyurethane dispersions which are extremely permeable to water vapor, but at the same time have only a slight tendency to swell in Show water. The polyurethane dispersions contain ionic groups and polyethylene glycols as raw materials in the PU main chain and a Vernetzungsagenz. Useful are water vapor permeable coatings for flexible substrates such as textiles, leather, paper and the like. The use of the polyurethane dispersions described there as raw materials, however, gives only PU acrylate hybrids with limited stability to fillers.

A large number of patents also describes polyurethane-polyacrylate hybrid dispersions. Thus, WO 2012/84668 describes polyurethane-polyacrylate hybrid dispersions obtainable by two-stage free-radical polymerization of ethylenically unsaturated compounds in the presence of at least one polyurethane (P1), wherein in a first stage at least one ethylenically unsaturated compound (e) in the presence of at least one Polyurethane (P1), at least one redox initiator system (I) and at least one iron compound (F) at least partially free-radically polymerized and then in a second stage at least one ethylenically unsaturated compound (f) radically polymerized. The hybrid dispersions described therein, however, show only limited stability with respect to fillers.

WO 2013/139019 describes polyurethane-polyacrylate hybrid dispersions obtainable by preparation of a polyurethane dispersion with concomitant use of dimethylolpropionic acid, addition of an acrylate monomer and or styrene, neutralization and subsequent dispersion of the reaction mixture in water and subsequent addition of acrylate monomers and polymerization of the acrylate step Concomitant use of 1 to 3% acid monomers. The disadvantage is the inadequate filler compatibility of these hybrids when used in highly filled inks.

EP 2 666 800 describes polyurethane-polyacrylate hybrid dispersions and their use for hair cosmetics comprising at least one sulfonated polyurethane and at least one acrylate polymer, wherein the acrylate polymer contains at least one carboxyl group-containing monomer and wherein a chain-transferring substance is used for the preparation of the acrylate. The field of application is hair cosmetics. However, the teaching of this application can not be applied to the higher solids contents of polyurethane dispersions necessary for coatings: the described amounts of 23% or 38% polyethylene glycol in Examples 1 to 3 result only at a low solids content of 15% and 19%, respectively. stable dispersions. With the solid contents of the dispersions of> 30% to 50%, which are necessary for flexible roof coatings, stable dispersions are no longer obtained with the teaching of EP 2 666 800.

US Pat. No. 7,358,295 describes polyurethane-polyacrylate hybrid dispersions as coatings for reducing electrostatic charging, which contain 12 to 80% by weight of polyalkylene oxides in side chains in the polyurethane fraction. The acrylate part also contains polyalkylene oxide macromers with a molecular weight of 100-10,000. The described hybrids do not show sufficient filler compatibility when used in highly filled colors. It was therefore the task of developing polyurethane-acrylate hybrid dispersions which are significantly more compatible with the filler than the polyurethane-polyacrylate hybrid dispersions known in the prior art and which, owing to particularly good properties with respect to toughness and elasticity, even at temperatures below that Mark freezing point. These PU-acrylate hybrid dispersions, especially when used as a binder for filled elastic paints and coatings such as pasty tile adhesives, moisture proofing, flooring adhesives, primers, cementitious sealing slurries, sealants, assembly adhesives or for horizontal roof surfaces should show advantages over conventional acrylate dispersions, without the high cost of have pure polyurethane dispersions.

The object has surprisingly been achieved by an aqueous polyurethane-polyacrylate hybrid dispersion obtainable by free-radical polymerization of an acrylate polymer (A1) in the presence of at least one polyurethane (P1), at least one initiator system, wherein the at least one polyurethane (P1) has a content of polyalkylene oxide of at least 10 g / kg of polyurethane and a content of a sulfonated raw material of at least 25 mmol per kg of polyurethane, the acrylate polymer has a glass transition temperature of -50 ° C to 50 ° C, and the mass fraction of the polyurethane at least 5% and at most 95% with respect on the entire hybrid polymer. Another object of the invention is a process for the preparation of the polyurethane-polyacrylate hybrid dispersion according to the invention, characterized in that

(a) the polyurethane (P1) is first prepared, and

(B) the polyurethane (P1) is used as a seed for the preparation of the acrylate polymer (A1).

Another object of the present invention is the use of the polyurethane-polyacrylate hybrid dispersion according to the invention as a binder for elastic paints, pasty tile adhesives, moisture proofing, flooring adhesives, primers, cementitious sealing slurries, sealants, assembly adhesives or flexible Dachbeschich- tions, and coating compositions containing the polyurethane of the invention - Polyacrylate hybrid dispersions.

Especially preferred is the use of the polyurethane-polyacrylate hybrid dispersion according to the invention as a binder for elastic paints and for flexible roof coatings.

The acrylate dispersion (A1) is polymerized as described below, preferably in a semi-batch process. Particularly preferred polyurethane-polyacrylate hybrid dispersions contain long-chain alkanol-initiated polyethylene oxides and sodium salts of 2-aminoethyl-2-aminoethanesulfonic acid, which are especially compatible with fillers.

To prepare the PU-acrylate hybrids according to the invention, first of all a polyurethane dispersion is used which is compatible with the filler. It may be necessary that this PU dispersion is equipped with more functional groups for the purpose of good filler compatibility than is necessary or even useful for a PU dispersion alone. Although this larger amount of hydrophilic groups in the PU dispersion contributes to a greater water absorption of films of pure PU dispersion, but a PU-acrylate hybrid of such a particularly well-stabilized PU dispersion then does not necessarily show too large Water absorption of a filled paint. On the contrary, PU-acrylate hybrid dispersions prepared by these synthesis steps were obtained, which exhibited even lower water intakes or water sensitivities of the filled inks produced therefrom than was to be expected.

The polyurethanes (P1) according to the invention can be prepared by the following process, as described in DE 10161 156, the disclosure content of which is incorporated herein by reference in its entirety:

Aqueous dispersions containing a polyurethane, composed of

a) diisocyanates,

b) Diols, of which

b1) 10 to 100 mol%, based on the total amount of diols (b), have a molecular weight of 500 to 5000, and

b2) 0 to 90 mol%, based on the total amount of diols (b), have a molecular weight of 60 to 500 g / mol,

c) monomers other than monomers (a) and (b) having at least one isocyanate group or at least one isocyanate-reactive one

Group, further carrying at least one hydrophilic group or a potentially hydrophilic group, whereby the water dispersibility of the polyurethanes

is effected

d) optionally other polyfunctional compounds other than the monomers (a) to (c), having reactive groups which are alcoholic hydroxyl groups, primary or secondary amino groups or isocyanate groups, and

e) optionally monovalent compounds other than the monomers (a) to (d), having a reactive group which is an alcoholic hydroxyl group, a primary or secondary amino group or an isocyanate group,

obtainable by reacting the monomers a), b), c) and optionally d), and e) in the presence of a catalyst, for example a tin salt, such as dibutyltin dilaurate (DE-A 199 59 6539) or tin-free catalysts, for example based on bismuth neodecanoate (eg Borchikat ^® 315 of the company. OMG Borchers GmbH, Langenfeld, Germany). The aqueous dispersions according to the invention comprise polyurethanes which, in addition to other monomers, are derived from diisocyanates a), preference being given to using those diisocyanates a) which are customarily used in polyurethane chemistry. To be mentioned in particular as monomers (a) diisocyanates X (NCO) 2, wherein X is an aliphatic hydrocarbon radical having 4 to 12 carbon atoms, a

cycloaliphatic or aromatic hydrocarbon radical having 6 to 15 carbon atoms or an araliphatic hydrocarbon radical having 7 to 15 carbon atoms. Examples of such diisocyanates are tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), dodecamethylene diisocyanate, 1,4-diisocyanatocyclohexane, 1-isocyanato-3,5,5-trimethyl-5-isocyanatomethylcyclohexane (IPDI), 2,2-bis (4-isocyanatocyclohexyl ) -propane, trimethylhexane diisocyanate, 1,4-diisocyanatobenzene, 2,4-diisocyanatotoluene, 2,6-diisocyanatotoluene, 4,4'-diisocyanatodiphenylmethane, 2,4'-diisocyanato-diphenylmethane, p-xylylene diisocyanate, Tetramethylxylylene diisocyanate (TMXDI), the isomers of bis (4-isocyanato- cyclohexyl) methane (HMDI) such as the trans / trans, the cis / cis and the cis / trans isomers and mixtures consisting of these compounds.

Such diisocyanates are available commercially. As mixtures of these isocyanates are especially the mixtures of the respective structural isomers of diisocyanatotoluene

and diisocyanato-diphenylmethane of importance, in particular, the mixture of 80 mol% of 2,4-diisocyanatotoluene and 20 mol% of 2,6-diisocyanatotoluene is suitable.

Furthermore, the mixtures of aromatic isocyanates such as 2,4-diisocyanatotoluene and / or 2,6-diisocyanatotoluene with aliphatic or cycloaliphatic isocyanates such as hexamethylene diisocyanate or IPDI are particularly advantageous, the preferred mixing ratio of aliphatic to aromatic isocyanates 4: 1 to 1: 4. For the construction of the polyurethanes can be used as compounds except the aforementioned also isocyanates, which in addition to the free isocyanate groups further blocked isocyanate groups, eg. B. wear uretdione groups. With regard to good film formation and elasticity, suitable diols (b) are primarily relatively high molecular weight diols (b1) which have a molecular weight of about 500 to 5000, preferably about 1000 to 3000 g / mol. The diols (b1) are in particular polyester polyols, the z. B. from Ullmann's Encyclopedia of Industrial Chemistry, 4th Edition, Volume 19, pp 62 to 65 are known. Preference is given to using polyesterpolyols which are obtained by reacting dihydric alcohols with dibasic carboxylic acids. Instead of the free polycarboxylic acids, it is also possible to use the corresponding polycarboxylic acid anhydrides or corresponding polycarboxylic acid esters of lower alcohols or mixtures thereof to prepare the polyesterpolyols.

As sulfonated polyester polyols it is also possible to use compounds as described, for example, in US Pat. from EP 2 666 800, e.g. the product "SS55-225-130", sulfonated polyester-diol with free sodium sulfonate groups, molecular weight 550, Crompton Corp., Middlebury, CT.

The polycarboxylic acids may be aliphatic, cycloaliphatic, araliphatic, aromatic or heterocyclic and optionally, for. B. by halogen atoms, substituted and / or be unsaturated. Examples of these are: suberic acid, azelaic acid, phthalic acid, isophthalic acid, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, tetrachlorophthalic anhydride, endomethylenetetrahydrophthalic anhydride, glutaric anhydride, maleic acid, maleic anhydride, fumaric acid, dimer fatty acids and dimethylsulfoisophthalic acid. Preferred are dicarboxylic acids of the general formula HOOC- (CH 2) y COOH, where y is a number from 1 to 20, preferably an even number from 2 to 20, z. Succinic acid, adipic acid, sebacic acid and dodecanedicarboxylic acid. As polyhydric alcohols come z. As ethylene glycol, propane-1, 2-diol, propane-1, 3-diol, butane-1, 3-diol, butene-1, 4-diol, butyne-1, 4-diol, pentane-1, 5 diol, neopentyl glycol, bis (hydroxymethyl) cyclohexanes such as 1,4-bis (hydroxymethyl) cyclohexane, 2-methyl-propane-1,3-diol, methylpene-tandiols, furthermore diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, dipropylene glycol, Polypropylene glycol, dibutylene glycol and polybutylene glycols into consideration. Alcohols of the general formula HO- (CH 2) x -OH are preferred, where x is a number from 1 to 20, preferably an even number from 2 to 20. Examples of these are ethylene glycol, butane-1, 4-diol, hexane-1, 6-diol, octane-1, 8-diol and dodecane-1, 12-diol. Further preferred is neopentyl glycol.

Furthermore, polycarbonate diols, as they come z. B. by reacting phosgene with an excess of the mentioned as synthesis components for the polyester polyols low molecular weight alcohols can be obtained, into consideration. Also suitable are lactone-based polyesterdiols, which are homopolymers or copolymers of lactones, preferably addition products of lactones which are terminated by hydroxyl groups, to suitable difunctional starter molecules. Preferred lactones are those which are derived from compounds of the general formula HO- (CH 2) z -COOH, where z is a number from 1 to 20 and an H atom of a methylene unit is also a C 1 - to C 4 -alkyl radical may be substituted. Examples are C-caprolactone, β-propiolactone, γ-butyrolactone and / or methyl-e-caprolactone and mixtures thereof. Suitable starter components are for. As the above-mentioned as a structural component for the polyester polyols low molecular weight dihydric alcohols. The corresponding polymers of ε-caprolactone are particularly preferred. Lower polyester diols or polyether diols may also be used as starters for the preparation of the lactone polymers. Instead of the polymers of lactones, it is also possible to use the corresponding, chemically equivalent polycondensates of the hydroxycarboxylic acids corresponding to the lactones.

In addition, suitable monomers (b1) are polyether diols. They are in particular by polymerization of ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran, styrene oxide or epichlorohydrin with itself, z. B. in the presence of BF3 or by addition of these compounds, optionally in admixture or in succession, to starting components with reactive hydrogen atoms, such as alcohols or amines, for. For example, water, ethylene glycol, propane-1, 2-diol, propane-1, 3-diol, l, 2-bis (4-hydroxydiphenyl) propane or aniline available. Particularly preferred is polytetrahydrofuran having a molecular weight of 240 to 5000, and especially 500 to 4500. In addition, mixtures of polyester diols and Polyether diols can be used as monomers (b1). Also suitable are polyhydroxy-olefins, preferably those having 2 terminal hydroxyl groups, for. B. α, ω-dihydroxypolybutadiene, α, ω-Dihydroxypolymethacrylester or α, ω-Dihydroxypolyacrylester as monomers (c1). Such compounds are known, for example, from EP-A 622 378. Further suitable polyols are polyacetals, polysiloxanes and alkyd resins.

The polyols can also be used as mixtures in the ratio of 0.1: 1 to 1: 9. The hardness and modulus of elasticity of the polyurethanes can be increased if, as diols (b), low molecular weight diols (b2) having a molecular weight of from about 60 to 500, preferably from 62 to 200, g / mol are used in addition to the diols (b1).

The monomers (b2) used are in particular the synthesis components of the short-chain alkanediols mentioned for the preparation of polyester polyols, where diols having 2 to 12 C atoms, unbranched diols having 2 to 12 C atoms and an even number of C atoms and pentane 1, 5-diol and neopentyl glycol are preferred.

Preferably, the proportion of the diols (b1), based on the total amount of the diols (b) is 10 to 100 mol% and the proportion of the monomers (b2), based on the total amount of the diols (b) 0 to 90 mol%. The ratio of the diols (b1) to the monomers (b2) is particularly preferably 0.1: 1 to 5: 1, more preferably 0.2: 1 to 2: 1.

In order to achieve the water-dispersibility of the polyurethanes, the polyurethanes, in addition to the components (a), (b) and, if appropriate, (d) are monomers (c) which are different from components (a), (b) and (d) and which are at least one Isocyanate group or at least one isocyanate-reactive group and moreover at least one hydrophilic group or a group which can be converted into a hydrophilic group bear.

In the following text, the term "hydrophilic groups or potentially hydrophilic groups" is abbreviated to "(potentially) hydrophilic groups". The (potentially) hydrophilic groups react much more slowly with isocyanates than the functional groups of the monomers which serve to build up the polymer main chain.

The proportion of components having (potentially) hydrophilic groups in the total amount of components (a), (b), (c), (d) and (e) is generally such that the molar amount of (potentially) hydrophilic groups, based on the amount by weight of all monomers (a) to (e), 30 to 1000, preferably 50 to 500 and particularly preferably 80 to 300 mmol / kg.

The (potentially) hydrophilic groups may be nonionic or, preferably, (potentially) ionic hydrophilic groups. Suitable nonionic hydrophilic groups are, in particular, polyethylene glycol ethers of preferably 5 to 150, preferably 40 to 120, ethylene oxide repeat units. The content of polyethylene oxide units is generally 0.1 to 15, preferably 1 to 10 wt .-%, based on the amount by weight of all monomers (a) to (e). Preferred monomers having nonionic hydrophilic groups are polyethylene oxide diols, polyethylene oxide monools and the reaction products of a polyethylene glycol and a diisocyanate which carry a terminally etherified polyethylene glycol radical. Such diisocyanates and processes for their preparation are given in US Pat. Nos. 3, 905, 929 and US Pat. No. 3,920,598.

Ionic hydrophilic groups are especially anionic groups such as the sulfonate, the carboxylate and the phosphate group in the form of their alkali metal or ammonium salts, and also cationic groups such as ammonium groups, in particular protonated tertiary amino groups or quaternary ammonium groups.

Potentially ionic hydrophilic groups are, in particular, those which can be converted into the abovementioned ionic hydrophilic groups by simple neutralization, hydrolysis or quaternization reactions. As carboxylic acid groups or tertiary amino groups.

(Potentially) ionic monomers (c) are e.g. As in Ullmann's Encyclopedia of Industrial Chemistry, 4th Edition, Volume 19, pp 31 1 -313 and described for example in DE-A 14 95 745 in detail.

As (potentially) cationic monomers (c) are especially monomers having tertiary amino groups of particular practical importance, for example: tris (hydroxyalkyl) -amine, Ν, Ν'-bis (hydroxyalkyl) -alkylamine, N-hydroxyalkyl-dialkylamines , Tris (aminoalkyl) -amines, Ν, Ν'-bis (aminoalkyl) -alkylamines, N-aminoalkyl-dialkylamines, wherein the alkyl radicals and alkanediyl moieties of these tertiary amines independently of one another consist of 1 to 6 carbon atoms. Furthermore, tertiary nitrogen atoms having polyethers having preferably two terminal hydroxyl groups, as z. Example, by alkoxylation of two bound to amine nitrogen hydrogen atoms containing amines, eg. As methylamine, aniline or Ν, Ν'-dimethylhydrazine, are accessible in per se conventional manner, into consideration. Such polyethers generally have a molecular weight between 500 and 6000 g / mol.

These tertiary amines are prepared either with acids, preferably strong mineral acids such as phosphoric acid, sulfuric acid, hydrohalic acids or strong organic acids, or by reaction with suitable quaternizing agents such as C 1 - to C 6 -alkyl halides or benzyl halides, e.g. As bromides or chlorides, transferred to the ammonium salts.

Suitable monomers with (potentially) anionic groups are usually aliphatic, cycloaliphatic, araliphatic or aromatic carboxylic acids and sulfonic acids which carry at least one alcoholic hydroxyl group or at least one primary or secondary amino group. Preference is given to dihydroxyalkylcarboxylic acids, especially with 3 to 10 carbon atoms, as also described in US Pat. No. 3,412,054. In particular, compounds of the general formula (c1)

I

BO-R ¹ -CR ² OH (Ci)

COOH in which R ¹ and R ^{2 is} a C 1 - to C 4 -alkanediyl unit and R ^{3 is} a C 1 - to C 4 -alkyl unit and especially dimethylolpropionic acid (DMPA) is preferred. Also suitable are corresponding dihydroxysulfonic acids and dihydroxyphosphonic acids, such as 2,3-dihydroxypropanephosphonic acid.

Otherwise suitable are dihydroxyl compounds having a molecular weight above 500 to 10,000 g / mol with at least 2 carboxylate groups, which are known from DE-A 39 11 827. They are obtainable by reacting dihydroxyl compounds with tetracarboxylic dianhydrides such as pyromellitic dianhydride or cyclopentanetetracarboxylic dianhydride in a molar ratio of 2: 1 to 1:05 in a polyaddition reaction. Particularly suitable dihydroxyl compounds are the monomers (b2) listed as chain extenders and the diols (b1).

Suitable monomers (c) with isocyanate-reactive amino groups are aminocarboxylic acids such as lysine, β-alanine or the adducts of aliphatic diprimary diamines mentioned in DE-A 20 34 479 to α, β-unsaturated carboxylic or sulfonic acids.

Such compounds obey, for example

the formula (c2)

H ₂ NR ⁴ -NH-R ⁵ -X (c ₂ ) in which R ⁴ and R ⁵ independently of one another are a C 1 - to C 6 -alkanediyl unit, preferably ethylene and X is -COOH or -SO ₃ H

Particularly preferred compounds of the formula (c2) are the N- (2-aminoethyl) -2-amino-ethane carboxylic acid and the N- (2-aminoethyl) -2-aminoethanesulfonic acid or the corresponding alkali metal salts, with sodium as the counterion being particularly preferred. Further preferred are the adducts of the above-mentioned aliphatic diprimary diamines with 2-acrylamido-2-methylpropanesulfonic acid, as described, for. B. in DE Patent 19 54 090 are described. Further suitable aminosulfonic acids are, for example, sodium 2 - ((2-aminoethyl) amino) -ethanesulfonate, diaminoalkylsulfonic acid and its salts, for example ethylene diisocyanate. Mino-.beta.-ethylsulfonic acid, ethylenediaminopropyl- or -butylsulfonic acid, 1, 2- or 1, 3-propylenediamino-.beta.-ethylsulfonic acid.

If monomers having potentially ionic groups are used, their transfer to the ionic form can take place before, during, but preferably after the isocyanate polyaddition, since the ionic monomers are often difficult to dissolve in the reaction mixture. The sulfonate or carboxylate groups are particularly preferably in the form of their salts with an alkali ion or an ammonium ion as the counterion. The monomers (d), which are different from the monomers (a) to (c) and which are optionally also constituents of the polyurethane, generally serve

Crosslinking or chain extension. They are generally more than divalent non-phenolic alcohols, amines having 2 or more primary and / or secondary amino groups, and compounds which carry one or more primary and / or secondary amino groups in addition to one or more alcoholic hydroxyl groups.

Alcohols with a value higher than 2, which can serve to set a certain degree of branching or crosslinking, are for. B. trimethylolpropane, glycerol or sugar. Also suitable are monoalcohols which, in addition to the hydroxyl group, carry a further isocyanate-reactive group, such as monoalcohols having one or more primary and / or secondary amino groups, eg. B. monoethanolamine. Polyamines having 2 or more primary and / or secondary amino groups are used especially when the chain extension or crosslinking is to take place in the presence of water, since amines usually react faster than alcohols or water with isocyanates.

This is often required when aqueous dispersions of high molecular weight crosslinked polyurethanes or polyurethanes are desired. In such cases, the procedure is to prepare prepolymers with isocyanate groups, to disperse them rapidly in water, and then to chain extend or crosslink them by adding compounds containing several isocyanate-reactive amino groups.

Amines suitable for this purpose are generally polyfunctional amines of the molecular weight range from 32 to 500 g / mol, preferably from 60 to 300 g / mol, which contain at least two amino groups selected from the group of primary and secondary amino groups. Examples of these are diamines such as diaminoethane, diaminopropanes, diaminobutanes, diaminohexanes, piperazine, 2,5-dimethylpiperazine, amino-3-aminomethyl-3,5,5-trimethylcyclohexane (isophoronediamine, IPDA), 4,4'-diaminodicyclohexylmethane , 1, 4-diamino cyclohexane, aminoethyl ethanolamine, hydrazine, hydrazine hydrate or triamines such as diethylene triamine or 1, 8-diamino-4-aminomethyloctan. The amines may also be in blocked form, for. In the form of the corresponding ketimines (see, for example, CA-A 1 129 128), ketazines (cf., for example, US Pat. No. 4,269,748) or amine salts (see US Pat. No. 4,292,226). Oxazolidines, as used for example in US Pat. No. 4,192,937, also represent blocked polyamines which are suitable for the preparation of the polyurethanes according to the invention for chain extension of Prepolymer can be used. When such capped polyamines are used, they are generally mixed with the prepolymers in the absence of water, and this mixture is then mixed with the dispersion water or part of the dispersion water, so that the corresponding polyamines are hydrolytically released. Preference is given to using mixtures of di- and triamines, particularly preferably mixtures of isophoronediamine (IPDA) and diethylenetriamine (DETA).

The polyurethanes preferably contain from 1 to 30, particularly preferably from 4 to 25, mol%, based on the total amount of components (b) and (d), of a polyamine

at least 2 isocyanate-reactive amino groups as monomers (d). Alcohols with a value higher than 2, which can serve to set a certain degree of branching or crosslinking, z. B. trimethylolpropane, glycerol or sugar. For the same purpose higher than divalent isocyanates can also be used as monomers (d). Commercially available compounds are, for example, the isocyanurate or the biuret of hexamethylene diisocyanate.

Monomers (e), which are optionally used, are monoisocyanates, monoalcohols and monoprimary and secondary amines. In general, their proportion is at most 10 mol%, based on the total molar amount of the monomers. These monofunctional compounds usually carry further functional groups, such as olefinic groups or carbonyl groups, and serve to introduce functional groups into the polyurethane which can be used for dispersing or crosslinking or for further polymer-analogous reaction of the

Polyurethane allow. Suitable monomers are, for example, isopropenyl-α, α-dimethylbenzyl isocyanate (TMI) and esters of acrylic or methacrylic acid, such as hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate or hydroxypropyl methacrylate. Coatings with a particularly good property profile are obtained especially when, as monomers (a), essentially only aliphatic diisocyanates, cycloaliphatic diisocyanates or TMXDI and as monomer (b1) essentially only polyesterdiols synthesized from said aliphatic diols and diacids are used , This monomer combination is excellently supplemented as component (c) by diamino acid salts; more particularly by the N- (2-aminoethyl) -2-aminoethanesulfonic acid, the N- (2-aminoethyl) -2-aminoethanecarboxylic acid or its corresponding alkali metal salts, the Na salts being most suitable, and a mixture of DETA IPDA as component (d). In the field of polyurethane chemistry, it is well known how the molecular weight of the polyurethanes can be adjusted by selecting the proportions of the monomers reactive with one another and the arithmetic mean of the number of reactive functional groups per molecule.

Normally, the components (a) to (e) and their respective molar amounts are chosen such that the ratio A: B with A) the molar amount of isocyanate groups and B) the sum of the molar amount of the hydroxyl groups and the molar amount of the functional groups with Isocyanates can react in an addition reaction 0.5: 1 to 2: 1, before- zugt 0.8: 1 to 1, 5, more preferably 0.9: 1 to 1, 2: 1 amounts. Most preferably, the ratio A: B is as close as possible to 1: 1.

The monomers (a) to (e) used carry on average usually 1.5 to 2.5, preferably 1.9 to 2.1, particularly preferably 2.0 isocyanate groups or functional groups which can react with isocyanates in an addition reaction , The polyaddition of components (a) to (e) for the preparation of the polyurethane present in the aqueous dispersions of the invention can be carried out at reaction temperatures of 20 to 180 ° C, preferably 70 to 150 ° C under atmospheric pressure or under autogenous pressure.

The required reaction times are usually in the range of 1 to 20 hours, in particular in the range of 1, 5 to 10 hours. It is known in the field of polyurethane chemistry how the reaction time is affected by a variety of parameters such as temperature, concentration of monomers, reactivity of the monomers. The polyaddition of the monomers a), b), c) and optionally d) and e) for the preparation of the PU dispersion according to the invention is carried out in the presence of a catalyst.

It is known in the field of polyurethane chemistry, as the reaction time

is influenced by a variety of parameters such as temperature, concentration of monomers, reactivity of the monomers.

To accelerate the reaction of the diisocyanates, the usual catalysts can be used. In principle, all catalysts commonly used in polyurethane chemistry come into consideration. These are, for example, organic amines, in particular tertiary aliphatic, cycloaliphatic or aromatic amines, and / or Lewis acid organic metal compounds. As the Lewis acidic organic metal compounds, e.g. Tin compounds, such as stannous (1: 1) salts of organic carboxylic acids, e.g. Tin (II) acetate, stannous octoate, stannous ethylhexoate and stannous laurate and the dialkyltinous (IV) salts of organic carboxylic acids, eg dimethyltin diacetate, dibutyltin diacetate, dibutyltin dibutyrate, Dibutyltin bis (2-ethylhexanoate), di-butyltin dilaurate, dibutyltin maleate, dioctyltin dilaurate and dioctyltin diacetate. Metal complexes such as acetylacetonates of iron, titanium, aluminum, zirconium, manganese, nickel and cobalt are also possible. Other metal catalysts are described by Blank et al. in Progress in Organic Coatings, 1999, Vol. 35, pages 19-29.

Preferred Lewis acidic organic metal compounds are dimethyltin diacetate,

Dibutyltin dibutyrate, dibutyltin bis (2-ethylhexanoate), dibutyltin dilaurate, diocytic tin dilaurate, zirconium acetylacetonate and zirconium 2,2,6,6-tetramethyl-3,5-heptanedionate.

Also bismuth and cobalt catalysts and cesium salts can be used as catalysts. Suitable cesium salts are those compounds in which the following anions are used: F, Cl, CIO, CIO 3, CIO 4, Br, J, JO 3, CN, OCN, NO 2, NO 3 -, HC03-, C03 ^{2 "} , S2-, SH-, HSO3-, SO3 ^2" , HS04-, SO4 ^{2 "} , S202 ^2" , S204 ² -, S20s2-, S205 ^{2 "} , S2012 ^" , S20a2-, H2P02, H2P04, HP04 ^{2 "} , P04 ^3" , P2014-, (OCnH2n + 1) -, (CnH2n-102) -, (CnH2n-302) - as well as (Cn + 1 H2n-204) 2-, where n is the numbers 1 to 20.

Cesium carboxylates in which the anion is the formula are preferred

(CnH2n-102) - as well as (Cn + 1 H2n-204) 2- with n equal to 1 to 20, obeys. Particularly preferred cesium salts have as anions monocarboxylates of the general formula

(CnH2n-102) -, where n is the numbers 1 to 20. Particular mention should be made here of formate, acetate, propionate, hexanoate and 2-ethylhexanoate. Rührkessel come into consideration as polymerization, in particular when by the concomitant use of solvents for a low viscosity and a

good heat dissipation is taken care of.

If the reaction is carried out in bulk, are suitable due to the usually high

Viscosities and usually only short reaction times especially extruder, especially self-cleaning multi-screw extruder.

In the so-called "prepolymer mixing process", first a prepolymer is prepared which carries isocyanate groups. The components (a) to (d) are hereby

chosen so that the ratio A: B is greater than 1, 0 to 3, preferably 1, 05 to 1, 5 is. The prepolymer is first dispersed in water and simultaneously and / or chain-extended by reaction of the isocyanate groups with amines carrying more than 2 isocyanate-reactive amino groups, or with amines carrying the 2 isocyanate-reactive amino groups, chain extended. Chain extension also occurs when no amine is added. In this case, isocyanate groups are hydrolyzed to amine groups, which react with remaining isocyanate groups of the prepolymers with chain extension.

The average particle size (z average), measured by dynamic light scattering with the Malvern® Autosizer 2 C, the polyurethane dispersions thus prepared is not essential to the invention and is generally <1000 nm, preferably <500 nm, 40 particularly preferably <200 nm and very particularly preferably between 20 and below 200 nm.

The polyurethane dispersions generally have a solids content of 10 to 75, preferably from 20 to 65 wt .-% and a viscosity of 10 to 500 mPas (ICI

Cone / plate viscometer with measuring head C based on ASTM D4287), measured at a temperature of 20 ° C and a shear rate of 250 s-1).

Preferred solvents are immiscible with water indefinitely, have a boiling point at atmospheric pressure of 40 to 100 ° C and do not react or only slowly with the monomers. In most cases, the dispersions are prepared by one of the following processes: According to the "acetone process", an ionic polyurethane is prepared from components (a) to (c) in water-miscible solvent boiling below 100 ° C. under normal pressure. Add so much water until a dispersion forms, in which water is the coherent phase. The "prepolymer mixing process" differs from the acetone process in that not a fully reacted (potentially) ionic polyurethane, but first a prepolymer is prepared which carries isocyanate groups. The components are chosen so that the ratio A: B is greater than 1, 0 to 3, preferably 1, 05 to 1, 5. The prepolymer is first dispersed in water and subsequently chain-extended, if appropriate, by reaction of the isocyanate groups with amines which carry more than 2 isocyanate-reactive amino groups or chain-extended with amines carrying 2 isocyanate-reactive amino groups. Chain extension also occurs when no amine is added. In this case, isocyanate groups are hydrolyzed to amino groups which react with remaining isocyanate groups of the prepolymers with chain extension. Usually, if a solvent was used in the preparation of the polyurethane, most of the solvent is removed from the dispersion, for example by distillation at reduced pressure. Preferably, the dispersions have a solvent content of less than 10 wt .-% and are particularly preferably free of solvents. The dispersions generally have a solids content of from 10 to 75, preferably from 20 to

65 wt .-% and a viscosity of 10 to 500 mPas (measured at a temperature of 20 ° C and a shear rate of 250 s-1).

Aqueous acrylate dispersions have become standard binders for facade paints and roof coatings, for example as repair paints. They provide stable, durable, water- and weatherproof, decorative coatings, mostly on inorganic building materials, but also on wood, old coatings and substrates or metal surfaces. For the protection of flat roofs prefabricated materials are used as rolled goods, eg bituminized fiber or nonwovens or elastomeric materials such as EPDM rubber or thermoplastic elastomers in the initial and repair. Another possibility is the use of two-component, liquid plastic preparations, such as epoxy resins or polyurethanes, which can be rolled up or sprayed on. These materials are characterized by a high elasticity and a high resistance to aging. For the coating of horizontal roof surfaces also dispersion-bound colors can be used, similar to the colors of exterior paints. However, these colors should also be particularly elastic so that they can not fail prematurely in the event of damage to the ground (cracks, etc.), and rainwater can penetrate into the building. In addition, these colors must be weatherproof and UV-resistant in a special way. On dispersion-bound colors for the horizontal roofing so increased demands are made, which may differ from the usual dispersion binders. Dispersion binders for horizontal roof coating are usually not described separately, so that it must be resorted to consideration of the prior art on facade color binding agent.

Water-based polymer dispersions as binders for facade paints and plasters are usually produced from one main monomer each having a high glass transition temperature (hard monomer) and a main monomer having a low glass transition temperature (soft monomer). As hard monomers usually styrene or methyl methacrylate are selected, as the soft monomer most n-butyl acrylate or 2-ethylhexyl acrylate are chosen. The facade color binders are therefore referred to as styrene acrylates or when using methyl methacrylate as a hard monomer as pure acrylates. Most binders for filled paints consist of styrene / n-butyl acrylate or of methyl methacrylate n-butyl acrylate for reasons of good weathering stability in the case of outdoor weathering. The respective amounts of hard and soft monomer are selected depending on the application at the glass transition temperature, which is necessary for the respective use. Binders for solvent-free facade paints usually have a glass transition temperature in the range of 0-5 ° C, low-solvent facade paints in the range of 5-20 ° C and solvent-based facade paints in the range of 20-40 ° C.

Such binders of the prior art are described in EP 771 328, for example, in Examples A, J and K.

WO2013 / 073145 describes aqueous polymer dispersions which comprise (a) at least two monomers M1 having a glass transition temperature> 25 ° C., (b) at least two monomers M2 having a glass transition temperature <25 ° C. and further monomers M3, as binders in coating compositions with particularly good color retention (Color Retention). However, the specification does not specify the elasticity of the colors according to the invention.

DE 10 161 156 describes a water-based polyurethane dispersion, as also known as 1. Stage can be used for a PU-acrylate hybrid dispersion.

By specific variation of the type and amount of the monomers, it is possible for the person skilled in the art to prepare aqueous polymer compositions whose polymers have a glass transition temperature in the desired range. Orientation is possible using the Fox equation. According to Fox (TG Fox, Bull. Am. Phys Soc. 1956 [Ser II] 1, page 123 and Ullmann's Encyclopedia of Industrial Chemistry, Vol. 19, page 18, 4th edition, Verlag Chemie, Weinheim, 1980) applies to a calculation of the glass transition temperature of copolymers to a good approximation: 1 / Tg = X / Tg ¹ + X ² / Tg ² + .... x "/ V, where x ¹ , x ² , .... x ⁿ the Mass fractions of the monomers 1, 2,..., And T _g ¹ , T _g ² ,... T _g ^{n are} the glass transition temperatures of the monomers formed in each case from only one of the monomers 1, 2,. th polymers in degrees Kelvin. The T _g values for the homopolymers of most monomers are known and are listed, for example, in Ullmann's Ecyclopedia of Industrial Chemistry, Vol. 5, Vol. A21, page 169, VCH Weinheim, 1992; Further sources of glass transition temperatures of homopolymers are, for example, J. Brandrup, EH Immergut, Polymer Handbook, 1 ^st Ed., J. Wiley, New York 1966, 2 ^nd Ed. J. Wiley, New York 1975, and 3 ^rd Ed. J. Wiley, New York 1989. For ethyl acrylate, a value of -13 ° C is used.

The actual glass transition temperature can be determined by differential scanning calorimetry (ASTM D 3418-08, so-called "midpoint temperature").

For facade paints and for roof coatings, preference is given to using pure acrylate dispersions with methyl methacrylate and n-butyl acrylate as main monomers, because they have a particularly good UV and weather resistance. However, according to experience, it is not possible with these monomers alone to produce particularly elastic coating compositions. This is indeed possible with the additional use of acrylonitrile, but unwanted yellowing often occurs when weathering paints with these binders.

Facade paints and roof coatings based on disperse binders with the major monomers styrene and n-butyl acrylate are less UV and weather resistant, but when using highly filled inks, i. low binder colors, still good enough. However, it is not known that it is possible on the basis of this monomer combination to produce coating compositions with a particularly high breaking strength and elongation at break.

By the inventive polyurethane-polyacrylate hybrid dispersions obtainable by free-radical polymerization of at least one acrylate polymer A1 in the presence of at least one polyurethane (P1), at least one initiator system, wherein the at least one polyurethane (P1) has a content of polyalkylene oxide of at least 10 g / kg of polyurethane and having a sulfonated raw material content of at least 25 mmol per kg of polyurethane, the acrylate polymer has a glass transition temperature of -50 ° C to 50 ° C, the weight percentage of the polyurethane is at least 5% and at most 99.99% with respect to the entire hybrid polymer , It is possible to produce coating compositions with high tensile strength and elongation at break.

For high elasticity, ie for high breaking strength / elongation at break, the composition of the acrylate dispersion A1 comprises main monomer combinations such as styrene / n-butyl acrylate or methyl methacrylate n-butyl arylate or preferably (a) at least two monomers M1 having a glass transition temperature > 25 ° C, as well

(B) at least two monomers M2 with a glass transition temperature <25 ° C.

and, if appropriate, further monomers M3, which exhibit significantly better breaking strength and tear elongation in the coating compositions according to the invention, in particular in facade paints and roof coatings, than comparable binders from the prior art. The monomer combinations cyclohexyl methacrylate / n-butyl acrylate and the 3-membered combinations styrene / methyl methacrylate n-butyl acrylate, styrene / methyl methacrylate 2-ethylhexyl acrylate, styrene / cyclohexyl methacrylate n-butyl acrylate, styrene / cyclohexyl methacrylate 2-ethylhexyl acrylate, methyl methacrylate n Butyl acrylate 2-ethylhexyl acrylate, cyclohexyl methacrylate, methyl methacrylate, n-butyl acrylate, cyclohexyl methacrylate, methyl methacrylate 2-ethylhexyl acrylate and cyclohexyl methacrylate / n-butyl acrylate 2-ethylhexyl acrylate.

In addition, the UV and weathering stability is very good and the methyl methacrylate / n-butyl acrylate binders despite the additional use actually comparable as unstable known monomers. However, there are no significant deficits in the use of styrene in acrylates in weathering tests for bright or white, filled facade paints and plasters. For the polymerization of the acrylate polymers A1, the following monomers can be used according to the invention:

Examples of the monomers M1 having a glass transition temperature> 25 ° C. are vinyl aromatic compounds, such as vinyltoluene, alpha- and para-methyl-styrene, alpha-butylstyrene, 4-n-butylstyrene and, preferably, styrene, C 1 - to C 4 -alkyl methacrylates by name MMA, ethyl methacrylate, n-propyl methacrylate, i-propyl methacrylate, n-butyl methacrylate, t-butyl acrylate, i-butyl methacrylate, t-butyl methacrylate, t-butyl acrylate, cyclohexyl methacrylate, stearyl acrylate, vinyl acetate, and / or ethylenically unsaturated nitriles. Examples of nitriles are acrylonitrile and methacrylonitrile. Vinyl halides are chloro, fluoro or bromo substituted ethylenically unsaturated compounds, preferably vinyl chloride and vinylidene chloride.

Suitable monomers M2 having a glass transition temperature <25 ° C. are, for example, C 1 - to C 20 -alkyl acrylates, such as methyl acrylate, ethyl acrylate, n- and i-propyl acrylate, n-, i- and sec-butyl acrylate, n- and i-pentyl acrylate, n Hexyl acrylate, 2-ethylhexyl acrylate, heptyl acrylate, octyl acrylate, C10 isoamyl guerbet acrylate, 2-propyl pentyl acrylate, 1-propylheptyl acrylate, lauryl acrylate, C5 to C20 alkyl methacrylates such as n- and isopentyl methacrylate, n-hexyl methacrylate, heptyl methacrylate, octyl methacrylate, C10 Isoamyl guerbet methacrylate, 2-propylpentyl methacrylate, 2-propylheptyl methacrylate, lauryl methacrylate, vinyl esters of unbranched or branched carboxylic acids having 2 to 11 C atoms, such as vinyl propionate, vinyl butyrate, 1-methylvinyl acetate, vinyl pivalate and vinyl esters of α-branched monocarboxylic acids 9 C atoms (VeoVa9 ^R , trade name of the company Shell), such as vinyl 2-ethylhexanoate, vinyl laurate, vinyl esters of α-branched monocarboxylic acids having 10 or 1 1 C atoms (VeoVa10 ^R , VeoVa1 1 ^R , trade name of the company Shell) and vinyl esters of branched monocarboxylic acids having 10 to 13 C atoms (Exxar Neo12), C 1 -C 20 -vinyl ethers, such as methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, pentyl vinyl ether, hexyl vinyl ether, heptyl vinyl ether, Octyl vinyl ether, nonylyl vinyl ether, decyl vinyl ether, etc, butadiene, vinylidene chloride and butanediol monoacrylate. Preferably, in the case of the monomers M2, the pair of n-butyl acrylate / ethylhexyl acrylate is used.

It may optionally continue to be used in minor amounts, for example in less than 10 wt .-%, preferably less than 8 wt .-%, more preferably less than 6 wt .-%, monomers M3.

Examples of these further monomers M3 are ethylenically unsaturated mono- and dicarboxylic acids, such as acrylic acid, methacrylic acid, itaconic acid, fumaric acid and maleic acid, acontic acid, mesaconic acid, crotonic acid, citraconic acid, acryloyloxypropionic acid, methacrylylpropionic acid, vinylacetic acid, monomethylitaconate, mono-methylfumarate , Monobutyl fumarate, acrylic anhydride, methacrylic anhydride, maleic anhydride, or itaconic anhydride, acrylamidoglycolic acid and methacrylamidoglycolic acid, acrylamide, methacrylamide, and isopropylacrylamide, substituted (meth) acrylamides, such as N, N-dimethylamino (meth) acrylate; 3-dimethylamino-2,2-dimethylpropyl-1 - (meth) acrylate, N-dimethylaminomethyl (meth) acrylamide, N- (4-morpholinomethyl) (meth) acrylamide, diacetone acrylamide; Acetoacetoxvethvlmethacrylat; N-methylol (meth) acrylamide, polyethylene oxide (meth) acrylate, methoxypolyethylene oxide (meth) acrylate, acrolein, methacrolein; N- (2-methacryloxyethyl) ethylene urea, 1- (2- (3-allyloxy-2-hydroxypropylamino) ethyl) -imidazolidin-2-one, ureido (meth) acrylate, 2-ethyleneureidoethyl methactylate.

Also suitable are: ethylenically unsaturated, hydroxyalkyl-functional comonomers, such as methacrylic acid and acrylic acid hydroxyalkyl esters with C 1 - to C 8 -alkyl radical, such as hydroxyethyl, hydroxypropyl or hydroxybutyl acrylate or methacrylate; Hydroxyethyl (meth) acrylate and hydroxypropyl (meth) acrylates; 4-hydroxybutyl acrylate, 4-hydroxybutyl methacrylate, glycidyl (meth) acrylate, and N-vinylpyrrolidone, vinylimidazole.

Particular preference is given to using acrylic acid, methacrylic acid, acrylamide, hydroxyethyl (meth) acrylate and hydroxypropyl (meth) acrylate.

Further examples of the monomers M3 are phosphorus-containing monomers z. As vinylphosphonic acid and allylphosphonic. Also suitable are the mono- and diesters of phosphonic acid and phosphoric acid with hydroxyalkyl (meth) acrylates, especially the monoesters. Also suitable are diesters of phosphonic acid and phosphoric acid which are simply acrylate with a hydroxyalkyl (meth) and additionally simply with a different alcohol, for. As an alkanol, are esterified. Suitable hydroxyalkyl (meth) acrylates for these esters are those mentioned below as separate monomers, in particular

2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, etc. Corresponding dihydrogen phosphate ester monomers include phosphoalkyl (meth) acrylates such as 2-phosphoethyl (meth) acrylate. 2-phosphopropyl (meth) acrylate, 3 Phosphopropyl (meth) acrylate, phosphobutyl (meth) acrylate and 3-phospho-2-hydroxypropyl (meth) acrylate. Also suitable are the esters of phosphonic acid and phosphoric acid with alkoxylated hydroxyalkyl (meth) acrylates, eg. B. the ethylene oxide condensates of (meth) acrylates, such as H ₂ C = C (CH 3) COO (CH ₂ CH ₂ 0) nP (OH) 2 and

H ₂ C = C (CH 3) COO (CH ₂ CH ₂ O) n P (= O) (OH) 2 where n is 1 to 50. Also suitable are phosphoalkyl crotonates, phosphoalkyl maleates, phosphoalkyl fumarates, phosphodialkyl (meth) acrylates, phosphodialkyl crotonates and allyl phosphates. Further suitable phosphorous group-containing monomers are described in WO 99/25780 and US 4,733,005, to which reference is hereby made.

Also suitable are vinylsulfonic acid, allylsulfonic acid, sulfoethyl acrylate, sulfoethyl methacrylate, sulfopropyl acrylate, sulfopropyl methacrylate, 2-hydroxy-3-acryloxypropylsulfonic acid, 2-hydroxy-3-methacryloxypropylsulfonic acid, styrenesulfonic acids and 2-acrylamido-2-methylpropanesulfonic acid. Suitable styrenesulfonic acids and derivatives thereof are styrene-4-sulfonic acid and styrene-3-sulfonic acid and the alkaline earth or alkali metal salts thereof, e.g. As sodium styrene-3-sulfonate and sodium styrene-4-sulfonate, poly (allyl glycidyl ether) and mixtures thereof, in the form of various products called Bisomer ® Laporte Performance Chemicals, UK. This includes z. Bisomer® MPEG 350 MA, a methoxypolyethyl-glycol monomethacrylate.

The functional groups of the monomers contribute to the mediation of the colloidal stabilization of the composition, in particular even if the entire formulation also contains fillers, e.g. Contains calcium carbonate or other. In this case, the crosslinking takes place either by reaction with one another or by addition of a further crosslinking agent. Preferably, the crosslinking takes place only after the actual film formation.

Monomers, which usually increase the internal strength of films of aqueous polymer dispersions, normally have at least one epoxy, hydroxyl, N-methylol, carbonyl or at least two non-conjugated ethylenically unsaturated double bonds. Examples of these are N-alkylolamides of .alpha.,. Beta.-monoethylenically unsaturated carboxylic acids having from 3 to 10 carbon atoms and also esters thereof having alkanols having from 1 to 4 carbon atoms, of which N-methylolacrylamide and N-methylolmethacrylamide are very particularly preferred, two vinyl radical-containing monomers, two vinylidene radical-containing monomers and two alkenyl radicals having monomers. Particularly advantageous are the diesters of dihydric alcohols with α, β-monoethylenically unsaturated monocarboxylic acids, of which the acrylic and methacrylic acids are preferred. Examples of such two non-conjugated ethylenically unsaturated double bonds monomers are alkylene glycol diacrylates and dimethacrylates such as ethylene glycol diacrylate, 1, 3-Butylenglykoldiacrylat, 1, 4-Butylenglykoldiacrylat and propylene glycol diacrylate, divinylbenzene, vinyl methacrylate, vinyl acrylate, allyl methacrylate, allyl acrylate, diallyl maleate, diallyl fumarate , Methylenebisacrylamide, cyclopentadienyl acrylate or trialyl cyanurate. Functional crosslinker groups are, for example, keto, aldehyde and / or acetoacetoxy carbonyl groups and the subsequently added, formulated crosslinking agents can be a polyamine or polyhydrazide such as adipic dihydrazide (ADDH), oxalic acid dihydrazide, phthalic dihydrazide, terephthalic dihydrazide, isophoronediamine and 4,7-dioxadecane 1, 1 O-Dia-min or a cross-linking agent which carries semi-carbazide or hydrazine functional groups. Alternatively, the polymer could carry hydrazide functional groups and the subsequently formulated crosslinker could contain ketofunctional groups.

The functional groups can be carboxyl and the subsequently formulated crosslinker could comprise aziridine, epoxy or carbodiimide functional groups, or functional groups can be silane-functional groups and the subsequently formulated crosslinking agent may also ^contain silane functional groups "

The functional groups can also be ureido groups and the subsequently added crosslinking agent is a polyaldehyde, for example an α, ω-dialdehyde having one to ten C atoms, such as glyoxal, glutaric dialdehyde or malonic dialdehyde or their acetals and hemiacetals. See EP 0789724.

In this case, the crosslinking takes place either by reaction with one another or by addition of a further crosslinking agent. Preferably, the crosslinking takes place only after the actual film formation. It is important not to use too much additional crosslinking agent as this is too

Residual crosslinking agent residues may result. On the other hand, too little crosslinking agent can lead to a soluble coating. It is important not to use too much additional crosslinking agent, as this may lead to residual crosslinking agent residues. Of course, combinations of the various functional groups and crosslinking mechanisms are also possible.

Vinyl monomers containing crosslinking groups are, for example, allyl, glycidyl or acetoacetoxy esters, acetoacetoxyamides, keto and aldehyde-functional vinyl monomers, keto-containing amides such as diacetone acrylamide or silane (meth) acrylic monomers.

Preferred crosslinking vinyl monomers are acetoacetoxyethyl methacrylate (AAEM), diacetone acrylamide (DAAM), and silane (meth) acrylic monomers; most preferred DAAM.

Preferred crosslinking mechanisms include crosslinking of silane-functional groups and crosslinking of keto-functional with hydrazide-functional groups.

Most preferred is the combination of DAAM and ADDH crosslinking. The weight ratio of the monomers M1 to M2 to M3 depends on the preferred applications of the binder and is thus significantly higher than the glass transition temperature of the polymers prepared from the mixture of all monomers. Examples of preferred mixtures for facade paints and roof coatings include:

a) Very soft, elastic binder proportions in hybrid (Tg about -40 - -20 ° C): 10 to 20%

Monomers M1 (calculated on the basis of methyl methacrylate / styrene), 70-88% of monomers M2 and 0.1 to 10% of monomers M3 (calculated on n-butyl acrylate 2-ethylhexyl acrylate), the styrene amount of the monomers M1 being in the range of 5-10 % lies.

b) Soft, selbstverfilmende, elastic binder proportions in the hybrid (Tg about 0 ° C): 35 bis

50% of monomers M1 (based on methyl methacrylate styrene), 49-59% of monomers M2 and 0.1 to 10% of monomers M3 (calculated on n-butyl acrylate / 2-ethylhexyl acrylate), the styrene amount of the monomers M1 being in the range of 10 -20% is.

c) binder proportions for elastic roof coatings and for facade paints and

Plasters which may require small amounts of film-forming assistant (Tg about 15-20 ° C): 37 to 47% monomers M1 (based on methyl methacrylate / styrene), 48-58% monomers M2 and 0.1 to 10% monomers M3 (calculated on n-butyl acrylate / 2-ethylhexyl acrylate), wherein the amount of styrene in the monomer M1 in the range of

10-25% is.

d) Binder proportions for flexible roof coatings as well as facade paints and plasters requiring larger proportions of film-forming aids (Tg about 30-40 ° C): 60 to 70% monomers M1 (based on methyl methacrylate / styrene), 24-34% monomers M2 us 0.1 to 10% of monomers M3 (calculated on n-butyl acrylate / 2-ethylhexyl acrylate), wherein the amount of styrene in the monomer M1 is in the range of 10-25%.

Other preferred combinations can easily be determined by the above listing for glass transition temperatures which were not mentioned.

Preferred monomer combinations M1 are the pairs styrene / methyl methacrylate or cyclohexyl methacrylate / methyl methacrylate and for the monomer combinations M2

the pair of n-butyl acrylate / ethylhexyl acrylate. Of the monomers M1, it is possible to use between 0 and 20% by weight, based on the total amount of the monomers M1, M2 and M3, of acrylonitrile and / or methacrylonitrile.

For ecological reasons, a filming of the hybrid binder in the range of 0 to 40 ° C is desired, so that no or only small amounts of a film-forming agent are needed. According to the invention, therefore, hybrid binders are preferably (calculated) with a minimum film-forming temperature of -40 ° C to + 40 ° C. Particular preference is given to hybrid binders having a minimum film-forming temperature of -40 ° C. to 20 ° C. (calculated). The polyurethane-polyacrylate hybrid dispersions are obtained by free-radical polymerization of an acrylate polymer A1 in the presence of at least one polyurethane (P1), at least one initiator system, wherein the at least one polyurethane (P1) has a content of polyalkylene oxide of at least 10 g / kg polyurethane and a content of a sulfonated raw material of at least 25 mmol per kg of polyurethane, the acrylate polymer has a glass transition temperature of at least -50 ° C to 50 ° C, the mass fraction of the polyurethane is at least 5% and at most 99.99% with respect to the entire hybrid polymer , In the preparation of the polyurethane-polyacrylate dispersion, the polyurethane dispersion is first prepared, and then this polyurethane dispersion is used as a seed for the acrylate dispersion. The acrylate dispersion is preferably polymerized in a semi-batch process. The preparation of aqueous polymer dispersions by the process of free-radical emulsion polymerization is known per se (compare Houben-Weyl, Methods of Organic Chemistry, Volume XIV, Makromolekulare Stoffe, 1 c, pages 133ff).

For the polyurethane-polyacrylate hybrid dispersions of the invention, (a) the polyurethane (P1) is first prepared, and (b) the polyurethane (P1) is used as seed for the preparation of the acrylate polymer (A1).

A feed process in which the polyurethane (P1) and a part of the initiator are initially polymerized is polymerized for a few minutes and then the polymerization is carried out by continuously adding the remaining initiator and the monomers M1, M2 and M3, as a pure monomer mixture or in the form a monomer emulsion in water, carried out until essentially complete conversion.

In a further embodiment, the polyurethane (P1) is initially introduced and a portion of the monomer mixture and a portion of the initiator are metered at the same time for starting. After complete or partial abreaction of the monomers, the remainder of the monomer mixture is then fed and the polymerization is essentially complete

Sales led.

The monomers can be distributed to several feeds and with variable

Dosage rate and / or variable content of one or more monomers are provided.

In another embodiment, the polyurethane (P1) is added and the total amount of initiator added to start. After a few minutes, the monomers M1, M2 and M3, as a pure monomer mixture or in the form of a monomer emulsion in water, are added and the polymerization is carried out until substantially complete conversion.

In another embodiment, the polyurethane (P1) is added and the total amount of the oxidation component of a redox initiator system is added. Subsequently, the monomers M1, M2 and M3, as pure monomer mixture or in the form of a monomer emulsion in water, are metered in and the reducing agent component is also metered in parallel. te of a redox initiator system and performs the polymerization to substantially complete conversion.

In a further embodiment, the polyurethane (P1) is introduced and the oxidation component of a redox initiator system, the monomers M1, M2 and M3, as pure monomer mixture or in the form of a monomer emulsion in water, are metered in and, in parallel, also the reducing agent component of a redox initiator system and conducts the polymerization to essentially complete conversion. In all embodiments, the monomers can be distributed to multiple feeds and provided with variable metering rate and / or variable content of one or more monomers.

Optionally, molecular weight regulators may also be present. Due to the presence of regulators in a polymerization chain termination and start of a new chain by the resulting new radical usually reduces the molecular weight of the resulting polymer and in the presence of crosslinkers also reduces the number of crosslinks (crosslink density). If the concentration of regulators is increased in the course of polymerisation, the crosslinking density is further reduced in the course of the polymerization.

Such molecular weight regulators are known, for example they may be mercapto compounds, such as preferably tertiary dodecylmercaptan, n-dodecylmercaptan, isooctylmercaptopropionic acid, mercaptopropionic acid, dimeric α-methylstyrene, 2-ethylhexylthioglycolic acid ester (EHTG), 3-mercaptopropyltrimethoxysilane ( MTMO) or terpinolene. The molecular weight regulators are known and described for example in Houben-Weyl, Methods of Organic Chemistry, Vol. XIV / 1, p.297 ff., 1961, Stuttgart.

The polymerization is carried out according to the invention at a temperature of 60 to 110.degree. C., preferably at 65 to 100.degree. C., particularly preferably at 70 to 90.degree. The aqueous polymer dispersion thus obtained preferably has a solids content of from 30 to 65, particularly preferably from 35 to 55,% by weight.

The preparation of the acrylate dispersion according to the invention is carried out by emulsion polymerization. In the emulsion polymerization, ethylenically unsaturated compounds (monomers) are polymerized in water, with ionic and / or nonionic emulsifiers and / or protective colloids or stabilizers usually being used as surface-active compounds for stabilizing the monomer droplets and the polymer particles later formed from the monomers. According to the invention, however, the polymerization takes place with low emulsifier content. Preferably, a total of less than 2.5 or less than 2.0 wt .-% emulsifier, in particular less than 1, 5 wt .-%, based on the solids content of the polymer dispersion used. The preparation of the polymer dispersion is usually carried out in the presence of at least one surface-active compound. A detailed description of suitable protective colloids can be found in Houben-Weyl, Methods of Organic Chemistry, Volume XIV / 1, Macromolecular Materials, Georg Thieme Verlag, Stuttgart, 1961, p. 41 1 to 420. Suitable emulsifiers are also found in Houben-Weyl, Methods of Organic Chemistry, Volume 14/1, Macromolecular Materials, Georg Thieme Verlag, Stuttgart, 1961, pages 192 to 208.

Suitable emulsifiers are both anionic, cationic and nonionic emulsifiers. Emulsifiers whose relative molecular weights are usually below those of protective colloids are preferably used as surface-active substances. In particular, it has proven useful to use exclusively anionic emulsifiers or a combination of at least one anionic emulsifier and at least one nonionic emulsifier. Useful nonionic emulsifiers are araliphatic or aliphatic nonionic emulsifiers, for example ethoxylated mono-, di- and trialkylphenols (EO degree: 3 to 50, alkyl radical: C4-C10), ethoxylates of long-chain alcohols (EO degree: 3 to 100, alkyl radical: Cs -Cse) and polyethylene oxide / polypropylene oxide homo- and copolymers. These may contain randomly distributed alkylene oxide units or in copolymerized form in the form of blocks. Well suited z. B. EO / PO block copolymers. Preference is given to ethoxylates of long-chain alkanols (alkyl radical C1-C30, average degree of ethoxylation 5 to 100) and, with particular preference, those having a linear C 12 -C 20 -alkyl radical and a mean degree of ethoxylation of from 10 to 50 and also ethoxylated monoalkylphenols. Suitable anionic emulsifiers are, for example, alkali metal and ammonium salts of alkyl sulfates (alkyl radical: C8-C22), of sulfuric monoesters of ethoxylated alkanols (EO degree: 2 to 50, alkyl radical: C12-C18) and ethoxylated alkylphenols (EO degree: 3 to 50, alkyl radical: C4-C9), of alkylsulfonic acids (alkyl radical: C12-C18) and of alkylarylsulfonic acids (alkyl radical: C9-C18). Further suitable emulsifiers can be found in Houben-Weyl, Methods of Organic Chemistry, Volume XIV / 1, Macromolecular substances, Georg-Thieme-Verlag, Stuttgart, 1961, pp. 192-208. Also suitable as anionic emulsifiers are bis (phenylsulfonic acid) ethers or their alkali metal or ammonium salts which carry a C ₄ -C ₂ -alkyl group on one or both aromatic rings. These compounds are well known, for. From US-A-4,269,749, and commercially available, for example as Dowfax® 2A1 (Dow Chemical Company).

Suitable cationic emulsifiers are preferably quaternary ammonium halides, e.g. B. trimethylcetylammonium chloride, methyltrioctylammonium chloride, Benzyltriethylammonium- chloride or quaternary compounds of N-C6-C2o-alkylpyridines, -morpholinen or - imidazoles, z. B. N-Laurylpyridinium chloride.

It is also possible to add customary auxiliaries and additives to the polymer dispersions. These include, for example, the pH-adjusting substances, reduction and Bleaching agents, such as. For example, the alkali metal salts of hydroxymethanesulfinic acid (eg Rongalit® C from BASF Aktiengesellschaft), complexing agents, deodorants, odorants and viscosity modifiers, such as alcohols, eg. As glycerol, methanol, ethanol, tert-butanol, glycol, etc. These auxiliaries and additives can be added to the polymer dispersions in the template, one of the feeds or after completion of the polymerization.

The neutralization of acid groups of the first polymer is preferably carried out by at least partial addition of a neutralizing agent before and / or during the polymerization of the second stage. The neutralizing agent can be added in a common feed with the monomers to be polymerized or in a separate feed. After all monomers have been added, the amount of neutralizing agent required for neutralization of at least 10%, preferably 25 to 100% or 50 to 95% acid equivalents, is preferably contained in the polymerization vessel.

By the initiator system according to the invention is meant, for example, water-soluble or oil-soluble initiators with which the emulsion polymerization can be started. Water-soluble initiators are e.g. Ammonium and alkali metal salts of peroxodisulfuric acid, e.g. Sodium peroxodisulfate, hydrogen peroxide or organic peroxides, e.g. tert-butyl hydroperoxide or water-soluble azo compounds, e.g. 2,2'-azobis (2-amidinopropane) dihydrochloride or 2,2'-azobis (Ν, Ν'-dimethyleneisobutyamidine). Also suitable as an initiator are so-called reduction-oxidation (redox) initiator systems. The redox initiator systems consist of at least one mostly inorganic reducing agent and one inorganic or organic oxidizing agent. The oxidation component is e.g. to the above-mentioned initiators for emulsion polymerization. The reducing component is e.g. alkali metal salts of sulfurous acid, e.g. Sodium sulfite, sodium hydrogen sulfite, alkali metal salts of the dihydrogenic acid, such as sodium disulfite, bisulfite addition compounds of aliphatic aldehydes and ketones, such as acetone bisulfite or reducing agents, such as hydroxymethanesulfinic acid and salts thereof, or ascorbic acid. The red-ox initiator systems can be used with the concomitant use of soluble metal compounds whose metallic component can occur in multiple valence states. Typical redox initiator systems are e.g. Ascorbic acid / iron (II) sulfate / sodium peroxodisulfate, tert-butyl hydroperoxide / sodium disulfite, tert-butyl hydroperoxide / Na-hydroxymethanesulfinic acid. The individual components, e.g. the reducing component may also be mixtures e.g. a mixture of the sodium salt of hydroxymethanesulfinic acid and sodium disulfite.

Typical oil-soluble free-radical initiators are peroxo and azo compounds, such as tert-butyl perpivalate, tert-butyl peroxyneodecanoate, tert-amyl peroxypivalate, dilauryl peroxide, tert-amyl peroxy-2-ethyl hexanoate, tert-amyl perneodecanoate, 2,2'-azobis (2 , 4-dimetyl) valeronitrile, 2,2'-azobis (2-methylbutyronitrile), di-octanoyl peroxide, di-decanoyl peroxide, di-acetyl peroxide, di-benzoyl peroxide, tert-butyl per-2-ethylhexanoate, di-tert. butyl peroxide, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane, dimethyl 2,2-azobisisobutyrate, azobis (2,4-dimethylvaleronitrile), azobis (isobutyronitrile), 2,2 Azobis (2-methyl-butyronitrile), and cumene hydroperoxide. NEN. These oil-soluble starters can either thermally decompose on their own or in mixtures or decompose by the addition of reducing agents, as described in the water-soluble starters. Particularly preferred free radical initiators are di- (3,5,5-trimethylhexanoyl) peroxide, 4,4'-

Azobisisobutyronitrile, tert-butyl perpivalate and dimethyl 2,2-azobisisobutyrate. These have a half-life of 10 hours in a temperature range of 30 to 100 ° C.

The initiators mentioned are usually used in the form of aqueous solutions or dispersions or as an oily substance with or without a solvent, the lower concentration being determined by the amount of water acceptable in the dispersion and the upper concentration by the solubility of the compound in question. In general, the concentration of active initiators is from 0.1 to 30% by weight, preferably from 0.2 to 20% by weight, particularly preferably from 0.3 to 10% by weight, based on the monomers to be polymerized. It is also possible to use a plurality of different initiators in the emulsion polymerization.

The polymerization medium may consist of water only, as well as of mixtures of water and thus miscible liquids such as methanol. Preferably, only water is used. The emulsion polymerization can be carried out both as a batch process and in the form of a feed process, including a stepwise or gradient procedure.

The manner in which the initiator is added to the polymerization vessel in the course of the free radical aqueous emulsion polymerization is known to one of ordinary skill in the art. It can be introduced both completely into the polymerization vessel, or used continuously or in stages according to its consumption in the course of the free radical aqueous emulsion polymerization. In detail, this depends on the chemical nature of the initiator system as well as on the polymerization temperature. Preferably, one part is initially charged and the remainder is supplied to the polymerization zone in accordance with the consumption

In the emulsion polymerization, aqueous dispersions of the polymer are generally obtained with solids contents of 15 to 75 wt .-%, preferably from 40 to 75 wt .-%, particularly preferably greater than or equal to 50 wt .-%. For a high space / time yield of the reactor, dispersions having the highest possible solids content are preferred. In order to achieve solids contents> 60 wt .-%, you should set a bimodal or polymodal particle size, otherwise the viscosity is too high, and the dispersion is no longer manageable. The generation of a new particle generation can be carried out, for example, by adding seed (EP 81083), by adding excess emulsifier amounts or by adding miniemulsions. Another benefit associated with low viscosity at high solids content is improved coating behavior at high solids levels. The generation of a new / new particle generation (s) can become a take place at any time. It depends on the particle size distribution desired for a low viscosity.

It is often advantageous if the aqueous polymer dispersion obtained after completion of the polymerization stages is subjected to an aftertreatment to reduce the residual monomer content. The aftertreatment is carried out either chemically, for example by completing the polymerization reaction by using a more effective radical initiator system (so-called postpolymerization) and / or physically, for example by stripping the aqueous polymer dispersion with steam or inert gas. Corresponding chemical and / or physical methods are familiar to the person skilled in the art [see, for example, DE-AS 12 48 943, DE-A 196 21 027, EP-A 771 328, DE-A 196 24 299, DE-A 196 21 027, DE-A. A 197 41 184, DE-A 197 41 187, DE-A 198 05 122, DE-A 198 28 183, DE-A 198 39 199, DE-A 198 40 586 and 198 47 1 15]. The combination of chemical and physical aftertreatment offers the advantage that in addition to the unreacted ethylenically unsaturated monomers, other interfering volatile organic components (the so-called VOCs [volatile organic compounds]) are removed from the aqueous polymer dispersion. The dispersions of the invention are preferably not chemically aftertreated. The individual components in the emulsion polymerization can be added to the reactor in the feed process from above, in the side or from below through the reactor bottom.

The aqueous hybrid dispersions obtainable by the process according to the invention have polymer particles which have a weight-average particle diameter D _w in the range> 10 and <500 nm, preferably> 20 and <400 nm and particularly preferably> 30 nm to <300 nm. The determination of the weight-average particle diameter is known to the person skilled in the art and is carried out, for example, by the method of the analytical ultracentrifuge. Weight-average particle diameter in this document is understood to mean the weight-average D _W 5o value determined by the method of the analytical ultracentrifuge (see, in this regard, SE Harding et al., Analytical Ultracentrifugation in Biochemistry and Polymer Science, Royal Society of Chemistry, Cambridge, Great Britain 1992 , Chapter 10, Analysis of Polymer Dispersions with Eight-Cell AUC Multiplexers: High Resolution Particle Size Distribution and Density Gradient Techniques, W. Mächtie, pp. 147-175).

The aqueous polyurethane-acrylate hybrid dispersions having weight-average particle diameters D _w <400 nm which are obtainable by the process according to the invention have surprisingly good flexibility, even at low temperatures, and are therefore particularly suitable as binders for flexible roof coatings and other paint applications.

Furthermore, the corresponding polymer powders can be obtained in a simple manner from the novel aqueous polymer dispersions (for example freeze drying or spray drying). These polymer powders obtainable according to the invention can likewise be obtained as a component in the manufacture of coatings for flexible roofing coatings and other paint applications, including the modification of mineral binders. The aqueous polymer dispersion usually has a solids content of 30 to 65 wt .-%, preferably 35 to 55 wt .-%, on.

The resulting aqueous polyurethane-polyacrylate hybrid dispersion can be used as such or mixed with other, usually film-forming, polymers as a binder composition in aqueous coating compositions.

Of course, the novel aqueous hybrid dispersions obtainable by the process according to the invention can also be used as a component in the production of adhesives, sealants, plastic plasters, paper coating slips, fiber webs, and coating compositions for organic substrates and for the modification of mineral binders.

Another object of the invention is a coating composition in the form of an aqueous composition containing

at least one polyurethane-polyacrylate hybrid dispersion according to the invention, as defined above,

optionally at least one organic filler and / or at least one organic pigment,

optionally at least one common adjunct, and

- Water.

The binder compositions according to the invention come in elastic paints, pasty tile adhesives, moisture-proof seals, floor covering adhesives, primers, cementitious sealing slurries, sealants, assembly adhesives or in flexible roof coatings,

preferably in aqueous paints, especially in flexible roof coatings and facade paints for use.

Fillers can be used to increase the opacity and / or to save on white pigments. To adjust the hiding power of the hue and the depth of shade, blends of color pigments and fillers are preferably used.

Suitable pigments are, for example, inorganic white pigments, such as titanium dioxide, preferably in rutile form, barium sulfate, zinc oxide, zinc sulfide, basic lead carbonate, antimony trioxide, lithopones (zinc sulfide + barium sulfate) or colored pigments, for example iron oxides, carbon black, graphite, zinc yellow, Zinc green, ultramarine, manganese black, antimony black, manganese violet, Paris blue or Schweinfurter green. In addition to the inorganic pigments, the emulsion paints of the invention may also organic color pigments, for. B. Sepia, cambogia, Kasseler brown, toluidine red, pararotene, Hansa yellow, indigo, azo dyes, anthraquinoid and indigoid dyes and dioxazine, quinacridone, phthalocyanine, isoindolinone and metal complex pigments. Also suitable are synthetic white pigments with air inclusions to increase light scattering, such as the Ropaque® and AQACell® dispersions. Also suitable are the Luconyl® grades from BASF SE, such as Lyconyl® yellow, Lyconyl® brown and Luconyl® red, in particular the transparent variants.

Suitable fillers are for. B. aluminosilicates such as feldspars, silicates such as kaolin, talc, mica, magnesite, tobermorite, xonolite, alkaline earth metal carbonates such as calcium carbonate, for example in the form of calcite or chalk, magnesium carbonate, dolomite, alkaline earth sulfates such as calcium sulfate, silicon dioxide, etc .. In flexible Roof coatings and in paints finely divided fillers are naturally preferred. The fillers can be used as individual components. In practice, however, filler mixtures have proven particularly useful, for. As calcium carbonate / kaolin, calcium carbonate / talc. Glossy coating compositions generally have only small amounts of very finely divided fillers or contain no fillers.

Finely divided fillers can also be used to increase the hiding power and / or to save on white pigments. To adjust the hiding power of the hue and the depth of shade, blends of color pigments and fillers are preferably used.

A particularly high breaking strength without particular disadvantages in the elongation at break is achieved with the hybrid binders according to the invention, if particularly finely divided fillers are used, e.g. Calcium carbonate with an average particle size of <2μηη. Such products are often already pre-dispersed as a slurry in water, which allows a particularly simple color production. Suitable calcium carbonate slurries are obtainable, for example, from Omya, Oftringen, Switzerland under the trade name Hydrorcarb, e.g. the type Hydrocarb 95 with an average particle size of 0.7 μηη.

The proportion of pigments can be described by the pigment volume concentration (PVK). Inventive, elastic roof coating agents have z. As a PVK in the range of 10 to 40, the binders are of course also suitable for clearcoat applications in which no or only very small amounts of pigments and / or fillers are added. The elasticity (elongation at break) is usually greater, the more binder is used in the coating.

The coating composition according to the invention for the flexible roof coating and aqueous coating compositions may contain, in addition to the polymer dispersion, further auxiliaries.

The usual auxiliaries include, in addition to the emulsifiers used in the polymerization, wetting or dispersing agents, such as sodium, potassium or ammonium polyphosphates, Alkali metal and ammonium salts of acrylic or maleic anhydride copolymers, polyphosphonates such as 1-hydroxyethane-1, 1-diphosphonsauresodium and Naphthalinsul- fonsÄuresalze, in particular their sodium salts. Further suitable auxiliaries are leveling agents, defoamers, biocides and thickeners. Suitable thickeners are z. B. Associative thickener, such as polyurethane thickener. The amount of thickener is preferably less than 1 wt .-%, more preferably less than 0.6 wt .-% thickener, based on solids content of the paint. Further suitable auxiliaries are film-forming aids or coalescing aids. Preference is given to, for example, white spirit, ethylene glycol, propylene glycol, glycerol, ethanol, methanol, water-miscible glycol ethers and their acetates, such as diethylene glycol, 1-methoxy-2-propanol, 2-amino-2-methyl-1-propanol, isooctanol, butylglycol, butyldiglycol, diethylene glycol - col-monobutyl ether, dipropylene glycol monomethyl or dipropylene glycol monobutyl ether, dipropylene glycol methyl ether, dipropylene glycol propyl ether, dipropylene glycol n-butyl ether, tripropylene glycol n-butyl ether, propylene glycol phenyl ether, butyl glycol acetate, butyl diglycol acetate, 2,2,4-trimethyl-1, 3 Pentandiolmonoisubutyrat, Disobutylester long-chain dicarboxylic acids such as Lusolvan® FBH or Tripropylenglykolmonoisobutyrat used. Further suitable auxiliaries are mineral binders, such as various cements, as well as tackifier resins, such as colophony resin, colophony resin esters or mixtures thereof.

The preparation of the paint according to the invention is carried out in a known manner by mixing the components in mixing devices customary for this purpose. It has proven useful to prepare an aqueous paste or dispersion from the pigments, water and optionally the adjuvants, and then first the polymeric binder, d. H. as a rule, to mix the aqueous dispersion of the polymer with the pigment paste or pigment dispersion. The paints according to the invention generally contain from 30 to 75% by weight and preferably from 40 to 65% by weight of nonvolatile constituents. These are to be understood as meaning all constituents of the preparation which are not water, but at least the total amount of binder, pigment and auxiliary agent, based on the solids content of the paint. The volatile constituents are predominantly water.

The paint of the invention can be applied in a conventional manner to substrates, for. B. by brushing, spraying, dipping, rolling, knife coating, etc.

It is preferably used as a flexible roof coating agent, ie for coating flat or inclined building parts. It may be mineral substrates such as plasters, plaster or plasterboard, masonry or concrete, wood, wood-based materials, metal or plastic, eg. As PVC, thermoplastic polyurethane, EPDM, epoxy resin, Polyurethane resin, acrylic resin or bitumen material act as a coating or sheet goods.

The paints of the invention are characterized by easy handling, good processing properties and improved elasticity. The paints are low in emissions. They have good performance properties, eg. B. good water resistance, good wet adhesion, good blocking resistance, good paintability, good weather resistance and they show a good course when applied. The tool used can be easily cleaned with water.

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

The solids contents were generally determined by drying a defined amount of the aqueous polymer dispersion (about 0.8 g) with the aid of the moisture analyzer HR73 from Mettler Toledo at a temperature of 130 ° C. to constant weight (about 2 hours). In each case two measurements were carried out. The specified value represents the mean value of these measurements.

The number-average particle diameters of the polymer particles were generally determined by dynamic light scattering on a 0.005 to 0.01 weight percent aqueous polymer dispersion at 23 ° C. by means of an Autosizers NC from Malvern Instruments, England. The average diameter of the cumulant analysis (cumulant z average) of the measured autocorrelation function (ISO Standard 13 321) is given. The glass transition temperature was determined in accordance with standard ISO 1 1357-2 at a heating rate of 20 K / min using the instrument "Q2000" from TA Instruments, Newcastle, Delaware, USA.

Examples of polyurethane dispersion

example 1

456.05 g of a polyester diol of adipic acid, neopentyl glycol and hexanediol-1, 6 of OH number 56

39.69 g of a butanol-initiated polyethylene oxide of OH number 15

0.1932 g of dibutyltin dilaurate were placed in a stirred flask and brought to 60 ° C. To this was added dropwise 132.05 g of 4,4'-diisocyanatodicyclohexylmethane and 67.69 g (0.3185 mol) of isophorone diisocyanate over 5 minutes. Then it was diluted with 1 17.20 g of acetone and stirred at 74 ° C for 1 hour. Thereafter, 20.30 g of 1,4-butanediol was added rapidly and stirring was continued at 74 ° C. After 2 hours, it was diluted with 500.98 g of acetone and cooled to 50 ° C. The NCO content was determined to be 1.01% by weight (calculated: 1.00% by weight). At 50 ° C., 30.81 g of a 50% strength aqueous solution of the sodium salt of 2-aminoethyl-2-aminoethanesulfonic acid are added within 5 minutes and continue for a further 5 minutes touched. It is then diluted at 50 ° C. within 24 minutes with 743.47 g of water and then chain-extended with 4.21 g of diethylenetriamine and 2.06 g of isophoronediamine in 36.92 g of water.

After distillation of the acetone, a finely divided dispersion having a solids content of about 45% and a particle size of 91.7 nm at a pH of 9.46 was contained.

Example PU / PA hybrid dispersion

Example 2

In a 4 l glass vessel with anchor stirrer, heating and cooling devices and various feeds were at 20 to 25 ° C (room temperature) and atmospheric pressure (1 atm 1, 013 bar absolute),

444.44 g of a polyurethane dispersion prepared from Example 1 and heated to 85 ° C. After addition of a solution of 0.1 g of sodium peroxodisulfate in 4 g of water is polymerized for 5 minutes and then the feeds 1 and 2 started simultaneously.

Feed 1 73.6 g of water

2.5 g of a 20 wt .-% aqueous solution of a Fettalkoholpolyethoxylats (Lutensol ^®

T082 from BASF SE)

6.67 g of a 15% by weight aqueous solution of sodium lauryl sulfate

40 g of styrene

58 g of n-butyl acrylate,

48 g of methyl methacrylate,

50 g of 2-ethylhexyl acrylate,

2 g of acrylic acid and

4 g of a 50 wt .-% aqueous solution of acrylamide

Inlet 2

0.9 g of sodium peroxodisulfate

35 g of water

The feed 1 is added uniformly with stirring at 85 ° C over 120 minutes and the feed 2 over 135 minutes.

Thereafter, the reaction mixture was allowed to react for a further 15 minutes at the aforementioned temperature and then the mixture was cooled to room temperature. Thereafter, the resulting aqueous polymer dispersion was neutralized with 5 g of a 10% by weight aqueous sodium hydroxide solution. The resulting polymer dispersion had a solids content of 50.5 wt .-%, a number average particle diameter of 273 nm. Example 3

81, 94 g of 2-butyl-2-ethyl-1,3-propanediol, 39.69 g of a butanol-initiated polyethylene oxide of OH number 15, 258.76 g of PolyTHF 2000 and 0.4 g of tin-free catalyst based on bismuth neodecanoate , 75% in acetone (Borchikat 315, OMG Borchers) were placed in a stirred flask and brought to 56 ° C. To this was added dropwise 78.9 g of bis (4-isocyanotocyclohexyl) methane and 66.4 IPDI over 5 minutes. It was then diluted with 97 g of acetone and stirred at 74 ° C for 2 hours and 35 minutes. Thereafter, 19.9 g of 1, 4 butanediol was added dropwise and stirred at 74 ° C. After 2 hours and 40 minutes, it was diluted with 417 g of acetone and cooled to 50 ° C. The NCO content was determined to be 1.25% by weight (calculated: 1.18% by weight).

At 50 ° C 30.3 g of a 50% aqueous solution of the sodium salt of 2-aminoethyl-2-aminoethanesulfonic acid is added within 5 minutes and stirred for a further 5 minutes. Then diluted at 50 ° C within 15 minutes with 660.6 g of water and then chain-extended with 4.12 g of DETA and 2.02 g of IPDA in 36.21 g of water.

After distillation of the acetone, a finely divided dispersion with about 44.5% solids content and 91, 8 nm particle size at a pH of 8.03.

Example 4

In a 4 l glass vessel with anchor stirrer, heating and cooling devices and various feeds were at 20 to 25 ° C (room temperature) and atmospheric pressure (1 atm ^ 1, 013 bar absolute)

317.1 g of a polyurethane dispersion prepared from Example 1 and 141 g of water and heated to 80 ° C. After addition of 14.7 g of methyl methacrylate is stirred at 80 ° C for 30 minutes. After addition of a solution of 1, 5 g of t-butyl hydroperoxide in 3 g of water and 0.06 g of L (+) - ascorbic acid in 4 g of water and 0.024 g of ammonia, 25% igpolymerized for 5 minutes and then the feeds 1 started up to 4 at the same time.

Inlet 1

30 g of styrene

43.5 g of n-butyl acrylate,

21, 3 g of methyl methacrylate,

37.5 g of 2-ethylhexyl acrylate,

1, 5 g of acrylic acid and feed 2

3 g of a 50% by weight aqueous solution of acrylamide

60 g of water Inlet 3

13.5 g of t-butyl hydroperoxide

27 g of water

Inlet 4

0.54 g of L (+) - ascorbic acid

36 g of water

0.216 g of ammonia, 25%

The feed 1 and 2 is added uniformly with stirring at 80 ° C over 120 minutes and feed 3 and 4 over 180 minutes.

Subsequently, the reaction mixture was cooled to room temperature. The polymer dispersion obtained had a solids content of 37.6 wt .-%, a number average particle diameter of 87 nm.

Example 5

In a 4 l glass vessel with anchor stirrer, heating and cooling devices and various feeds were at 20 to 25 ° C (room temperature) and atmospheric pressure (1 atm 1, 013 bar absolute)

464.04 g of a polyurethane dispersion prepared from Example 1 and heated to 85 ° C. After addition of a solution of 0.1 g of sodium peroxodisulfate in 4 g of water is polymerized for 5 minutes and then the feeds 1 and 2 started simultaneously.

Feed 1 73.6 g of water

T082 from BASF SE)

6.67 g of a 15% by weight aqueous solution of sodium lauryl sulfate

30 g of styrene

62 g of n-butyl acrylate,

45.5 g of methyl methacrylate,

56 g of 2-ethylhexyl acrylate,

2 g of acrylic acid and

2 g of 2-hydroxypropyl acrylate

0.5 g of vinyltriethoxysilane

2 g of acetoacetoxyethyl methacrylate

Inlet 2 0.9 g of sodium peroxodisulfate

35 g of water feed 3

3 g of t-butyl hydroperoxide, 10% in water

Inlet 4

3.51 g of acetone bisulfite

10 g of water

Subsequently, the reaction mixture was allowed to cool to 80 ° C., feed 3 was added and feed 4 was added dropwise in 60 minutes. Then the mixture cooled to room temperature. Thereafter, the resulting aqueous polymer dispersion was neutralized with 5 g of a 10 wt% aqueous sodium hydroxide solution. The resulting polymer dispersion had a solids content of 50.5 wt .-%, a number average particle diameter of 141 nm.

Example 6 In a 4 l glass vessel with anchor stirrer, heating and cooling devices and various feeds were heated at 20 to 25 ° C (room temperature) and atmospheric pressure (1 atm 1, 013 bar absolute)

179.8 g of a polyurethane dispersion from Example 3 and 90 g of water and heated to 85 ° C. After addition of a solution of 0.1 g of sodium peroxodisulfate in 4 g of water is polymerized for 5 minutes and then the feeds 1 and 2 started simultaneously.

Inlet 1

1 17.5 g of water

T082 from BASF SE)

6.67 g of a 15% by weight aqueous solution of sodium lauryl sulfate

40 g of styrene

58 g of n-butyl acrylate,

47.6 g of methyl methacrylate,

50 g of 2-ethylhexyl acrylate,

2 g of acrylic acid and

4 g of a 50 wt .-% aqueous solution of acrylamide 0.2 g of vinyltriethoxysilane

0.2 g of allyl methacrylate

Inlet 2

0.9 g of sodium peroxodisulfate

35 g of water

Inlet 3

3 g of t-butyl hydroperoxide, 10% in water

Feed 4 3.51 g of acetone bisulfite

10 g of water

Thereafter, the reaction mixture was allowed to cool to 80 ° C, feed 3 is added and feed 4 was added dropwise in 60 minutes. Then the mixture was cooled to room temperature. Thereafter, the resulting aqueous polymer dispersion was neutralized with 5 g of a 10% by weight aqueous sodium hydroxide solution. The polymer dispersion obtained had a solids content of 42.6% by weight, a number-average particle diameter of 162 nm.

Example 7

190 g of a polyurethane dispersion from Example 1, and presented 80 g of water and heated to 85 ° C. After addition of a solution of 0.1 g of sodium peroxodisulfate in 4 g of water is polymerized for 5 minutes and then the feeds 1 and 2 started simultaneously.

Inlet 1

87.88 g of water

T082 from BASF SE)

6.67 g of a 15% by weight aqueous solution of sodium lauryl sulfate

48 g of styrene

48 g of n-butyl acrylate, 51, 6 g of methyl methacrylate,

44 g of 2-ethylhexyl acrylate,

2 g of acrylic acid and

4 g of a 50 wt .-% aqueous solution of acrylamide

Inlet 2

0.9 g of sodium peroxodisulfate

35 g of water

Inlet 3

3 g of t-butyl hydroperoxide, 10% in water feed 4

acetone

Water The feed 1 is added uniformly with stirring at 85 ° C. for 120 minutes and the feed 2 over 135 minutes.

Thereafter, the reaction mixture was allowed to cool to 80 ° C, feed 3 is added and feed 4 was added dropwise in 60 minutes. Then the mixture cooled to room temperature. Thereafter, the obtained aqueous polymer dispersion was neutralized with 7 g of a 10% by weight aqueous sodium hydroxide solution. The resulting polymer dispersion had a solids content of 43.1 wt .-%, and an average glass transition temperature of 14.9 ° C.

Example 8

In a 4 l glass vessel with anchor stirrer, heating and cooling devices and various feeds were at 20 to 25 ° C (room temperature) and atmospheric pressure (1 atm 1, 013 bar absolute) and 183.9 g of a polyurethane dispersion of Example 1 and 215, 65 g of water submitted.

Furthermore, the following are submitted:

96.19 g of water

T082 from BASF SE)

6.67 g of a 15% by weight aqueous solution of sodium lauryl sulfate

41 g of styrene

58 g of n-butyl acrylate, 48 g of methyl methacrylate,

51 g of 2-ethylhexyl acrylate,

4 g of a 50 wt .-% aqueous solution of acrylamide Then 5.33 g of t-butyl perpivalate, 75% added in aliphatics and heated in 3 hours from 20 ° C to 93 ° C.

Then the mixture cooled to room temperature. Thereafter, the resulting aqueous polymer dispersion was neutralized with 2 g of a 10% by weight aqueous sodium hydroxide solution. The polymer dispersion obtained had a solids content of 38.8% by weight, a number average particle diameter of 103 nm.

Performance Tests a) Preparation of Color Formulations

From the components given in Table 1 (amounts in g), the roof-skin formulations based on the aqueous, exemplary polymer dispersions were prepared in the order from top to bottom with stirring with a disk stirrer at 400 to 2500 revolutions per minute.

Table 1 Roof skin formulation

Roof skin formulation A B C

Polymer Dispersion It. Example 2 109.0 1 14.0 1 14.0

Wetting agent ¹⁾ 0.8 0.8 0.8

Defoamer ²⁾ 1, 0 1, 0 1, 0

Dispersant ³⁾ 2,4 2,4 2,4

Filler ⁴⁾ 85.0

Filler ⁵⁾ 70.0

Filler ⁶⁾ 70.0

Water 10.0 10.0

Thickener ⁷⁾ 0.8 0.8 0.8

Defoamer ²⁾ 0.8 0.8 0.8

1) Lutensol TO 82, BASF SE, Ludwigshafen

2) Agitan 282, Münzing Chemie GmbH, Heilbronn

³⁾ Dispex CX 4320, BASF SE, Ludwigshafen

⁴⁾ Hydrocarb 95 ME, Omya, Oftringen, Switzerland

5 ⁾ Omyacarb 5 GU, Omya, Oftringen, Switzerland

⁶⁾ Omyacarb Extra CL, Omya, Oftringen, Switzerland

⁷⁾ Rheovis PU 1270, BASF SE, Ludwigshafen After addition of the last component, stirring was continued until everything was homogeneously mixed (about 10 minutes) and then the resulting roofing formulation was added for 0.5 minutes at 2000 rpm to a Speed Mixer DAC 400 FVZ from Hauschild.

The roof skin formulation has a solids content of about 63-67%, a pigment volume concentration of about 29 and a viscosity of 8000-10,000 mPas (Brookfield, spindle 6, 20 rpm). b) Preparation of coatings and test specimens

The above-mentioned roof skin formulation was applied with a doctor blade in a layer thickness of 1, 2 mm on a teflon-coated substrate. Subsequently, the coatings thus obtained for 7 days in a climate room at 50% relative humidity and 23 ° C were dried. The resulting dry film thickness is about 0.60 mm. After detaching the coating from the substrate, the required test specimens were punched out with appropriate punching iron. c) testing of tensile strength, tear strength and elongation at break

From the above-described coatings, size S1 shoulder bars were punched out using a punching iron.

The test was carried out in accordance with DIN 53504. The shoulder bars are clamped in a tensile / strain testing machine from Zwick and then pulled apart at a speed of 200 mm / min until tearing.

The more finely divided the calcium carbonate in the row of roofing formulations B -> C -> A is used, the greater the maximum force and the breaking strength of the dried formulation. The elongation at maximum force and the elongation at break is hardly dependent on the particle size of the filler.

Further formulations

Roof skin formulation D E F G H

Dispersion Example 4 5 6 7 8

Amount of dispersion [g] 62 58 63.5 63 65

Lutensol T082 0.4 0.4 0.4 0.4 0.4

Agitan 282 0.5 0.5 0.5 0.5 0.5 Dispex CX 4320 1.2 1.2 1.2 1.2 1.2

Omyacarb 5GU 29 36.5 34 34 31.5

Water 6 3 0 0 0

Rheovis PU 1270 0.5 0.2 0.4 0.4 0.4

Agitan 282 0.4 0.4 0.4 0.4 0.4

All roofing membrane formulations with the hybrid dispersions show a very high extensibility of more than 500% at breaking forces of about 2N / mm ² . By using an acrylate phase with a higher glass transition temperature, a greater elongation at break can be achieved (roof skin formulation G), at the expense of breaking elongation.

Applications and associated formulations with PU / PA hybrid

pasty moist floor base cement- sealantMontaFilter space coating re di compound adhesive adhesive sealant sludge sludge

PU / PA hybrid (50

%) 7-30 30-60 30-60 20-40 25-40 20-40 40-60

mineral

Binder 5-25

fillers

u. Pigments 69-92 39-69 30-60 33-69 35-79 34-54

Formulation Additives 0.5-2 0.5-2 0.5-2 0.5-2 0.5-2 0.5-2 0.5-4

Water 0-10 0-10 0-10 59-79 0-10

Tackifier resin 10-20 5-10

Claims

claims

Aqueous polyurethane-polyacrylate hybrid dispersion obtainable by free-radical polymerization of an acrylate polymer (A1) in the presence of at least one polyurethane (P1) and at least one initiator system, wherein the at least one polyurethane (P1) has a content of polyalkylene oxide and a content of a sulfonated raw material, and the acrylate polymer (A1) has a glass transition temperature of -50 ° C to 50 ° C, and the content by weight of the polyurethane is at least 5% and at most 95% with respect to the entire hybrid polymer.

Aqueous polyurethane-polyacrylate hybrid dispersion, according to claim 1, obtainable by free-radical polymerization of an acrylate polymer (A1) in the presence of at least one polyurethane (P1) and at least one initiator system, wherein the at least one polyurethane (P1) has a content of polyalkylene oxide of at least 10 g / kg polyurethane and a content of a sulfonated raw material of at least 25 mmol per kg of polyurethane and the acrylate polymer (A1) has a glass transition temperature of -50 ° C to 50 ° C, and the mass fraction of the polyurethane at least 5% and at most 95% with respect on the entire hybrid polymer.

Aqueous polyurethane-polyacrylate hybrid dispersion according to claim 1 or 2, characterized in that the acrylate dispersion (A1)

(a) at least two monomers M1 having a glass transition temperature> 25 ° C, and

(B) at least two monomers M2 having a glass transition temperature <25 ° C and

(c) optionally containing further monomers M3.

Aqueous polyurethane-polyacrylate hybrid dispersion according to any one of claims 1 to 3, characterized in that the monomers M1 are selected from the group of vinyl aromatic compounds, such as vinyl toluene, alpha- and para-methyl-styrene, alpha-butylstyrene, 4-n Butylstyrene, styrene, C1 to C4 alkyl methacrylates such as MMA,

Ethyl methacrylate, n-propyl methacrylate, i-propyl methacrylate, n-butyl methacrylate, t-butyl acrylate, i-butyl methacrylate, t-butyl methacrylate, t-butyl acrylate, cyclohexyl methacrylate, stearyl acrylate, vinyl acetate, vinyl chloride, ethylenically unsaturated nitriles such as acrylonitrile or methacrylonitrile, vinyl halides, Vinyl ethers z. As vinyl methyl ether or vinyl isobutyl ether or hydrocarbons having 4 to 8 carbon atoms and two olefinic double bonds.

Aqueous polyurethane-polyacrylate hybrid dispersion according to one of claims 1 to 4, characterized in that the monomers M1 are selected from styrene / methyl methacrylate or cyclohexyl methacrylate / methyl methacrylate.

Aqueous polyurethane-polyacrylate hybrid dispersion according to any one of claims 1 to 5, characterized in that the monomers M2 are selected from the group of C1 to C20 alkyl acrylates, such as methyl acrylate, ethyl acrylate, n- and i-propyl acrylate, n-, i- and sec-butyl acrylate, n- and i-pentyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, heptyl acrylate, octyl acrylate, C10-isoamyl guerbet acrylate, 2-propylpentyl acrylate, 1-propylheptyl acrylate, Lauryl acrylate, C5- to C20-alkyl methacrylates, such as n- and isopentyl methacrylate, n-hexyl methacrylate, heptyl methacrylate, octyl methacrylate, C10-isoamyl guerbet methacrylate, 2-propylpentyl methacrylate, 2-propylheptyl methacrylate, lauryl methacrylate, vinyl esters of unbranched or branched carboxylic acids with 2 to 1 1 C atoms, such as vinyl propionate, vinyl butyrate, 1-methylvinyl acetate, vinyl pivalate and vinyl esters of α-branched monocarboxylic acids having 9 C atoms (VeoVa9 ^R , trade name of Shell), such as vinyl-2-ethyl hexanoate, vinyl laurate, vinyl esters of α-branched monocarboxylic acids having 10 or 1 1 C atoms (VeoVa10 ^R , VeoVal 1 ^R , trade name of the company Shell) and vinyl esters of branched monocarboxylic acids having 10 to 13 C atoms (Exxar Neo12), C1- C20-vinyl ethers, such as methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, pentyl vinyl ether, hexyl vinyl ether, heptyl vinyl ether, octyl vinyl ether, nonyl vinyl vinyl ether, decyl vinyl ether, butadiene, vinylidene chloride d or butanediol monoacrylate.

7. Aqueous polyurethane-polyacrylate hybrid dispersion according to any one of claims 1 to 6, characterized in that the monomers M2 are selected from the group n-butyl acrylate / ethylhexyl acrylate.

Aqueous polyurethane-polyacrylate hybrid dispersion according to any one of claims 1 to 7, characterized in that the monomers M3 are selected from the group of acrylic acid, methacrylic acid, acrylamide, hydroxyethyl (meth) acrylate or hydroxypropyl (meth) acrylate.

Aqueous polyurethane-polyacrylate hybrid dispersion according to one of Claims 1 to 8, characterized in that the binder contains 10 to 20% of monomers M1 (based on methyl methacrylate styrene), 70-88% of monomers M2 (calculated on n-butyl acrylate / 2-ethylhexyl acrylate) and 0.1 to 10% of M3 monomers, the styrene level of monomers M1 being in the range of 5-15%.

10. Aqueous polyurethane-polyacrylate hybrid dispersion according to any one of claims 1 to 8, characterized in that the binder 35 to 50% monomers M1 (based on methyl methacrylate styrene), 49-59% monomers M2 (calculated on n-butyl acrylate) lat / 2-ethylhexyl acrylate), and 0.1 to 10% of monomers M3, wherein the amount of styrene in the monomers M1 is in the range of 10-20%.

1 1. Aqueous polyurethane-polyacrylate hybrid dispersion according to any one of claims 1 to 8, characterized in that the binder 37 to 47% monomers M1 (based on methyl methacrylate / styrene), 48 - 58% monomers M2 (calculated on n-Butylacry- lat / 2-ethylhexyl acrylate) and 0.1 to 10% of monomers M3, the styrene amount of monomers M1 being in the range of 10-25%.

12. Aqueous polyurethane-polyacrylate hybrid dispersion according to any one of claims 1 to 8, characterized in that the binder 60 to 70% monomers M1 (calculated on Based on methyl methacrylate styrene), 24-34% of monomers M2 (calculated on n-butyl acrylate / 2-ethylhexyl acrylate) and 0.1 to 10% of monomers M3, the styrene amount of the monomers M1 being in the range of 10-25%, contains.

Aqueous polyurethane-polyacrylate hybrid dispersion according to one of claims 1 to 12, characterized in that the acrylate dispersion (A1) contains main monomer combinations selected from the group consisting of styrene / 2-ethylhexyl acrylate, styrene / n-butyl acrylate or methyl methacrylate n-butyl acrylate ,

Aqueous polyurethane-polyacrylate hybrid dispersion according to any one of claims 1 to 13, characterized in that the polyurethane-polyacrylate hybrid dispersions, long-chain alkanol-initiated polyethylene oxides and sodium salts of 2-aminoethyl-2-amino-ethanesulfonic acid.

Process for the preparation of an aqueous polyurethane-polyacrylate hybrid dispersion according to one of Claims 1 to 14, characterized in that

(a) first, that polyurethane (P1) is produced

(B) and then the polyurethane (P1) is used as a seed for the preparation of the acrylate polymer (A1).

Process of the aqueous polyurethane-polyacrylate hybrid dispersion according to claim 14, characterized in that the acrylate dispersion is polymerized in a semi-batch process.

Use of the aqueous polyurethane-polyacrylate hybrid dispersion according to one of claims 1 to 14 as a binder in filled coating compositions.

Use of the aqueous polyurethane-polyacrylate hybrid dispersion according to claim 15 as a binder for pasty tile adhesives, moisture-proofing, floor covering adhesives, primers, cementitious sealing slurries, sealants, assembly adhesives, facade paints or for flexible roof coatings,

19. Use of the aqueous polyurethane-polyacrylate hybrid dispersion according to claim 15 as a binder for flexible roof coatings.

20. Use of the aqueous polyurethane-polyacrylate hybrid dispersion according to claim 15 as a binder for facade paints.

Use of the aqueous polyurethane-polyacrylate hybrid dispersion according to one of claims 17 to 20, characterized in that the PVK of the coating composition is 10 to 40.

22. Coating composition containing at least one aqueous polymer dispersion according to one of claims 1 to 14,

optionally at least one organic filler and / or at least one organic pigment,

optionally at least one common adjunct and

Water.

22. Coating composition according to claim 21, characterized in that the coating composition is a flexible roof coating.

A coating composition according to claim 21, characterized in that the coating composition is a facade paint.

24. A coated surface comprising a building material substrate having a major surface, at least a portion of which is covered with an aqueous polyurethane-polyacrylate hybrid dispersion according to any one of claims 1 to 14 as a final flexible roof coating composition.