Aqueous dispersion comprising polymer particles for improving the resistance of waterborne coatings

Abstract

The present invention relates in a first aspect to an aqueous dispersion comprising polymer particles, the polymer particles comprising(a) a polymer carrier obtained or obtainable from at least one ethylenically unsaturated monomer (a.1); and (b) a compound comprising at least one epoxy group, wherein the polymer carrier of (a) and the compound of (b) are not covalently bonded to each other; and wherein the aqueous dispersion comprises less than 1000 weight-ppm of an organic solvent.

Description

[0001] Aqueous dispersion comprising polymer particles for improving the resistance of waterborne coatings

[0002] The present invention relates in a first aspect to an aqueous dispersion comprising polymer particles, the polymer particles comprising(a) a polymer carrier obtained or obtainable from at least one ethylenically unsaturated monomer (a.1); and (b) a compound comprising at least one epoxy group, wherein the polymer carrier of (a) and the compound of (b) are not covalently bonded to each other; and wherein the aqueous dispersion comprises less than 1000 weight- ppm of an organic solvent. A second aspect of the invention is directed to a method for preparing an aqueous dispersion comprising polymer particles, the polymer particles comprising (a) a polymer carrier obtained or obtainable from at least one ethylenically unsaturated monomer (a.1); (b) a compound comprising at least one epoxy group; (c) optionally at least one surfactant; wherein the method comprises radical polymerization of the at least one ethylenically unsaturated monomer (a.1) within an aqueous emulsion comprising the compound comprising at least one epoxy group (b), the at least one ethylenically unsaturated monomer (a.1) and optionally the at least one surfactant (c), wherein the aqueous emulsion comprises less than 1000 weight-ppm of one or more organic solvent(s). A third aspect of the invention is related to an aqueous dispersion comprising polymer particles obtained or obtainable from the method of the second aspect. In a fourth aspect, the invention is directed to the use of the aqueous dispersion comprising polymer particles as additive for a water borne coating. A fifth aspect of the invention relates to a water-based paint composition, obtained or obtainable by adding the aqueous dispersion comprising polymer particles according to the first aspect to a water-based paint. A sixth aspect of the invention is directed to a water-based paint composition comprising polymer particles, the polymer particles comprising (a) a polymer carrier obtained or obtainable from at least one ethylenically unsaturated monomer (a.1), (b) a compound comprising at least one epoxy group, and (c) optionally at least one surfactant. In a seventh aspect, the invention is related to a coating, obtained or obtainable from application of a water-based paint composition according to the fifth or the sixth aspect to a surface.

[0003] State of the art

[0004] Water-borne coatings (synonymously named water-based coatings) are still inferior to solvent- borne coatings especially when it comes to resistance properties of the dry paint film (coating), for example, concerning water- and chemical-resistance, mechanical robustness, resistance against weathering conditions or resistance against corrosion. It is generally believed that a main reason for the still inferior properties of waterborne coatings compared to solvent-borne coatings is the fact that many components of waterborne coatings, especially binders, dispersants, surfactants, and rheology modifiers, inevitably contain polar functional groups to make them compatible in aqueous formulations to enable a storage stable wet paint. On the other side such polar functionalities, for example, carboxylic acid functionalities or salts thereof, which then remain in the dry paint film are detrimental for good resistance properties, especially against water and / or water vapor, what is a relevant exposure factor for almost all coatings under real life service conditions (for example, concerning rain, weathering, industrial cleaning, home cleaning, corrosion in humid environment, etc.).

[0005] A common approach to overcome the weak resistance properties is the use of chemical crosslinking in the form of 2-component (2K) or 1-component (1 K) formulation concepts, for example, using different crosslinker chemistries (via OH / lsocyanates, OH / melamines, CChH / epoxides, epoxy / amines, keto / amines, keto / hydrazides, etc.). Despite continuous technical progress, all such conventional crosslinking concepts still have fundamental disadvantages. They all require corresponding extra chemical functionalization of the main binder polymers and the use of often relative high amounts of reactive crosslinkers, for example, typically as 2K formulation concepts, which is a fundamental disadvantage in application, due to limitations in pot life. 1 K formulation concepts like with blocked isocyanates have the disadvantage that this requires extra thermal activation to achieve good crosslinking and thereby good improvement of resistance properties. In addition, most of the common reactive crosslinker chemistries have the disadvantage of being hazardous compounds, which are more and more disfavored for health, ecological and sustainability reasons. Especially when it comes to 1 K concept solutions, good storage stability and pot-life control can be very difficult to realize and is expensive due to the required functional resins and corresponding crosslinkers. In another approach, it has been described to add organic bases to improve wet scrub resistance, for example, in US 2012 / 115999 A1. However, organic amines generally are also disfavored from health, ecological reasons, and costs.

[0006] Furthermore, another problem when bringing property enhancing additives / reactants into waterborne coating formulations is the fact that many of these additives / reactants are non-polar, which makes them difficult, up to impossible, to incorporate into an aqueous system. In that regard, approaches have been proposed making use of encapsulation of additives / reactants into polymeric but more polar shells and emulsification of these encapsulated forms in aqueous systems. For example, WO 2011 / 012631 A1 discloses a concentrated aqueous polymer dispersion with an average particle size of less than 1000 nm comprising a polymer carrier, a non-polar organic phenolic antioxidant, and a surfactant. The process for the preparation of said concentrated aqueous polymer dispersion comprises miniemulsion technique, wherein a non-polar organic phenolic antioxidant is dissolved, emulsified or dispersed in at least one ethylenically unsaturated monomer (a.1); followed by preparation of a conventional oil in water emulsion in the presence of a non-ionic, cationic or anionic surfactant; followed by homogenization to a miniemulsion, wherein the droplets of the organic phase have an average diameter below 1000 nm; finally followed by polymerization of the miniemulsion using a polymerization initiator. The concentrated aqueous polymer dispersion is used as stabilizer against thermal, oxidative, or light- induced degradation of organic materials, which are susceptible to thermal, oxidative, or light induced degradation. EP 1 664 128 B1 is related to a concentrated aqueous polymer dispersion with an average particle size of less than 1000 nm comprising non-polar organic light stabilizers and the use thereof for stabilizing, inter alia, water-based coatings against light induced degradation. US 2017 / 0247570 A1 describes aqueous polymer-silicon oil hybrid composition and the use thereof for improving scrub-resistance of HASE-thickened paint formulations (HASE: hydro- phobically modified alkali soluble emulsion).

[0007] CA 2156468 A1 is related to a polymeric binder dispersed in water, the polymeric binder comprising a crosslinked epoxy-ester copolymer. EP 1 213 317 A2 relates to a method of making an aqueous dispersion of epoxy-functional particles comprising dissolving into a volatile solvent mixture an epoxy-functional resin and a polymer having an acid number between 30 and 200. The volatile solvent mixture comprises volatile solvent mixture comprises at least 60 percent of a water immiscible organic solvent and less than 20 percent by volume of a water miscible organic solvent. Even the solvent for the final dispersion, as sold or applied, even if water based, still comprises organic solvents. WO 2006 / 111290 A1 relates to coating agents, wherein an epoxy containing part is covalently bound to a polymer part. WO 2022 / 169796 A1 relates to a water-borne dispersion comprising polymeric multistage diketone-functionalised particles, wherein the final particles do not longer contain free epoxy groups.

[0008] Overall, there is still an ongoing need to find new solutions to improve the resistance properties of waterborne coatings, without the need of extra chemical functionalization of common binder polymers, without going to 2K formulation concepts and without the need of introducing extra curing triggers, like extra thermal activation steps. In addition, there is a need to realize improved paint film resistance properties without use of, or at least with reduced amounts of hazardous chemicals. From economical as well as technological view, it is also desirable to realize improvements of resistance properties of waterborne coating without the addition of high amounts of extra formulation components.

[0009] Therefore, it was an object of the present invention to provide an additive for improving resistance properties of waterborne coatings, which overcomes the above indicated disadvantages such as toxicity and which can be used in relatively small amounts. It was surprisingly found that these objects, especially improved paint film resistance properties, can be solved by a highly efficient waterborne additive which comprises polymer colloid particles dispersed in an aqueous system, wherein the polymer particles contain epoxy compounds, the later not being covalently bound to their polymeric shell. The additive can provide improved paint film resistance properties, when added to water-borne coatings formulations in relatively small amounts, while not altering other important paint parameters like rheology and water sensitivity while not requiring extra chemical functionalization of binder polymers commonly used in waterborne coatings.

[0010] In a first aspect, the invention relates to an aqueous dispersion comprising polymer particles, the polymer particles comprising

[0011] (a) a polymer carrier obtained or obtainable from at least one ethylenically unsaturated monomer (a.1);

[0012] (b) a compound comprising at least one epoxy group.

[0013] The additive, i.e. , the aqueous dispersion comprising polymer particles, comprises aqueous polymer colloid particles containing therein a compound comprising at least one epoxy group (also named herein “epoxy compound”). In the polymer particles, the polymer acts as carrier, to which the compound comprising at least one epoxy compound is attached and / or by which it is at least partially surrounded, without a covalent bond between compound comprising at least one epoxy compound and polymer. The polymer particles are for example prepared or preparable via miniemulsion polymerization technology of the at least one ethylenically unsaturated monomer (a.1) so that small polymer colloid particles are obtained. In this context, the term “attached and / or at least partially surrounded” relates to the fact that the water insoluble epoxy compound, even if not chemically bound, especially not covalently bonded, to the polymer, cannot migrate out of the polymer particle, as long as the surrounding water phase is present.

[0014] In some preferred embodiments of the aqueous dispersion, > 95 % of the polymer particles have a diameter of < 1000 nm, preferably in the range of from 20 to 1000 nm, more preferably in the range of from 20 to 500 nm, more preferably in the range of from 30 to 300 nm, determined by dynamic light scattering (DLS).

[0015] In some preferred embodiments, the aqueous dispersion comprises polymer particles, the polymer particles comprising

[0016] (a) a polymer carrier obtained or obtainable from at least one ethylenically unsaturated monomer (a.1);

[0017] (b) a compound comprising at least one epoxy group; wherein the polymer carrier of (a) and the compound of (b) are not covalently bonded to each other.

[0018] “Not covalently bonded to each other” means that there is no covalent bond between the polymer carrier of (a) and the compound comprising at least one epoxy group of (b).

[0019] (Volatile) Organic solvents

[0020] Preferably, the aqueous dispersion is free of volatile organic solvents. Preferably, less than 1000 weight-ppm of the aqueous dispersion are one or more volatile organic solvent(s). “Volatile” means that the organic solvent has at 1013 hPa a boiling point of less than 100 °C, preferably of less than 90 °C.

[0021] Thus, in some preferred embodiments, the aqueous dispersion comprises polymer particles, the polymer particles comprising

[0022] (a) a polymer carrier obtained or obtainable from at least one ethylenically unsaturated monomer (a.1);

[0023] (b) a compound comprising at least one epoxy group; wherein the polymer carrier of (a) and the compound of (b) are not covalently bonded to each other; and wherein the aqueous dispersion comprises less than 1000 weight-ppm of one or more volatile organic solvent(s).

[0024] More preferably less than 500 weight-ppm, more preferably less than 100 weight-ppm, more preferably less than 10 weight-ppm, more preferably less than 5 weight-ppm, of the aqueous dispersion are one or more volatile organic solvent(s), wherein the total weight of the aqueous dispersion are always 100 weight-%.

[0025] More preferably, the aqueous dispersion is free of organic solvents. Preferably, less than 1000 weight-ppm of the aqueous dispersion are one or more organic solvent(s).

[0026] Thus, in some preferred embodiments, the aqueous dispersion comprises polymer particles, the polymer particles comprising

[0027] (a) a polymer carrier obtained or obtainable from at least one ethylenically unsaturated monomer (a.1);

[0028] (b) a compound comprising at least one epoxy group; wherein the polymer carrier of (a) and the compound of (b) are not covalently bonded to each other; and wherein the aqueous dispersion comprises less than 1000 weight-ppm of one or more organic solvent(s).

[0029] More preferably less than 500 weight-ppm, more preferably less than 100 weight-ppm, more preferably less than 10 weight-ppm, more preferably less than 5 weight-ppm, of the aqueous dispersion are one or more organic solvent(s), wherein the total weight of the aqueous dispersion are always 100 weight-%.

[0030] More preferably, the one or more organic solvent(s) are selected from the group consisting of methyl acetate, ethyl acetate, n-propyl acetate, isobutyl acetate, n-butyl alcohol, chloroform, carbon tetrachloride, ethylene chloride, sec-butyl acetate, cyclohexanone, n-amyl alcohol, diethyl ether, methyl-n-propyl ketone, benzene, toluene, xylene, butoxyethyl acetate, acetone, methyl ethyl ketone, ethyl alcohol, methyl alcohol, isopropyl alcohol, n-propyl alcohol, tetrahydrofuran, ethylene glycol monomethyl ether, N-methylpyrrolidone, dimethylformamide, dimethyl sulfoxide, butyldiethoxy alcohol, dipropylene glycol methyl ether, and mixtures of two or more thereof.

[0031] Thus, the aqueous dispersion, aside from the components mentioned herein above, essentially consists of water. Preferably, at least 99 weight-%, preferably at least 99.5 weight-%, more preferably at least 99.8 weight-%, of the aqueous dispersion consist of polymer carrier of (a), compound comprising at least one epoxy group of (b), a non-volatile organic solvent, at least one surfactant, and water, wherein the total weight of the aqueous dispersion are always 100 weight-%.

[0032] Compound containing at least one epoxy group according to (b)

[0033] In some preferred embodiments of the aqueous dispersion, the compound containing at least one epoxy group according to (b) is present in an amount in the range of from 10 to 90 % by weight, preferably in the range of from 25 to 75 % by weight, more preferably in the range of from 40 to 60 % by weight based on the total weight of the polymer particle being 100 % by weight.

[0034] The compound containing at least one epoxy group according to (b) itself is poorly water soluble, i.e., when mixed with water at 25 °C, it forms a two-phase system determinable by visual inspection. In some preferred embodiments of the aqueous dispersion, the compound containing at least one epoxy group according to (b) is selected from mono-functional epoxy compound, multifunctional epoxy compound, epoxy-functional oligomer, epoxy-functional polymer, wherein an epoxy-functional polymer is preferably selected from the group consisting of epoxy-functional polysiloxane, epoxy-functional polyacrylate, epoxy-functional polybutadiene and mixtures of two or more thereof. An “oligomer” preferably comprises in the range of from 2 to 10 repetition units and a “polymer” preferably comprises > 10 repetition units. The term “low water solubility” preferably means a solubility of < 0.1 weight-%.

[0035] In some preferred embodiments of the aqueous dispersion, the compound containing at least one epoxy group according to (b) is selected from multifunctional epoxy compound, epoxy-functional oligomer and mixtures of these two, each having an epoxy-functional ity > 1 , more preferably > 2.

[0036] In some preferred embodiments of the aqueous dispersion, the compound containing at least one epoxy group according to (b) is selected from the group consisting of glycidylether of aliphatic alcohol, glycidylether of aromatic alcohol, glycidylether of multifunctional aliphatic alcohol, glycidylether of aromatic alcohol, wherein the aliphatic alcohol, aromatic alcohol, multifunctional aliphatic alcohol and aromatic alcohol each have more than 6 carbon atoms, diglycidylether of difunctional aliphatic cyclic alcohol, diglycidylether of difunctional aliphatic branched alcohol, diglycidylether of difunctional aliphatic linear alcohol, glycidylether of glyceride, glycidyl ether of partial glyceride, Bisphenol-A-diglycidylether, oligomer composed of Bisphenol-A-diglyc- idylether, Bisphenol-F-diglycidylether, oligomer composed of Bisphenol-F-diglycidylether, pol- ysiloxane-based structure with pending glycidyl groups, modified or unmodified novolac epoxy resin (phenol and cresol types), tetraglycidyl ether of tetraphenol ethane, glycidyl ether of mono- or polyfunctional alkoxylate, (meth)acrylic / styrenic copolymers with epoxy functionality, glyc- idylester of mono or polyfunctional carboxylic acid, (acrylic) (co)polymer / oligomer based on glyc- idyl(meth)acrylate as monomer, and mixtures of two or more thereof. A polysiloxane-based structure with pending glycidyl groups" means for example, a structure such as (R1)3Si-O-[- SiR1R2-O-]n-Si(R1)3, wherein R1is a C1 to C5 alkyl group, R2is -(CH2)m-glycidyl group, wherein n is an integer in the range of from 2 to 20 and m is an integer in the range of from 1 to 5.

[0037] In some preferred embodiments of the aqueous dispersion, the compound containing at least one epoxy group according to (b) is selected from the group consisting of bisphenol A diglycidyl ether, dodecyl / tetradecyl-glycidylether, branched C13-C15 glycidylether, glycidyl-hexa- decylether, (epoxycyclohexylethyl)methylsiloxane-dimethylsiloxane copolymer, linear polydimethylsiloxane with terminal epoxy groups, linear comb-type poylsiloxane with pending glycidyl groups having a functional group equivalent weight in the range of from 300 to 4000 g / mol, epoxidized soybean oil, diglycidyl ether based on cyclohexanedimethanol, monoglycidyl ether based on C13-C15-alkohols, bisphenol F-resin (phenol-formaldehyde polymer glycidyl ether), bisphenol A-resin having a viscosity in the range of from 5 to 20 Pas at 25 °C, diglycidyl ether epoxy resin, polyglycidyl ether of an alkenyl phenol formaldehyde novolac resin, 4,4'-Methylen- bis-(N , N-diglycidylanilin), tris(4-hydroxyphenyl)methane triglycidylether, poly(meth)acrylate with epoxy-functionality, copolymer based on (meth)acrylate and (methyl)styrene with epoxy-func- tionality, and mixtures of two or more thereof. Preferably, in each of these compounds containing at least one epoxy group, all previously present reactive carbon-carbon double bonds are completely epoxidised.

[0038] In a more preferred embodiment of the aqueous dispersion, the compound containing at least one epoxy group according to (b) is selected from the group consisting of bisphenol A diglycidyl ether, dodecyl / tetradecyl-glycidylether, branched C13-C15 glycidylether, glycidyl-hexa- decylether, (epoxycyclohexylethyl)methylsiloxane-dimethylsiloxane copolymer, linear polydimethylsiloxane with terminal epoxy groups, linear comb-type poylsiloxane with pending glycidyl groups having a functional group equivalent weight in the range of from 300 to 4000 g / mol, diglycidyl ether based on cyclohexanedimethanol, monoglycidyl ether based on C13-C15-alko- hols, bisphenol F-resin (phenol-formaldehyde polymer glycidyl ether), bisphenol A-resin having a viscosity in the range of from 5 to 20 Pas at 25 °C, diglycidyl ether epoxy resin, polyglycidyl ether of an alkenyl phenol formaldehyde novolac resin, 4, 4'-Methylen-bis-(N, N-diglycidylanilin), tris(4-hydroxyphenyl)methane triglycidylether, poly(meth)acrylate with epoxy-functionality, copolymer based on (meth)acrylate and (methyl)styrene with epoxy-functionality, and mixtures of two or more thereof. Preferably, in each of these compounds containing at least one epoxy group, all previously present reactive carbon-carbon double bonds are completely epoxidised.

[0039] In a more preferred embodiment of the aqueous dispersion, the compound containing at least one epoxy group according to (b) is selected from the group consisting of dodecyl / tetradecyl- glycidylether, branched C13-C15 glycidylether, glycidyl-hexadecylether, (epoxycyclo- hexylethyl)methylsiloxane-dimethylsiloxane copolymer, linear polydimethylsiloxane with terminal epoxy groups, linear comb-type poylsiloxane with pending glycidyl groups having a functional group equivalent weight in the range of from 300 to 4000 g / mol, diglycidyl ether based on cyclohexanedimethanol, monoglycidyl ether based on C13-C15-alkohols, tris(4-hydroxyphenyl)me- thane triglycidylether, poly(meth)acrylate with epoxy-functionality, and mixtures of two or more thereof. Preferably, in each of these compounds containing at least one epoxy group, all previously present reactive carbon-carbon double bonds are completely epoxidised.

[0040] The expression “(meth)acrylate” means methacrylate as well as acrylate. “(Methyl)styrene” means styrene as well as methyl substituted styrene, the later preferably being alpha-methyl styrene.

[0041] In some preferred embodiments of the aqueous dispersion, the compound containing at least one epoxy group according to (b) is selected from the group consisting of epoxide, which is derived from a mono or multi unsaturated nonpolar compound by epoxidation of the corresponding double bond(s), preferably selected from the group consisting of unsaturated non-polar compound of natural origin, the unsaturated non-polar compound of natural origin preferably being selected from the group consisting of sunflower oil, tall oil, soy-bean oil, castor oil, linseed oil, palm oil, rapeseed oil, cashew nutshell liquid, and mixtures of two or more thereof, cardanol, natural rubber, sucrose soyate, terpene based compound, and mixtures of two or more thereof. Preferably, the epoxide is formed completely, i.e. all corresponding double bond(s) are completely reacted to epoxide(s).

[0042] Ethylenically unsaturated monomer (a. 1) / polymer according to (a)

[0043] In some preferred embodiments of the aqueous dispersion, the ethylenically unsaturated monomer (a.1), from which the polymer according to (a) is obtained or obtainable, is selected from the group consisting of C1-C20 (meth)acrylate, styrene, vinyltoluene, hydroxy-functional C1- C20 (meth)acrylate, (meth)acrylate derived from alkoxylated alcohol, multifunctional (methacrylate, and mixtures of two or more thereof. A multifunctional (meth)acrylate is preferably a di or tri functional (meth)acrylate suitable as crosslinker, such as, for example, trimethylolpropantriacry- late.

[0044] In some preferred embodiments of the aqueous dispersion, the polymer according to (a) comprises at least one polymer selected from the group consisting of poly(meth)acrylate, styreneacrylate copolymer, vinylester polymer, vinylester copolymer, copolymer of ethylene and vinylacetate, copolymer of vinylacetate and acrylate, polybutadiene, copolymer of styrene and butadiene, polyester, copolyester, polyurethane, and mixtures of two or more thereof.

[0045] In some preferred embodiments of the aqueous dispersion, the polymer according to (a) comprises at least one polymer selected from the group consisting of stearyl methacrylate, methyl methacrylate, methacrylic acid, butanediol diacrylate, isobutylmethacrylate, vinyl toluene, cyclohexylmethacrylate, 2-hydroxyethylmethacrylate, and mixtures of two or more thereof.

[0046] In some preferred embodiments of the aqueous dispersion, the polymer according to (a) comprises at least one polyacrylate copolymer obtained or obtainable from a mixture of at least two ethylenically unsaturated monomers (a.1), wherein > 50 % by weight of the mixture are two or more (meth)acrylate monomers, based on the total weight of the mixture being 100 % by weight. Preferably, for obtaining the polymer according to (a), the pH value of the aqueous dispersion is maintained above 5, more preferably by use of a suitable buffer, for example, sodium hydrogen carbonate.

[0047] Surfactant

[0048] In some preferred embodiments, the aqueous dispersion further comprises (c) at least one surfactant.

[0049] In some preferred embodiments of the aqueous dispersion, the at least one surfactant according to (c) is selected from the group consisting of non-ionic surfactant, cationic surfactant, anionic surfactant and mixtures of two or more thereof, preferably from the group consisting of nonionic surfactant, anionic surfactant and mixture of non-ionic surfactant and anionic surfactant, more preferably from the group consisting of alkali and ammonium salt of C12-C16 alkylsulfonic acid, dialkyl ester of succinic acid, monoalkyl ester of succinic acid, or sulfuric acid halfester of ethoxylated alkanole, C12-C18 alkylgylcoside, aliphatic or araliphatic compound, preferably ethoxylated phenol (mon, di, tri) with an ethoxylation degree of 3 to 50 and alkyl groups in the range from C4-C9, ethoxylated long chain alcohol, polyethyleneoxide / polypropyleneoxide block copolymer and mixtures of two or more thereof.

[0050] In some preferred embodiments of the aqueous dispersion, the at least one surfactant according to (c) is present in an amount in the range of from 0.01 to 50 % by weight, based on the total weight of all ethylenically unsaturated monomers (a.1) being 100 % by weight.

[0051] 2ndaspect - Method for preparing an aqueous dispersion comprising polymer particles

[0052] In a second aspect, the invention relates to a method for preparing an aqueous dispersion comprising polymer particles, the polymer particles comprising

[0053] (a) a polymer carrier obtained or obtainable from at least one ethylenically unsaturated monomer (a.1); (b) a compound comprising at least one epoxy group;

[0054] (c) optionally at least one surfactant; the method comprising radical polymerization of the at least one ethylenically unsaturated monomer (a.1) within an aqueous emulsion comprising the compound comprising at least one epoxy group (b), the at least one ethylenically unsaturated monomer and optionally the at least one surfactant (c).

[0055] All details, embodiments and preferred embodiments described above in the second related to the first aspect of the invention also apply for the second aspect of the invention.

[0056] In some preferred embodiments, the aqueous emulsion comprises the compound comprising at least one epoxy group (b), the at least one ethylenically unsaturated monomer (a.1) and optionally the at least one surfactant (c) in the form of droplets, preferably droplets, wherein at least 95 % of the droplets have a diameter of < 1000 nm, determined by DLS.

[0057] During the radical polymerization, the polymer carrier is formed from the at least one ethylenically unsaturated monomer (a.1). However, it has to be noted that no covalent bound is formed during said radical polymerization between the polymer carrier of (a) and the compound comprising at least one epoxy group of (b).

[0058] In some preferred embodiments of the method for preparing an aqueous dispersion comprising polymer particles, wherein the polymer particles comprises

[0059] (a) a polymer carrier obtained or obtainable from at least one ethylenically unsaturated monomer (a.1);

[0060] (b) a compound comprising at least one epoxy group;

[0061] (c) optionally at least one surfactant; the method comprises radical polymerization of the at least one ethylenically unsaturated monomer (a.1) within an aqueous emulsion comprising the compound comprising at least one epoxy group (b), the at least one ethylenically unsaturated monomer (a.1) and optionally the at least one surfactant (c), without formation of a covalent bond between polymer carrier of (a) and compound comprising at least one epoxy group of (b).

[0062] (Volatile) Organic solvents

[0063] Preferably, the method is carried out in the absence of volatile organic solvents. Preferably, less than 1000 weight-ppm of the aqueous emulsion are one or more volatile organic solvent(s). “Volatile” means that the organic solvent has at 1013 hPa a boiling point of less than 100 °C, preferably of less than 90 °C.

[0064] Thus, in some preferred embodiments of the method for preparing an aqueous dispersion comprising polymer particles, wherein the polymer particles comprises

[0065] (a) a polymer carrier obtained or obtainable from at least one ethylenically unsaturated monomer (a.1);

[0066] (b) a compound comprising at least one epoxy group;

[0067] (c) optionally at least one surfactant; the method comprises radical polymerization of the at least one ethylenically unsaturated monomer (a.1) within an aqueous emulsion comprising the compound comprising at least one epoxy group (b), the at least one ethylenically unsaturated monomer (a.1) and optionally the at least one surfactant (c), without formation of a covalent bond between polymer carrier of (a) and compound comprising at least one epoxy group of (b); wherein the aqueous emulsion comprises less than 1000 weight-ppm of one or more volatile organic solvent(s).

[0068] More preferably less than 500 weight-ppm, more preferably less than 100 weight-ppm, more preferably less than 10 weight-ppm, more preferably less than 5 weight-ppm, of the aqueous emulsion are one or more volatile organic solvent(s), wherein the total weight of the aqueous emulsion are always 100 weight-%.

[0069] More preferably, the aqueous emulsion is free of organic solvents. Preferably, less than 1000 weight-ppm of the aqueous emulsion are one or more organic solvent(s).

[0070] Thus, in some preferred embodiments of the method for preparing an aqueous dispersion comprising polymer particles, wherein the polymer particles comprises

[0071] (a) a polymer carrier obtained or obtainable from at least one ethylenically unsaturated monomer (a.1);

[0072] (b) a compound comprising at least one epoxy group;

[0073] (c) optionally at least one surfactant; the method comprises radical polymerization of the at least one ethylenically unsaturated monomer (a.1) within an aqueous emulsion comprising the compound comprising at least one epoxy group (b), the at least one ethylenically unsaturated monomer (a.1) and optionally the at least one surfactant (c), without formation of a covalent bond between polymer carrier of (a) and compound comprising at least one epoxy group of (b); wherein the aqueous emulsion comprises less than 1000 weight-ppm of one or more organic solvent(s). More preferably less than 500 weight-ppm, more preferably less than 100 weight-ppm, more preferably less than 10 weight-ppm, more preferably less than 5 weight-ppm, of the aqueous emulsion are one or more organic solvent(s), wherein the total weight of the aqueous emulsion are always 100 weight-%.

[0074] More preferably, the one or more organic solvent(s) are selected from the group consisting of methyl acetate, ethyl acetate, n-propyl acetate, isobutyl acetate, n-butyl alcohol, chloroform, carbon tetrachloride, ethylene chloride, sec-butyl acetate, cyclohexanone, n-amyl alcohol, diethyl ether, methyl-n-propyl ketone, benzene, toluene, xylene, butoxyethyl acetate, acetone, methyl ethyl ketone, ethyl alcohol, methyl alcohol, isopropyl alcohol, n-propyl alcohol, tetrahydrofuran, ethylene glycol monomethyl ether, N-methylpyrrolidone, dimethylformamide, dimethyl sulfoxide, butyldiethoxy alcohol, dipropylene glycol methyl ether, and mixtures of two or more thereof.

[0075] Thus, the aqueous emulsion, aside from the components mentioned herein above, essentially consists of water. Preferably, at least 99 weight-%, preferably at least 99.5 weight-%, more preferably at least 99.5 weight-%, of the aqueous emulsion consist of the at least one ethylenically unsaturated monomer (a.1), compound comprising at least one epoxy group of (b), non-volatile organic solvent, and water, and optionally the at least one surfactant (c), wherein the total weight of the aqueous emulsion are always 100 weight-%.

[0076] 3rdaspect - Product-by-process

[0077] A third aspect of the invention relates to an aqueous dispersion comprising polymer particles, the polymer particles comprising

[0078] (a) a polymer carrier obtained or obtainable from at least one ethylenically unsaturated monomer (a.1);

[0079] (b) a compound comprising at least one epoxy group,

[0080] (c) optionally at least one surfactant, obtained or obtainable from the method of the second aspect.

[0081] All details, embodiments and preferred embodiments described above in the second related to the first aspect and / or the second aspect of the invention also apply for the third aspect of the invention.

[0082] 4thaspect - Use In a fourth aspect, the invention relates to the use of an aqueous dispersion comprising polymer particles, the polymer particles comprising (a) a polymer carrier obtained or obtainable from at least one ethylenically unsaturated monomer (a.1), (b) a compound comprising at least one epoxy group, and (c) optionally at least one surfactant, as additive for a water borne coating.

[0083] All details, embodiments and preferred embodiments described above in the second related to the first aspect and / or the second aspect and / or the third aspect of the invention also apply for the fourth aspect of the invention.

[0084] In some preferred embodiments the aqueous dispersion is used as additive for improving abrasion resistance of a water borne coating, preferably for improving wet-scrub resistance of a water borne coating. Preferably, the water borne coating is a paint or an ink, more preferably a paint, more preferably an interior wall paint and / or an interior architectural paint.

[0085] In some preferred embodiments, the invention also relates to a method for preparing an addi- tivated water borne coating, the method comprising:

[0086] (I) Providing an aqueous dispersion comprising polymer particles, the polymer particles comprising (a) a polymer carrier obtained or obtainable from at least one ethylenically unsaturated monomer (a.1), (b) a compound comprising at least one epoxy group, and (c) optionally at least one surfactant; and providing a water borne coating;

[0087] (II) Adding the aqueous dispersion comprising polymer particles provided in (I) to the water borne coating provided in (I); thereby obtaining an additivated water-borne coating.

[0088] Also regarding the method for preparing an additivated water borne coating, it applies that the water borne coating is preferably a paint or an ink, more preferably a paint, more preferably an interior wall paint and / or an interior architectural paint.

[0089] Preferably, the polymer carrier of (a) and the compound comprising at least one epoxy group are not covalently bounded to each other.

[0090] Preferably, the aqueous dispersion comprises less than 1000 weight-ppm, more preferably less than 500 weight-ppm, more preferably less than 100 weight-ppm, more preferably less than 10 weight-ppm, more preferably less than 5 weight-ppm, of the aqueous dispersion are one or more volatile organic solvent(s), wherein the total weight of the aqueous dispersion are 100 weight-% Preferably, the aqueous dispersion comprises less than 1000 weight-ppm, more preferably less than 500 weight-ppm, more preferably less than 100 weight-ppm, more preferably less than 10 weight-ppm, more preferably less than 5 weight-ppm, of the aqueous dispersion are one or more organic solvent(s), wherein the total weight of the aqueous dispersion are 100 weight-%

[0091] Preferably, the one or more organic solvent(s) are selected from the group consisting of methyl acetate, ethyl acetate, n-propyl acetate, isobutyl acetate, n-butyl alcohol, chloroform, carbon tetrachloride, ethylene chloride, sec-butyl acetate, cyclohexanone, n-amyl alcohol, diethyl ether, methyl-n-propyl ketone, benzene, toluene, xylene, butoxyethyl acetate, acetone, methyl ethyl ketone, ethyl alcohol, methyl alcohol, isopropyl alcohol, n-propyl alcohol, tetrahydrofuran, ethylene glycol monomethyl ether, N-methylpyrrolidone, dimethylformamide, dimethyl sulfoxide, butyldiethoxy alcohol, dipropylene glycol methyl ether, and mixtures of two or more thereof.

[0092] Thus, the aqueous dispersion, aside from the components mentioned herein above, essentially consists of water. Preferably, at least 99 weight-%, preferably at least 99.5 weight-%, more preferably at least 99.5 weight-%, of the aqueous dispersion consist of polymer carrier of (a), compound comprising at least one epoxy group of (b), a non-volatile organic solvent, at least one surfactant, and water, wherein the total weight of the aqueous dispersion are always 100 weight-%.

[0093] 5thaspect - Water-based paint composition

[0094] In a fifth aspect, the invention relates to a water-based paint composition, obtained or obtainable by adding an aqueous dispersion comprising polymer particles according to the first aspect to a water-based paint.

[0095] All details, embodiments and preferred embodiments described above in the second related to the first aspect and / or the second aspect and / or the third aspect and / or the fourth aspect of the invention also apply for the fifth aspect of the invention.

[0096] Preferably, the polymer carrier of (a) and the compound of (b) are not covalently bonded to each other.

[0097] Preferably, the water-based paint composition comprises less than 1000 weight-ppm, preferably less than 500 ppm, more preferably less than 100 weight-ppm, more preferably less than 10 weight-ppm, more preferably less than 5 weight-ppm of one or more volatile organic solvent(s). Preferably, the water-based paint composition comprises less than 1000 weight-ppm, preferably less than 500 ppm, more preferably less than 100 weight-ppm, more preferably less than 10 weight-ppm, more preferably less than 5 weight-ppm of one or more organic solvent(s).

[0098] Preferably, the water-based paint composition comprises less than the one or more organic solvents) are selected from the group consisting of methyl acetate, ethyl acetate, n-propyl acetate, isobutyl acetate, n-butyl alcohol, chloroform, carbon tetrachloride, ethylene chloride, sec-butyl acetate, cyclohexanone, n-amyl alcohol, diethyl ether, methyl-n-propyl ketone, benzene, toluene, xylene, butoxyethyl acetate, acetone, methyl ethyl ketone, ethyl alcohol, methyl alcohol, isopropyl alcohol, n-propyl alcohol, tetra hydrofuran, ethylene glycol monomethyl ether, N- methylpyrrolidone, dimethylformamide, dimethyl sulfoxide, butyldiethoxy alcohol, dipropylene glycol methyl ether, and mixtures of two or more thereof.

[0099] 6thaspect - water-based paint composition comprising polymer particles

[0100] In a sixth aspect, the invention relates to a water-based paint composition comprising polymer particles, the polymer particles comprising (a) a polymer carrier obtained or obtainable from at least one ethylenically unsaturated monomer (a.1), (b) a compound comprising at least one epoxy group, and (c) optionally at least one surfactant.

[0101] All details, embodiments and preferred embodiments described above in the second related to the first aspect and / or the second aspect and / or the third aspect and / or the fourth aspect and / or the fifth aspect of the invention also apply for the sixth aspect of the invention.

[0102] In some preferred embodiments, the water-based paint composition further comprises at least one binder, preferably a binder selected from the group consisting of synthetic resin, natural resin or mixture of synthetic and natural resin, preferably selected from the group consisting of alkyd, acrylic polymer, styrene acrylic polymer, vinyl-acrylic polymer, vinyl acetate / ethylene polymer, polyurethane, polyester, polyester polyurethane, melamine resin, polyepoxide, silane, siloxane, oil or mixtures of two or more thereof, more preferably from the group consisting of styrene acrylic polymer, acrylic polymer, polyester polyurethane and mixtures of two or three thereof, preferably in an amount in the range of from 10 to 80 %by weight, more preferably in the range of from 20 to 70 % by weight, based on the total weight of the water-based paint composition being 100 % by weight. In some preferred embodiments, the water-based paint composition further comprises at least one filler, preferably a filler selected from the group consisting of talc, diatomite, mica, aluminum silicate, calcium carbonate and mixtures of two or more thereof, preferably in an amount in the range of from 1 to 30 %by weight, more preferably in the range of from 5 to 20 % by weight, based on the total weight of the water-based paint composition being 100 % by weight.

[0103] In some preferred embodiments, the water-based paint composition comprises at least one colorant in an amount in the range of from 0.1 to 25 % by weight, preferably in the range of from 5 to 10 % by weight, based on the total weight of the water-based paint composition being 100 % by weight. A “colorant” is a substance that cause the change of color impression of a material, i.e. , which absorb wavelength intervals of visible light (400 to 780 nm) and / or which scatters light. In some preferred embodiments of the water-based paint composition, the colorant is a dye and / or a pigment, more preferably and organic and / or inorganic pigment.

[0104] In some preferred embodiments, the water-based paint composition further comprises polyacrylate type rheology modifiers and / or carboxylic acid-based dispersants. Preferably, the polyacrylate type rheology modifiers comprise (H)ASE type thickeners. Preferably, the carboxylic acidbased dispersants are selected from the group of polyacrylic acid, polyacrylic acid copolymer, copolymer based on maleic anhydride copolymer, and mixtures of two or more thereof.

[0105] In some preferred embodiments, the water-based paint composition further comprises the compound comprising at least one epoxy group in an amount in the range of from 0.01 to 1 % by weight, preferably in the range of from 0.05 to 0.5 weight-%, based on the total weight of the water-based paint composition being 100 % by weight.

[0106] In some preferred embodiments, the water-based paint composition comprising water in an amount in the range of from 5 to 60 % by weight, preferably in the range of from 20 to 30 % by weight, based on the total weight of the water-based paint composition being 100 % by weight.

[0107] The water-based paint composition comprises the polymer particles and may, aside from the above-mentioned binders, fillers, colorants, rheology modifiers, dispersants, and thickeners further comprise typical additives in dissolved or suspended or emulsified form. Examples of such additives are defoaming agents, film formation agents, substrate wetting agents, surface levelling agents, slip and anti-blocking agents, biocides, UV absorbers, adhesion promoters and mixtures of two or more thereof.

[0108] 7thaspect - Coating A seventh aspect of the invention relates to a coating, obtained or obtainable from application of a water-based paint composition according to the third aspect or according to the fifth aspect to a surface, preferably to a surface of a substrate.

[0109] All details, embodiments and preferred embodiments described above in the second related to the first aspect and / or the second aspect and / or the third aspect and / or the fourth aspect and / or the fifth aspect and / or the sixth aspect of the invention also apply for the seventh aspect of the invention.

[0110] In some preferred embodiments of the coating, the surface is a wall and / or a ceiling of a building or a partial area thereof, more preferably an interior wall and / or ceiling of a building or a partial area thereof.

[0111] As indicated above in the first section related to the aqueous dispersion comprising polymer particles, the additive, i.e. , the aqueous dispersion comprising polymer particles, comprises aqueous polymer colloid particles containing therein epoxy compounds, wherein the polymer acts as carrier to which the epoxy compound is “attached and / or by which the epoxy compound is at least partially surrounded”. The polymer particles are prepared or preparable, for example, via mini-emulsion polymerization technology, thereby obtaining small polymer colloid particles. In this context, the terms “attached and / or at least partially surrounded” relate to the fact, that the water insoluble epoxy compound cannot be expected to migrate out of the polymer particle, if the surrounding water phase is present. Based on the unexpected findings, and without being bound to any theory, it is believed that the mode of action of the additive for improving paint film resistance properties is, that the epoxy compound can migrate out of the polymer colloid particles, when film formation of the water-based paint composition has taken place and when the continuous water phase has essentially disappeared. In the remaining substantially dry paint film, the epoxy compound is believed to react with CChH-groups and / or with OH-groups, preferably at least with CChH-groups, which are abundant and always present in the paint film from various common components like the binder polymers, and / or additives like dispersants and / or like rheology modifiers. Especially the fact, that all common waterborne paint binder polymers contain CChH-functionalities, as well as many common paint additives like dispersants or rheology modifiers, is believed to render this additive concept very useful and universal, because it does not require extra chemical functionalization of common paint formulation components like waterborne binders or additives. The present invention is further illustrated by the following set of embodiments and combinations of embodiments resulting from the dependencies and back-references as indicated. In particular, it is noted that in each instance where a range of embodiments is mentioned, for example in the context of a term such as "The aqueous dispersion of any one of embodiments 1 to 4", every embodiment in this range is meant to be explicitly disclosed for the skilled person, i.e. the wording of this term is to be understood by the skilled person as being synonymous to "The aqueous dispersion of any one of embodiments 1 , 2, 3 and 4". Further, it is explicitly noted that the following set of embodiments represents a suitably structured part of the general description directed to preferred aspects of the present invention, and, thus, suitably supports, but does not represent the claims of the present invention.

[0112] 1 . An aqueous dispersion comprising polymer particles, the polymer particles comprising

[0113] (a) a polymer carrier obtained or obtainable from at least one ethylenically unsaturated monomer (a.1);

[0114] (b) a compound comprising at least one epoxy group.

[0115] 2. The aqueous dispersion of embodiment 1 , wherein the aqueous dispersion comprises polymer particles, the polymer particles comprising

[0116] (a) a polymer carrier obtained or obtainable from at least one ethylenically unsaturated monomer (a.1);

[0117] (b) a compound comprising at least one epoxy group; wherein the polymer carrier of (a) and the compound of (b) are not covalently bonded to each other.

[0118] 3. The aqueous dispersion of embodiment 1 or 2, wherein the aqueous dispersion comprises polymer particles, the polymer particles comprising

[0119] (a) a polymer carrier obtained or obtainable from at least one ethylenically unsaturated monomer (a.1);

[0120] (b) a compound comprising at least one epoxy group; wherein the polymer carrier of (a) and the compound of (b) are not covalently bonded to each other; and wherein the aqueous dispersion comprises less than 1000 weight-ppm of one or more volatile organic solvent(s).

[0121] 4. The aqueous dispersion of embodiment 3, wherein less than 500 weight-ppm, preferably less than 100 weight-ppm, more preferably less than 10 weight-ppm, more preferably less than 5 weight-ppm, of the aqueous dispersion are one or more volatile organic solvent(s), wherein the total weight of the aqueous dispersion are 100 weight-%. The aqueous dispersion of any one of embodiments 1 to 4, wherein the aqueous dispersion comprises polymer particles, the polymer particles comprising

[0122] (a) a polymer carrier obtained or obtainable from at least one ethylenically unsaturated monomer (a.1);

[0123] (b) a compound comprising at least one epoxy group; wherein the polymer carrier of (a) and the compound of (b) are not covalently bonded to each other; and wherein the aqueous dispersion comprises less than 1000 weight-ppm of one or more organic solvent(s). The aqueous dispersion of embodiment 5, wherein less than 500 weight-ppm, preferably less than 100 weight-ppm, more preferably less than 10 weight-ppm, more preferably less than 5 weight-ppm, of the aqueous dispersion are one or more organic solvent(s), wherein the total weight of the aqueous dispersion are 100 weight-%. The aqueous dispersion of embodiment 5 or 6, wherein the one or more organic solvents) are selected from the group consisting of methyl acetate, ethyl acetate, n-propyl acetate, isobutyl acetate, n-butyl alcohol, chloroform, carbon tetrachloride, ethylene chloride, sec-butyl acetate, cyclohexanone, n-amyl alcohol, diethyl ether, methyl-n-propyl ketone, benzene, toluene, xylene, butoxyethyl acetate, acetone, methyl ethyl ketone, ethyl alcohol, methyl alcohol, isopropyl alcohol, n-propyl alcohol, tetrahydrofuran, ethylene glycol monomethyl ether, N-methylpyrrolidone, dimethylformamide, dimethyl sulfoxide, butyldiethoxy alcohol, dipropylene glycol methyl ether, and mixtures of two or more thereof. The aqueous dispersion of any one of embodiments 1 to 7, wherein > 95 % of the polymer particles have a diameter of < 1000 nm, preferably in the range of from 20 to 1000 nm, more preferably in the range of from 20 to 500 nm, more preferably in the range of from 30 to 300 nm, determined by dynamic light scattering (DLS). The aqueous dispersion of any one of embodiments 1 to 8, wherein the compound containing at least one epoxy group according to (b) is present in an amount in the range of from 10 to 90 % by weight, preferably in the range of from 25 to 75 % by weight, more preferably in the range of from 40 to 60 % by weight based on the total weight of the polymer particle being 100 % by weight. The aqueous dispersion of any one of embodiments 1 to 9, wherein the compound containing at least one epoxy group according to (b) is selected from mono-functional epoxy compound, multifunctional epoxy compound, epoxy-functional oligomer, epoxy-functional polymer, wherein an epoxy-functional polymer is preferably selected from the group consisting of epoxy-functional polysiloxane, epoxy-functional polyacrylate, epoxy-functional polybutadiene and mixtures of two or more thereof. The aqueous dispersion of any one of embodiments 1 to 10, wherein the compound containing at least one epoxy group according to (b) is selected from multifunctional epoxy compound, epoxy-functional oligomer, and mixtures of these two, each having an epoxyfunctionality > 1 , more preferably > 2. The aqueous dispersion of any one of embodiments 1 to 11 , wherein the compound containing at least one epoxy group according to (b) is selected from the group consisting of glycidylether of aliphatic alcohol, glycidylether of aromatic alcohol, glycidylether of multifunctional aliphatic alcohol, glycidylether of aromatic alcohol, wherein the aliphatic alcohol, aromatic alcohol, multifunctional aliphatic alcohol and aromatic alcohol each have more than 6 carbon atoms, diglycidylether of difunctional aliphatic cyclic alcohol, diglycidylether of difunctional aliphatic branched alcohol, diglycidylether of difunctional aliphatic linear alcohol, glycidylether of glyceride, glycidyl ether of partial glyceride, Bisphenol-A-diglyc- idylether, oligomer composed of Bisphenol-A-diglycidylether, Bisphenol-F-diglycidylether, oligomer composed of Bisphenol-F-diglycidylether, polysiloxane-based structure with pending glycidyl groups, modified or unmodified novolac epoxy resin (phenol and cresol types), tetraglycidyl ether of tetraphenol ethane, glycidyl ether of mono- or polyfunctional alkoxylate, (meth)acrylic / styrenic copolymers with epoxy functionality, glycidylester of mono or polyfunctional carboxylic acid, (acrylic) (co)polymer / oligomer based on glyc- idyl(meth)acrylate as monomer, and mixtures of two or more thereof. The aqueous dispersion of any one of embodiments 1 to 12, wherein the compound containing at least one epoxy group according to (b) is selected from the group consisting of bisphenol A diglycidyl ether, dodecyl / tetradecyl-glycidylether, branched C13-C15-glyc- idylether, glycidyl-hexadecylether, (epoxycyclohexylethyl)methylsiloxane-dimethylsiloxane copolymer, linear polydimethylsiloxane with terminal epoxy groups, linear comb-type poylsiloxane with pending glycidyl groups having a functional group equivalent weight in the range of from 300 to 4000 g / mol, epoxidized soybean oil, diglycidyl ether based on cyclohexanedimethanol, monoglycidyl ether based on C13-C15-alkohols, bisphenol F-resin (phenol-formaldehyde polymer glycidyl ether), bisphenol A-resin having a viscosity in the range of from 5 to 20 Pas at 25 °C, diglycidyl ether epoxy resin, polyglycidyl ether of an alkenyl phenol formaldehyde novolac resin, 4,4'-Methylen-bis-(N, N-diglycidylanilin), tris(4- hydroxyphenyl)methane triglycidylether, poly(meth)acrylate with epoxy-functionality, copolymer based on (meth)acrylate and (methyl)styrene with epoxy-functionality, and mixtures of two or more thereof. The aqueous dispersion of any one of embodiments 1 to 13, wherein the compound containing at least one epoxy group according to (b) is selected from the group consisting of epoxide, which is derived from a mono or multi unsaturated nonpolar compound by epoxidation of the corresponding double bond(s), preferably selected from the group consisting of unsaturated non-polar compound of natural origin, the unsaturated non-polar compound of natural origin preferably being selected from the group consisting of sunflower oil, tall oil, soy-bean oil, castor oil, linseed oil, palm oil, rapeseed oil, cashew nutshell liquid, and mixtures of two or more thereof, cardanol, natural rubber, sucrose soyate, terpene based compound, and mixtures of two or more thereof. The aqueous dispersion of any one of embodiments 1 to 14, wherein the ethylenically unsaturated monomer (a.1), from which the polymer according to (a) is obtained or obtainable, is selected from the group consisting of C1-C20 (meth)acrylate, styrene, vinyltoluene, hydroxy-functional C1-C20 (meth)acrylate, (meth)acrylate derived from alkoxylated alcohol, multifunctional (meth)acrylate, and mixtures of two or more thereof. The aqueous dispersion of any one of embodiments 1 to 15, wherein the polymer according to (a) comprises at least one polymer selected from the group consisting of poly(meth)acrylate, styrene-acrylate copolymer, vinylester polymer, vinylester copolymer, copolymer of ethylene and vinylacetate, copolymer of vinylacetate and acrylate, polybutadiene, copolymer of styrene and butadiene, polyester, copolyester, polyurethane, and mixtures of two or more thereof. The aqueous dispersion of any one of embodiments 1 to 16, wherein the polymer according to (a) comprises at least one polymer selected from the group consisting of stearyl methacrylate, methyl methacrylate, methacrylic acid, butanediol diacrylate, isobutylmethacrylate, vinyl toluene, cyclohexylmethacrylate, 2-hydroxyethylmethacrylate, and mixtures of two or more thereof. 18. The aqueous dispersion of any one of embodiments 1 to 17, wherein the polymer according to (a) comprises at least one polyacrylate copolymer obtained or obtainable from a mixture of at least two ethylenically unsaturated monomers (a.1), wherein > 50 % by weight of the mixture are two or more (meth)acrylate monomers, based on the total weight of the mixture being 100 % by weight.

[0124] 19. The aqueous dispersion of any one of embodiments 1 to 18, further comprising (c) at least one surfactant.

[0125] 20. The aqueous dispersion of embodiment 19, wherein the at least one surfactant according to (c) is selected from the group consisting of non-ionic surfactant, cationic surfactant, anionic surfactant and mixtures of two or more thereof, preferably from the group consisting of non-ionic surfactant, anionic surfactant and mixture of non-ionic surfactant and anionic surfactant, more preferably from the group consisting of alkali and ammonium salt of C12- C16 alkylsulfonic acid, dialkyl ester of succinic acid, monoalkyl ester of succinic acid, or sulfuric acid halfester of ethoxylated alkanole, C12-C18 alkylgylcoside, aliphatic or arali- phatic compound, preferably ethoxylated phenol (mono, di, tri) with an ethoxylation degree of 3 to 50 and alkyl groups in the range from C4-C9, ethoxylated long chain alcohol, poly- ethyleneoxide / polypropyleneoxide block copolymer and mixtures of two or more thereof.

[0126] 21. The aqueous dispersion of embodiment 19 or 20, wherein the at least one surfactant according to (c) is present in an amount in the range of from 0.01 to 50 % by weight, based on the total weight of all ethylenically unsaturated monomers (a.1) being 100 % by weight.

[0127] 22. A method for preparing an aqueous dispersion comprising polymer particles, the polymer particles comprising

[0128] (a) a polymer carrier obtained or obtainable from at least one ethylenically unsaturated monomer (a.1);

[0129] (b) a compound comprising at least one epoxy group;

[0130] (c) optionally at least one surfactant; the method comprising radical polymerization of the at least one ethylenically unsaturated monomer (a.1) within an aqueous emulsion comprising the compound comprising at least one epoxy group (b), the at least one ethylenically unsaturated monomer (a.1) and optionally the at least one surfactant (c).

[0131] 23. The method of embodiment 22, comprising radical polymerization of the at least one ethylenically unsaturated monomer within an aqueous emulsion comprising the compound comprising at least one epoxy group (b), the at least one ethylenically unsaturated monomer (a.1) and optionally the at least one surfactant (c), without formation of a covalent bond between polymer carrier of (a) and compound comprising at least one epoxy group of (b). The method of embodiment 22 or 23, wherein the aqueous emulsion comprises less than 1000 weight-ppm of one or more volatile organic solvent(s). The method of embodiment 24, wherein less than 500 weight-ppm, preferably less than 100 weight-ppm, more preferably less than 10 weight-ppm, more preferably less than 5 weight-ppm, of the aqueous emulsion are one or more volatile organic solvent(s), wherein the total weight of the aqueous emulsion are 100 weight-%. The method of any one of embodiments 22 to 25, wherein the aqueous emulsion comprises less than 1000 weight-ppm of one or more organic solvent(s). The method of embodiment 26, wherein less than 500 weight-ppm, preferably less than 100 weight-ppm, more preferably less than 10 weight-ppm, more preferably less than 5 weight-ppm, of the aqueous emulsion are one or more organic solvent(s), wherein the total weight of the aqueous emulsion are 100 weight-%. The method of any one of embodiments 22 to 27, wherein the one or more organic solvents) are selected from the group consisting of methyl acetate, ethyl acetate, n-propyl acetate, isobutyl acetate, n-butyl alcohol, chloroform, carbon tetrachloride, ethylene chloride, sec-butyl acetate, cyclohexanone, n-amyl alcohol, diethyl ether, methyl-n-propyl ketone, benzene, toluene, xylene, butoxyethyl acetate, acetone, methyl ethyl ketone, ethyl alcohol, methyl alcohol, isopropyl alcohol, n-propyl alcohol, tetrahydrofuran, ethylene glycol monomethyl ether, N-methylpyrrolidone, dimethylformamide, dimethyl sulfoxide, butyldiethoxy alcohol, dipropylene glycol methyl ether, and mixtures of two or more thereof. The method of any one of embodiments 22 to 28, wherein the aqueous emulsion comprises the compound comprising at least one epoxy group (b), the at least one ethylenically unsaturated monomer (a.1) and optionally the at least one surfactant (c) in the form of droplets, preferably droplets, wherein at least 95 % of the droplets have a diameter of < 1000 nm, determined by DLS. An aqueous dispersion comprising polymer particles, the polymer particles comprising (a) a polymer carrier obtained or obtainable from at least one ethylenically unsaturated monomer (a.1);

[0132] (b) a compound comprising at least one epoxy group,

[0133] (c) optionally at least one surfactant, obtained or obtainable from the method of any one of embodiments 22 to 29.

[0134] 31. Use of an aqueous dispersion comprising polymer particles, the polymer particles comprising (a) a polymer carrier obtained or obtainable from at least one ethylenically unsaturated monomer (a.1), (b) a compound comprising at least one epoxy group, and (c) optionally at least one surfactant, as additive for a water borne coating.

[0135] 32. The use of embodiment 31 , wherein the polymer carrier of (a) and the compound comprising at least one epoxy group are not covalently bounded to each other.

[0136] 33. The use of embodiment 31 or 32, wherein the aqueous dispersion comprises less than 1000 weight-ppm, preferably less than 500 weight-ppm, more preferably less than 100 weight-ppm, more preferably less than 10 weight-ppm, more preferably less than 5 weight-ppm, of the aqueous dispersion are one or more volatile organic solvent(s), wherein the total weight of the aqueous dispersion are 100 weight-%

[0137] 34. The use of any one of embodiments 31 to 33, wherein the aqueous dispersion comprises less than 1000 weight-ppm, preferably less than 500 weight-ppm, more preferably less than 100 weight-ppm, more preferably less than 10 weight-ppm, more preferably less than 5 weight-ppm, of the aqueous dispersion are one or more organic solvent(s), wherein the total weight of the aqueous dispersion are 100 weight-%

[0138] 35. The use of any one of embodiments 31 to 34, wherein the aqueous dispersion is used as additive for improving abrasion resistance of a water borne coating, preferably for improving wet-scrub resistance of a water borne coating.

[0139] 35. The use of any one of embodiments 31 to 34, wherein the water borne coating is a paint or an ink, preferably a paint, more preferably an interior wall paint and / or an interior architectural paint.

[0140] 37. A water-based paint composition obtained or obtainable by adding an aqueous dispersion comprising polymer particles according to any one of embodiments 1 to 21 to a waterbased paint. 38. A water-based paint composition comprising polymer particles, the polymer particles comprising (a) a polymer carrier obtained or obtainable from at least one ethylenically unsaturated monomer (a.1), (b) a compound comprising at least one epoxy group, and (c) optionally at least one surfactant.

[0141] 39. The water-based paint composition of embodiment 38, wherein the polymer carrier of (a) and the compound of (b) are not covalently bonded to each other.

[0142] 40. The water-based paint composition of embodiment 38 or 39 comprising less than 1000 weight-ppm, preferably less than 500 weight-ppm, more preferably less than 100 weight- ppm, more preferably less than 10 weight-ppm, more preferably less than 5 weight-ppm of one or more volatile organic solvent(s).

[0143] 41 . The water-based paint composition of any one of embodiments 38 to 40 comprising less than 1000 weight-ppm, preferably less than 500 weight-ppm, more preferably less than 100 weight-ppm, more preferably less than 10 weight-ppm, more preferably less than 5 weight-ppm of one or more organic solvent(s).

[0144] 42. The water-based paint composition of embodiment 41 , wherein the one or more organic solvent(s) are selected from the group consisting of methyl acetate, ethyl acetate, n-propyl acetate, isobutyl acetate, n-butyl alcohol, chloroform, carbon tetrachloride, ethylene chloride, sec-butyl acetate, cyclohexanone, n-amyl alcohol, diethyl ether, methyl-n-propyl ketone, benzene, toluene, xylene, butoxyethyl acetate, acetone, methyl ethyl ketone, ethyl alcohol, methyl alcohol, isopropyl alcohol, n-propyl alcohol, tetrahydrofuran, ethylene glycol monomethyl ether, N-methylpyrrolidone, dimethylformamide, dimethyl sulfoxide, butyldiethoxy alcohol, dipropylene glycol methyl ether, and mixtures of two or more thereof.

[0145] 43. The water-based paint composition of any one of embodiments 38 to 42, further comprising at least one binder, preferably a binder selected from the group consisting of synthetic resin, natural resin or mixture of synthetic and natural resin, preferably selected from the group consisting of alkyd, acrylic polymer, styrene acrylic polymer, vinyl-acrylic polymer, vinyl acetate / ethylene polymer, polyurethane, polyester, polyester polyurethane, melamine resin, polyepoxide, silane, siloxane, oil or mixtures of two or more thereof, more preferably from the group consisting of styrene acrylic polymer, acrylic polymer, polyester polyurethane and mixtures of two or three thereof, preferably in an amount in the range of from 10 to 80 %by weight, more preferably in the range of from 20 to 70 % by weight, based on the total weight of the water-based paint composition being 100 % by weight. The water-based paint composition of any one of embodiments 38 to 43, further comprising at least one filler, preferably a filler selected from the group consisting of talc, diatomite, mica, aluminum silicate, calcium carbonate and mixtures of two or more thereof, preferably in an amount in the range of from 1 to 30 %by weight, more preferably in the range of from 5 to 20 % by weight, based on the total weight of the water-based paint composition being 100 % by weight. The water-based paint composition of any one of embodiments 38 to 44, comprising at least one colorant in an amount in the range of from 0.1 to 25 %by weight, preferably in the range of from 5 to 10 % by weight, based on the total weight of the water-based paint composition being 100 % by weight. The water-based paint composition of any one of embodiments 38 to 45, further comprising polyacrylate type rheology modifiers and / or carboxylic acid based dispersants. The water-based paint composition of embodiment 46, wherein the polyacrylate type rheology modifiers comprise (H)ASE type thickeners. The water-based paint composition of embodiment 46, wherein the carboxylic acid based dispersants are selected from the group of polyacrylic acid, polyacrylic acid compolymer, copolymer based on maleic anhydride copolymer, and mixtures of two or more thereof. The water-based paint composition of any one of embodiments 38 to 48, comprising the compound comprising at least one epoxy group in an amount in the range of from 0.01 to 1 % by weight, preferably in the range of from 0.05 to 0.5 weight-%, based on the total weight of the water-based paint composition being 100 % by weight. The water-based paint composition of any one of embodiments 38 to 49, comprising water in an amount in the range of from 5 to 60 % by weight, preferably in the range of from 20 to 30 % by weight, based on the total weight of the water-based paint composition being 100 % by weight. 51 . A coating, obtained or obtainable from application of a water-based paint composition according to embodiment 37 or according to any one of embodiments 38 to 50 to a surface, preferably to a surface of a substrate.

[0146] 52. The coating of embodiment 51 , wherein the surface is a wall and / or a ceiling of a building or a partial area thereof, preferably an interior wall and / or ceiling of a building or a partial area thereof.

[0147] The present invention is further illustrated by the following reference examples, comparative examples, and examples.

[0148] Examples

[0149] Abbreviations used wt%: % by weight

[0150] RT : room temperature (in the range of from 20 to 25 °C)

[0151] Analytics

[0152] Particle size - dynamic light scattering

[0153] Particle size was determined by using a NANO-flex particle sizer from Microtrac using 780 nm laser light (3 mW) at a 180 “scattering angle. Measurements were done with samples tel guel diluted to the reguired concentration with demineralized water at room temperature. D50 values reported refer to the volume fraction of the distribution and the polydispersity was calculated from the sigma value of the distribution divided by the D50 value and expressed as a percentage.

[0154] Solid content

[0155] Solid contents were measured on a Mettler Toledo HR 73 halogen dryer at 150 °C until a constant weight of a 0.5 to 0.8 g sample. The result is expressed in dry wt%.

[0156] Wet Scrub Resistance determination

[0157] The wet scrub resistance (WSR) of the latex paints prepared was tested by means of the nonwoven pad method in accordance to ISO 11998 (October 2006). To this end, the paint is applied to a Leneta foil with a wet film thickness of 400 pm by using a film applicator. After drying for 28 days at room temperature or 2 days at room temperature, followed by 5 days at 50 °C (accelerated testing), the coated foil is weighed and subjected to 200 wet-scrub cycles with an abrasive pad (3M or Jost) in a Erichsen or Zehnter scrub testing ma- chine in the presence of a cleaning solution. Afterwards, the scrubbed foil is rinsed with water, dried, and weighed again to determine its loss in mass. The weight loss is determined for each paint and an average value calculated. By knowing the dry film density, the abrasion in pm could finally be calculated. Chemicals

[0158] Preparation of aqueous dispersions:

[0159] Preparation of the coating formulation:

[0160] Example 1 :

[0161] In a glass beaker, 34.0 g of BADGE were dissolved in 31.28 g of MMA, 2.72 g of SMA and 0.10 g of BDDA. To the organic phase a solution of 10.88 g of surfactant 3 in 83.98 g of deionized water were added, followed by 0.43 g of NaHCC>3(s). The mixture was stirred for 15 min and then treated with ultrasound using a Bandelin Sonoplus Generator GM 2200 (200 W, 20 kHz), at 60 % power for 20 minutes per 500 g of emulsion. A stable miniemulsion was obtained, wherein the average droplet size was 158 nm.

[0162] The miniemulsion was placed in a reaction flask equipped with an overhead anchor-type stirrer, cooler, nitrogen inlet and a thermometer, heated to 45 °C and flushed with nitrogen for 15 minutes, then 2.72 g of a 10 wt% aqueous solution of t-butyl hydroperoxide was added to the miniemulsion. To the reactor 3.89 g of a 13.1 wt% aqueous solution of sodium acetone bisulfite was added in two portions: 30% of the amount in one shot at 45 °C, and the remainder 70 % of the amount over a period of 1 hour at 60 °C after the exothermic behavior was over. The reaction mixture was continuously stirred by a mechanical stirrer and was maintained at 60 °C for 1 additional hour, then cooled to 23 °C. The dispersion was filtered via a 150 pm filter. The resulting dispersion had a particle size D50 of 94 nm with a polydispersity of 36 %. The final active content (based on the epoxy compound) was 20 wt%, the solid content was 40.6 wt%. The pH was 8.5. The aspect was a white, low viscous (< 100 mPas) dispersion.

[0163] Example 2:

[0164] According to the procedure of Example 1 , using 36.0 g of C12 / 14-GE, 33.12 g of MMA, 2.88 g of SMA, 0.11 g of BDDA, 9.29 g of surfactant 1 , 91.15 g of demineralized water, 0.45 g of Na- HCO3, 4.12 g of 13.1 wt% of sodium acetone bisulfite and 2.88 g of 10 wt% t-butyl hydroperoxide.

[0165] The miniemulsion had a droplet size D50 of 128 nm and the final product a particle size D50 of 187 nm with a polydispersity of 93 %. The solid content of the white dispersion was 39.7 wt% and the pH was 8.5. The content of the epoxy compound was 20 wt%.

[0166] Example 3: According to the procedure of Example 1, using 34.0 g of Epilox P13-19, 31.28 g of MMA, 2.72 g of SMA, 0.10 g of BDDA, 8.77 g of surfactant 1, 86.09 g of demineralized water, 0.43 g of Na- HCO3, 3.89 g of 13.1 wt% of sodium acetone bisulfite and 2.72 g of 10 wt% t-butyl hydroperoxide.

[0167] The miniemulsion had a droplet size D50 of 112 nm and the final product a particle size D50 of 107 nm with a polydispersity of 82 %. The solid content of the white dispersion was 40.1 wt% and the pH was 9.0. The content of the epoxy compound was 20 wt%.

[0168] Example 4:

[0169] According to the procedure of Example 1 , using 32.0 g of ECMS-327, 29.44 g of MMA, 2.56 g of SMA, 0.10 g of BDDA, 5.69 g of surfactant 2, 83.59 g of demineralized water, 0.40 g of Na- HCO3, 3.66 g of 13.1 wt% of sodium acetone bisulfite and 2.56 g of 10 wt% t-butyl hydroperoxide.

[0170] The miniemulsion had a droplet size D50 of 333 nm and the final product a particle size D50 of 147 nm with a polydispersity of 77 %. The solid content of the white dispersion was 41.6 wt% and the pH was 9.0. The content of the epoxy compound was 20 wt%.

[0171] Example 5:

[0172] According to the procedure of Example 1, using 33.0 g of Epilox P13-19, 31.28 g of MMA, 2.72 g of SMA, 0.10 g of BDDA, 6.04 g of surfactant 2, 88.82 g of demineralized water, 0.43 g of Na- HCO3, 3.89 g of 13.1 wt% of sodium acetone bisulfite and 2.72 g of 10 wt% t-butyl hydroperoxide.

[0173] The miniemulsion had a droplet size D50 of 111 nm and the final product a particle size D50 of 161 nm with a polydispersity of 109 %. The solid content of the white dispersion was 39.0 wt% and the pH was 9.0. The content of the epoxy compound was 20 wt%.

[0174] Example 6:

[0175] According to the procedure of Example 1 , using 34.0 g of C16-GE, 31.28 g of MMA, 2.72 g of SMA, 0.10 g of BDDA, 6.04 g of surfactant 2, 88.82 g of demineralized water, 0.43 g of Na- HCO3, 3.89 g of 13.1 wt% of sodium acetone bisulfite and 2.72 g of 10 wt% t-butyl hydroperoxide.

[0176] The miniemulsion had a droplet size D50 of 75 nm and the final product a particle size D50 of 103 nm with a polydispersity of 62 %. The solid content of the white dispersion was 40.9 wt% and the pH was 9.5. The content of the epoxy compound was 20 wt%.

[0177] Example 7: According to the procedure of Example 1 , using 30.0 g of Shin-Etsu KF-101, 27.6 g of MMA, 2.40 g of SMA, 0.09 g of BDDA, 5.33 g of surfactant 2, 78.37 g of demineralized water, 0.38 g of NaHCOs, 3.44 g of 13.1 wt% of sodium acetone bisulfite and 2.40 g of 10 wt% t-butyl hydroperoxide.

[0178] The miniemulsion had a droplet size D50 of 191 nm and the final product a particle size D50 of 163 nm with a polydispersity of 55 %. The solid content of the white dispersion was 40.5 wt% and the pH was 9.0. The content of the epoxy compound was 20 wt%.

[0179] Example 8:

[0180] According to the procedure of Example 1 , using 34.0 g of Wacker Fluid IM 35, 31.28 g of MMA, 2.72 g of SMA, 0.10 g of BDDA, 6.04 g of surfactant 2, 88.82 g of demineralized water, 0.43 g of NaHCOs, 3.89 g of 13.1 wt% of sodium acetone bisulfite and 2.72 g of 10 wt% t-butyl hydroperoxide.

[0181] The miniemulsion had a droplet size D50 of 114 nm and the final product a particle size D50 of 96 nm with a polydispersity of 41 %. The solid content of the white dispersion was 39.1 wt% and the pH was 9.0. The content of the epoxy compound was 20 wt%.

[0182] Example 9:

[0183] According to the procedure of Example 1 , using 30.0 g of Shin-Etsu KF-102, 27.6 g of MMA, 2.40 g of SMA, 0.09 g of BDDA, 5.33 g of surfactant 2, 78.37 g of demineralized water, 0.38 g of NaHCOs, 3.44 g of 13.1 wt% of sodium acetone bisulfite and 2.40 g of 10 wt% t-butyl hydroperoxide.

[0184] The miniemulsion had a droplet size D50 of 266 nm and the final product a particle size D50 of 180 nm with a polydispersity of 88 %. The solid content of the white dispersion was 41.2 wt% and the pH was 9.0. The content of the epoxy compound was 20 wt%.

[0185] Example 10:

[0186] According to the procedure of Example 1 , using 34.0 g of Wacker Fluid IM 35, 31.11 g of MMA, 2.72 g of SMA, 0.10 g of BDDA, 6.04 g of surfactant 2, 89.24 g of demineralized water, 3.89 g of 13.1 wt% of sodium acetone bisulfite and 2.72 g of 10 wt% t-butyl hydroperoxide.

[0187] The miniemulsion had a droplet size D50 of 97 nm and the final product a particle size D50 of 87 nm with a polydispersity of 37 %. The solid content of the white dispersion was 40.5 wt% and the pH was 4.0. The content of the epoxy compound was 20 wt%.

[0188] Example 11 : According to the procedure of Example 1 , using 34.0 g of EFKA PL 5382, 31.28 g of MMA, 2.72 g of SMA, 0.10 g of BDDA, 6.04 g of surfactant 2, 88.82 g of demineralized water, 0.43 g of Na- HCO3, 3.89 g of 13.1 wt% of sodium acetone bisulfite and 2.72 g of 10 wt% t-butyl hydroperoxide.

[0189] The miniemulsion had a droplet size D50 of 117 nm and the final product a particle size D50 of 97 nm with a polydispersity of 45 %. The solid content of the white dispersion was 41.7 wt% and the pH was 9.0. The content of the epoxy compound was 20 wt%.

[0190] Example 12:

[0191] According to the procedure of Example 1 , using 80.0 g of EFKA PL 5382, 27.60 g of MMA, 2.40 g of SMA, 0.09 g of BDDA, 9.78 g of surfactant 2, 73.80 g of demineralized water, 0.50 g of Na- HCO3, 3.44 g of 13.1 wt% of sodium acetone bisulfite and 2.40 g of 10 wt% t-butyl hydroperoxide.

[0192] The miniemulsion had a droplet size D50 of 191 nm and the final product a particle size D50 of 191 nm with a polydispersity of 31 %. The solid content of the white dispersion was 58.05 wt% and the pH was 9.0. The content of the epoxy compound was 40 wt%.

[0193] Example 13:

[0194] According to the procedure of Example 1 , using 80.0 g of Wacker Fluid IM 35, 27.45 g of MMA, 2.40 g of SMA, 0.09 g of BDDA, 9.78 g of surfactant 2, 74.30 g of demineralized water, 3.44 g of 13.1 wt% of sodium acetone bisulfite and 2.40 g of 10 wt% t-butyl hydroperoxide.

[0195] The miniemulsion had a droplet size D50 of 332 nm and the final product a particle size D50 of 161 nm with a polydispersity of 39 %. The solid content of the white dispersion was 58.1 wt% and the pH was 5.5. The content of the epoxy compound was 40 wt%.

[0196] Example 14:

[0197] In a glass beaker, 34.0 g of Epilox P13-19 were dissolved in 9.52 g of IBMA, 8.84 g of MMA, 4.76 g of VT, 4.76 g of CHMA, 3.40 g of HEMA, 2.72 g of SMA and 0.10 g of BDDA. To the organic phase a solution of 8.77 g of surfactant 1 in 86.09 g of deionized water were added, followed by 0.43 g of NaHCC>3(s). The mixture was stirred for 15 min and then treated with ultrasound using a Bandelin Sonoplus, Generator GM 2200, 200 W, 20 kHz, at 60 % power for 20 minutes per 500 g of emulsion. A stable miniemulsion was obtained, wherein the average droplet size was 120 nm.

[0198] The miniemulsion was placed in a reaction flask equipped with an overhead anchor-type stirrer, cooler, nitrogen inlet and a thermometer, heated to 45 °C and flushed with nitrogen for 15 minutes, then 2.72 g of a 10 wt% aqueous solution of t-butyl hydroperoxide was added to the miniemulsion. To the reactor 3.89 g of a 13.1 wt% aqueous solution of sodium acetone bisulfite was added in two portions: 30% of the amount in one shot at 45 °C, and the remainder 70% of the amount over a period of 1 hour at 60 °C after the exothermic behavior was over. The reaction mixture was continuously stirred by a mechanical stirrer and was maintained at 60 °C for 1 additional hour, then cooled to 23 °C. The dispersion was filtered via a 150 pm filter. The resulting dispersion had a particle size D50 of 71 nm with a polydispersity of 32 %. The final active content (based on the epoxy compound) was 20 wt%, the solid content was 40.4 wt%. The pH was 10.0. The aspect was a white, low viscous (< 100 mPas) dispersion.

[0199] Example 15:

[0200] According to the procedure of Example 14, using 34.0 g of Epilox P13-19, 9.52 g of IBMA, 8.84 g of MMA, 4.76 g of VT, 4.76 g of CHMA, 3.40 g of HEMA, 2.72 g of SMA, 0.10 g of BDDA, 6.04 g of surfactant 2, 88.82 g of demineralized water, 0.43 g of NaHCC>3(s), 3.89 g of 13.1 wt% of sodium acetone bisulfite and 2.72 g of 10 wt% t-butyl hydroperoxide.

[0201] The miniemulsion had a droplet size D50 of 134 nm and the final product a particle size D50 of 68 nm with a polydispersity of 39 %. The solid content of the white dispersion was 40.5 wt% and the pH was 9.0. The content of the epoxy compound was 20 wt%.

[0202] Example 16:

[0203] According to the procedure of Example 14, using 36.0 g of Epilox P13-26, 10.08 g of IBMA, 9.36 g of MMA, 5.04 g of VT, 5.04 g of CHMA, 3.60 g of HEMA, 2.88 g of SMA, 0.11 g of BDDA, 9.29 g of surfactant 1 , 91.15 g of demineralized water, 0.45 g of NaHCC>3(s), 4.12 g of 13.1 wt% of sodium acetone bisulfite and 2.88 g of 10 wt% t-butyl hydroperoxide.

[0204] The miniemulsion had a droplet size D50 of 71 nm and the final product a particle size D50 of 50 nm with a polydispersity of 29 %. The solid content of the white dispersion was 40.1 wt% and the pH was 9.0. The content of the epoxy compound was 20 wt%.

[0205] Example 17:

[0206] According to the procedure of Example 14, using 36.0 g of preheated Cardolite NC-514, 10.08 g of IBMA, 9.36 g of MMA, 5.04 g of VT, 5.04 g of CHMA, 3.60 g of HEMA, 2.88 g of SMA, 0.11 g of BDDA, 9.29 g of surfactant 1 , 91.15 g of demineralized water, 0.45 g of NaHCC>3(s), 4.12 g of 13.1 wt% of sodium acetone bisulfite and 2.88 g of 10 wt% t-butyl hydroperoxide.

[0207] The miniemulsion had a droplet size D50 of 107 nm and the final product a particle size D50 of 80 nm with a polydispersity of 49 %. The solid content of the beige dispersion was 42.6 wt% and the pH was 9.0. The content of the epoxy compound was 20 wt%.

[0208] Example 18: According to the procedure of Example 14, using 36.0 g of preheated Cardolite NC-547, 10.08 g of IBMA, 9.36 g of MMA, 5.04 g of VT, 5.04 g of CHMA, 3.60 g of HEMA, 2.88 g of SMA, 0.11 g of BDDA, 9.29 g of surfactant 1 , 91.60 g of demineralized water, 4.12 g of 13.1 wt% of sodium acetone bisulfite and 2.88 g of 10 wt% t-butyl hydroperoxide.

[0209] The miniemulsion had a droplet size D50 of 171 nm and the final product a particle size D50 of 168 nm with a polydispersity of 51 %. The solid content of the beige dispersion was 41.4 wt% and the pH was 3.5. The content of the epoxy compound was 20 wt%.

[0210] Example 19:

[0211] According to the procedure of Example 14, using 72.0 g of Epilox P13-19, 7.56 g of IBMA, 7.02 g of MMA, 3.78 g of VT, 3.78 g of CHMA, 2.70 g of HEMA, 2.16 g of SMA, 0.08 g of BDDA, 12.77 g of surfactant 1 , 0.45 g of NaHCC>3(s), 62.44 g of demineralized water, 3.09 g of 13.1 wt% of sodium acetone bisulfite and 2.16 g of 10 wt% t-butyl hydroperoxide.

[0212] The miniemulsion had a droplet size D50 of 209 nm and the final product a particle size D50 of 178 nm with a polydispersity of 46 %. The solid content of the white dispersion was 52.7 wt% and the pH was 9.0. The content of the epoxy compound was 40 wt%.

[0213] Example 20:

[0214] According to the procedure of Example 14, using 80.0 g of Epilox P13-19, 8.40 g of IBMA, 7.80 g of MMA, 4.20 g of VT, 4.20 g of CHMA, 3.00 g of HEMA, 2.40 g of SMA, 0.09 g of BDDA, 9.78 g of surfactant 2, 0.50 g of NaHCC>3(s), 73.80 g of demineralized water, 3.44 g of 13.1 wt% of sodium acetone bisulfite and 2.40 g of 10 wt% t-butyl hydroperoxide.

[0215] The miniemulsion had a droplet size D50 of 188 nm and the final product a particle size D50 of 388 nm with a polydispersity of 43 %. The solid content of the white dispersion was 55.2 wt% and the pH was 9.50. The content of the epoxy compound was 40 wt%.

[0216] Example 21 :

[0217] According to the procedure of Example 14, using 44.0 g of preheated Cardolite NC-547, 12.32 g of IBMA, 11 .44 g of MMA, 6.16 g of VT, 6.16 g of CHMA, 4.40 g of HEMA, 3.52 g of SMA, 0.13 g of BDDA, 11 .35 g of surfactant 1 , 111 .40 g of demineralized water, 0.55 g of NaHCC>3(s), 5.04 g of 13.1 wt% of sodium acetone bisulfite and 3.52 g of 10 wt% t-butyl hydroperoxide.

[0218] The miniemulsion had a droplet size D50 of 165 nm and the final product a particle size D50 of 152 nm with a polydispersity of 46 %. The solid content of the beige dispersion was 41.7 wt% and the pH was 8.5. The content of the epoxy compound was 20 wt%.

[0219] Example 22: According to the procedure of Example 14, using 80.0 g of preheated Cardolite NC-514, 8.40 g of IBMA, 7.80 g of MMA, 4.20 g of VT, 4.20 g of CHMA, 3.00 g of HEMA, 2.40 g of SMA, 0.09 g of BDDA, 14.19 g of surfactant 1 , 93.38 g of demineralized water, 0.50 g of NaHCO3(s), 3.44 g of 13.1 wt% of sodium acetone bisulfite and 2.40 g of 10 wt% t-butyl hydroperoxide. Before filtration, the dispersion was set to pH ~4 by dropwise addition of glacial acetic acid.

[0220] The miniemulsion had a droplet size D50 of 241 nm and the final product a particle size D50 of 231 nm with a polydispersity of 44 %. The solid content of the beige dispersion was 58.9 wt% and the pH was 4.1. The content of the epoxy compound was 40 wt%.

[0221] Example 23:

[0222] According to the procedure of Example 14, using 100.0 g of preheated Cardolite NC-547, 10.50 g of IBMA, 9.75 g of MMA, 5.25 g of VT, 5.25 g of CHMA, 3.75 g of HEMA, 3.00 g of SMA, 0.11 g of BDDA, 17.74 g of surfactant 1 , 86.73 g of demineralized water, 0.63 g of NaHCC>3(s), 4.29 g of 13.1 wt% of sodium acetone bisulfite and 3.00 g of 10 wt% t-butyl hydroperoxide.

[0223] The miniemulsion had a droplet size D50 of 446 nm and the final product a particle size D50 of 518 nm with a polydispersity of 79 %. The solid content of the beige dispersion was 56.0 wt% and the pH was 9.2. The content of the epoxy compound was 40 wt%.

[0224] Example 24:

[0225] A 80.0 g portion of Example 23 was placed in a beaker and set to pH ~ 4 by dropwise addition of glacial acetic acid under stirring. The final product a particle size D50 of 527 nm with a polydispersity of 65 %. The solid content of the beige dispersion was 56.7 wt% and the pH was 4.1. The content of the epoxy compound was 40 wt%.

[0226] Example 25:

[0227] According to the procedure of Example 14, using 73.50 g of preheated Cardolite NC-514, 13.72 g of IBMA, 12.74 g of MMA, 6.86 g of VT, 6.86 g of CHMA, 4.90 g of HEMA, 3.92 g of SMA, 0.15 g of BDDA, 15.81 g of surfactant 1 , 96.40 g of demineralized water, 0.61 g of NaHCC>3(s), 5.61 g of 13.1 wt% of sodium acetone bisulfite and 3.92 g of 10 wt% t-butyl hydroperoxide.

[0228] The miniemulsion had a droplet size D50 of 160 nm and the final product a particle size D50 of 143 nm with a polydispersity of 33 %. The solid content of the beige dispersion was 53.26 wt% and the pH was 8.5. The content of the epoxy compound was 30 wt%.

[0229] Example 26: A 100.0 g portion of Example 25 was placed in a beaker and set to pH ~ 5 by dropwise addition of glacial acetic acid under stirring. The final product a particle size D50 of 127 nm with a polydispersity of 45 %. The solid content of the beige dispersion was 54.1 wt% and the pH was 5.1. The content of the epoxy compound was 30 wt%.

[0230] Example 27:

[0231] According to the procedure of Example 14, using 49.0 g of Epilox A19-03, 13.72 g of IBMA, 12.74 g of MMA, 6.86 g of VT, 6.86 g of CHMA, 4.90 g of HEMA, 3.92 g of SMA, 0.15 g of BDDA, 12.65 g of surfactant 1 , 124.06 g of demineralized water, 0.61 g of NaHCC>3(s), 5.61 g of 13.1 wt% of sodium acetone bisulfite and 3.92 g of 10 wt% t-butyl hydroperoxide.

[0232] The miniemulsion had a droplet size D50 of 142 nm and the final product a particle size D50 of 102 nm with a polydispersity of 68 %. The solid content of the white dispersion was 42.7 wt% and the pH was 8.8. The content of the epoxy compound was 20 wt%.

[0233] Example 28:

[0234] A 100.0 g portion of Example 27 was placed in a beaker and set to pH ~ 5 by dropwise addition of glacial acetic acid under stirring. The final product a particle size D50 of 116 nm with a polydispersity of 78 %. The solid content of the white dispersion was 42.2 wt% and the pH was 5.5. The content of the epoxy compound was 20 wt%.

[0235] Example 29:

[0236] According to the procedure of Example 14, using 49.0 g of Epilox A18-00, 13.72 g of IBMA, 12.74 g of MMA, 6.86 g of VT, 6.86 g of CHMA, 4.90 g of HEMA, 3.92 g of SMA, 0.15 g of BDDA, 12.65 g of surfactant 1 , 124.06 g of demineralized water, 0.61 g of NaHCC>3(s), 5.61 g of 13.1 wt% of sodium acetone bisulfite and 3.92 g of 10 wt% t-butyl hydroperoxide.

[0237] The miniemulsion had a droplet size D50 of 169 nm and the final product a particle size D50 of 101 nm with a polydispersity of 65 %. The solid content of the white dispersion was 42.4 wt% and the pH was 8.3. The content of the epoxy compound was 20 wt%.

[0238] Example 30:

[0239] A 120.0 g portion of Example 29 was placed in a beaker and set to pH ~ 5 by dropwise addition of glacial acetic acid under stirring. The final product a particle size D50 of 85 nm with a polydispersity of 38 %. The solid content of the white dispersion was 42.2 wt% and the pH was 5.3. The content of the epoxy compound was 20 wt%.

[0240] Example 31 : According to the procedure of Example 14, using 49.0 g of Epilox A19-04, 13.72 g of IBMA, 12.74 g of MMA, 6.86 g of VT, 6.86 g of CHMA, 4.90 g of HEMA, 3.92 g of SMA, 0.15 g of BDDA, 12.65 g of surfactant 1 , 124.06 g of demineralized water, 0.61 g of NaHCO3(s), 5.61 g of 13.1 wt% of sodium acetone bisulfite and 3.92 g of 10 wt% t-butyl hydroperoxide.

[0241] The miniemulsion had a droplet size D50 of 154 nm and the final product a particle size D50 of 147 nm with a polydispersity of 84 %. The solid content of the white dispersion was 42.2 wt% and the pH was 8.8. The content of the epoxy compound was 20 wt%.

[0242] Example 32:

[0243] A 120.0 g portion of Example 31 was placed in a beaker and set to pH ~ 5 by dropwise addition of glacial acetic acid under stirring. The final product a particle size D50 of 92 nm with a polydispersity of 51 %. The solid content of the white dispersion was 42.3 wt% and the pH was 5.5. The content of the epoxy compound was 20 wt%.

[0244] Example 33:

[0245] According to the procedure of Example 14, using 49.0 g of Epilox F17-00, 13.72 g of IBMA, 12.74 g of MMA, 6.86 g of VT, 6.86 g of CHMA, 4.90 g of HEMA, 3.92 g of SMA, 0.15 g of BDDA, 12.65 g of surfactant 1 , 124.06 g of demineralized water, 0.61 g of NaHCC>3(s), 5.61 g of 13.1 wt% of sodium acetone bisulfite and 3.92 g of 10 wt% t-butyl hydroperoxide.

[0246] The miniemulsion had a droplet size D50 of 298 nm and the final product a particle size D50 of 224 nm with a polydispersity of 81 %. The solid content of the white dispersion was 42.5 wt% and the pH was 8.3. The content of the epoxy compound was 20 wt%.

[0247] Example 34:

[0248] A 120.0 g portion of Example 33 was placed in a beaker and set to pH ~ 5 by dropwise addition of glacial acetic acid under stirring. The final product a particle size D50 of 434 nm with a polydispersity of 108 %. The solid content of the white dispersion was 42.9 wt% and the pH was 5.3. The content of the epoxy compound was 20 wt%.

[0249] Example 35:

[0250] According to the procedure of Example 14, using 51.0 g of molten 4,4'-Methylen-bis-(N,N-di- glycidylanil in) , 9.52 g of IBMA, 8.84 g of MMA, 4.76 g of VT, 4.76 g of CHMA, 3.40 g of HEMA, 2.72 g of SMA, 0.10 g of BDDA, 10.97 g of surfactant 1 , 66.89 g of demineralized water, 0.55 g of NaHCC>3(s), 3.89 g of 13.1 wt% of sodium acetone bisulfite and 2.72 g of 10 wt% t-butyl hydroperoxide. The preparation of the organic phase was done at 50 °C. The miniemulsion had a droplet size D50 of 216 nm and the final product a particle size D50 of 307 nm with a polydispersity of 58 %. The solid content of the off-white dispersion was 52.2 wt% and the pH was 8.6. The content of the epoxy compound was 30 wt%.

[0251] Example 36:

[0252] According to the procedure of Example 14, using 46.5 g of molten Tris(4-hydroxyphenyl)me- thane triglycidylether, 8.68 g of IBMA, 8.06 g of MMA, 4.34 g of VT, 4.34 g of CHMA, 3.10 g of HEMA, 2.48 g of SMA, 0.09 g of BDDA, 10.00 g of surfactant 1 , 60.99 g of demineralized water, 0.39 g of NaHCC>3(s), 3.55 g of 13.1 wt% of sodium acetone bisulfite and 2.48 g of 10 wt% t-bu- tyl hydroperoxide. The preparation of the organic phase was done at 60 °C.

[0253] The miniemulsion had a droplet size D50 of 253 nm and the final product a particle size D50 of 306 nm with a polydispersity of 38 %. The solid content of the yellowish dispersion was 52.0 wt% and the pH was 8.6. The content of the epoxy compound was 30 wt%.

[0254] Example 37:

[0255] According to the procedure of Example 14, using 25.0 g of preheated Joncryl ADR 4385, 7.00 g of IBMA, 6.50 g of MMA, 3.50 g of VT, 3.50 g of CHMA, 2.50 g of HEMA, 2.00 g of SMA, 0.08 g of BDDA, 6.45 g of surfactant 1 , 63.30 g of demineralized water, 0.31 g of NaHCC>3(s), 2.86 g of 13.1 wt% of sodium acetone bisulfite and 2.00 g of 10 wt% t-butyl hydroperoxide.

[0256] The miniemulsion had a droplet size D50 of 131 nm and the final product a particle size D50 of 102 nm with a polydispersity of 60%. The solid content of the yellowish dispersion was 42.4 wt% and the pH was 8.6. The content of the epoxy compound in the formulation was 20 wt%.

[0257] Example 38 (NEGATIVE CONTROL)

[0258] In a five-necked flask equipped with a cooler, stirrer, thermometer and nitrogen inlet, 60.0 g of Cardolite NC-514 (containing 0.236 mol of epoxy groups), 11.0 g of ethanol (0.239 mol) and 100 g of dry ethylacetate were placed and homogenously dissolved at RT under an N2 atmosphere. In an addition funnel, 0.45 g of BF3.OEt2 was dissolved in 4.5 g of ethanol (0,098 mol) and added slowly to the stirred reaction mixture at RT over 5 minutes. A slight exotherm of a few degrees was observed. Then the mixture was heated to 75 °C and further reacted for two hours. Subsequently, the solvent and excess of ethanol were distilled off at 20 mbar and 75 °C until a solid content of 99,5% was reached. The obtained dark brown viscous liquid (60.5 g) was analyzed by1H NMR in CDCI3 to confirm that none of the proton signals of the epoxygroup (2.75, 2.88 and 3.35 ppm)) remained visible in the spectrum, indicating the full conversion of the epoxygroups to the open hydroxyethylethers.

[0259] The obtained hydroxyethylether was encapsulated according to the procedure of Example 14, using 50.01 g of preheated compound of the previous procedure, 9.34 g of IBMA, 8.67 g of MMA, 4.67 g of VT, 4.67 g of CHMA, 3.33 g of HEMA, 2.67 g of SMA, 0.10 g of BDDA, 10.75 g of surfactant 1, 65.59 g of demineralized water, 0.42 g of NaHCO3(s), 3.82 g of 13.1 wt% of sodium acetone bisulfite and 2.67 g of 10 wt% t-butyl hydroperoxide.

[0260] The miniemulsion had a droplet size D50 of 240 nm and the final product a particle size D50 of 224 nm with a polydispersity of 54 %. The solid content of the dark beige dispersion was 53.5 wt% and the pH was 8.5. The content of the hydroxyethylether was 30 wt%.

[0261] Application testing in waterborne coating formulation

[0262] The following interior coating formulation with a PVC (pigment volume concentration, ratio of the volume of pigment to the total volume of solid pigment plus solid binder, v:v) of 76% and a solids content of 62 wt% was prepared using the following formulation:

[0263] Waterborne interior paint for architectural applications

[0264] As rheology modifier standard HASE thickener (reference, ref.) Rheovis HS 1152 and as binder styrene acrylic binder Acronal 6292 were used. In the following chart the shown amount of rheology modifier was added in the order shown above and the shown amounts of examples 1 - 36 where post-added into the final paint. The resulting paints were stored over night at room temperature and the rheological profile was determined with an "Anton Paar MCR 302” rheometer with a cone-plate geometry of 25 mm diameter, Tangle (CP 25-1) between a shear rate of 0.1 and 10000 s’1. In Tables 1 to 7 the results of the measurements are summarized, wherein the following abbreviations were used: Comp: Comparative Example, Inv: Inventive Example, Ref: Reference Example.

[0265] Table 1

[0266] Test series A, B and C

[0267] All inventive samples also in all tested concentrations showed an improved wet scrub resistance compared to the reference (Rheovis HS 1152) alone, visible in significantly lower abrasion levels.

[0268] In the following series E and F the amount of HASE thickener was increased, what resulted directly in higher abrasion levels.

[0269] Table 2 Test series E and F

[0270] Also, in these examples it could be seen that the inventive examples 69-74 and 76 -79 could improve the wet scrub resistance of a paint formulated with HASE thickeners. In the following set of results - test series G, H, I and K- a harder batch of scrub pads was used in order to assess the discrimination of the performance if the inventive additives are even better, which translates into higher overall abrasion levels. Conditions and results are shown below in Table 3. In these series also the effect on state-of-the-art cellulose thickeners like Natrosol 250 HR was shown.

[0271] Table 3

[0272] Test series G,

[0273] It can be seen from the table that the HASE thickener (SoA) are not at the scrub resistance level of the cellulose thickeners (SoA), which generally are showing much lower abrasion levels. Additionally, all mentioned inventive examples show improved scrub resistance compared to all references.

[0274] In the following Table 4 the rheology data of the paints made with (Inv) and without (Comp) additional of the wet scrub booster are listed:

[0275] Table 4 Rheology data of the paints made from T est series A to K

[0276] It could be seen that by addition of the wet scrub additives in the inventive examples the rheology curve was not significantly changed, so this approach had minor influence on rheology when a HASE was used in the formulation as well as when a cellulose thickener was used (see example 81 + 82)

[0277] To broaden the applicability of the wet scrub additives, polyester-polyurethane dispersions and pure acrylic dispersions were also tested as binders in addition to styrene acrylic dispersions (Test series L). To this end, all three binder technologies were formulated according to the above-described guiding formulation keeping the binder solids content constant and using a cellulose thickener (4 wt% Tylose MH 30000 YP4). The following table 5 highlights the measured abrasion levels:

[0278] Table 5 Abrasion levels - T est series L

[0279] It could be seen that the addition of the wet scrub additive significantly improved the wet scrub resistance of all formulated paints, regardless of the binder technology. To illustrate the storage stability of the wet scrub additive, another test series N was performed in which formulated paints based on Acronal® 6292 and Tylose MH 30000 YP4 with and without wet scrub additive were stored for four months at room temperature, followed by measurement of the wet scrub resistance. Conditions and results are listed below in Table 6: Table 6

[0280] Storage time and wet scrub resistance - Test series N

[0281] The improvement of the wet scrub resistance is still visible after a paint storage time of 4 months. To further illustrate the necessity of the encapsulated active ingredient, also a negative control was performed. To this end, example 38, whose epoxide crosslinker was hydrolyzed in advance, was formulated according the above-described guiding formulation, followed by determination of the wet scrub resistance. Conditions and results are listed below in Table 7:

[0282] Table 7

[0283] Test series O

[0284] Indeed, the addition of 0.5 wt% of example 38 resulted in a very similar abrasion like the reference and did not come close to the 40% abrasion improvement found for example 25, indicating the need of the active compound. The small difference of 1 pm could be explained either by the standard deviation of the test method or by the introduction of some hard phase by the capsules.

[0285] Cited Literature

[0286] US 2012 / 115999 A1

[0287] WO 2011 / 012631 A1

[0288] EP 1 664 128 B1

[0289] US 2017 / 0247570 A1

[0290] CA 2156468 A1

[0291] E P 1 213 317 A2

[0292] WO 2006 / 111290 A 1

[0293] WO 2022 / 169796 A 1

Claims

Claims1. An aqueous dispersion comprising polymer particles, the polymer particles comprising(a) a polymer carrier obtained or obtainable from at least one ethylenically unsaturated monomer (a.1);(b) a compound comprising at least one epoxy group; wherein the polymer carrier of (a) and the compound of (b) are not covalently bonded to each other; and wherein the aqueous dispersion comprises less than 1000 weight-ppm of an organic solvent.

2. The aqueous dispersion of claim 1 , wherein > 95 % of the polymer particles have a diameter of < 1000 nm, preferably in the range of from 20 to 1000 nm, more preferably in the range of from 20 to 500 nm, more preferably in the range of from 30 to 300 nm, determined by dynamic light scattering (DLS).

3. The aqueous dispersion of claim 1 or 2, wherein the compound containing at least one epoxy group according to (b) is present in an amount in the range of from 10 to 90 % by weight, preferably in the range of from 25 to 75 % by weight, more preferably in the range of from 40 to 60 % by weight based on the total weight of the polymer particle being100 % by weight.

4. The aqueous dispersion of any one of claims 1 to 3, wherein the compound containing at least one epoxy group according to (b) is selected from mono-functional epoxy compound, multifunctional epoxy compound, epoxy-functional oligomer, epoxy-functional polymer, wherein an epoxy-functional polymer is preferably selected from the group consisting of epoxy-functional polysiloxane, epoxy-functional polyacrylate, epoxy-functional polybutadiene and mixtures of two or more thereof; wherein the compound containing at least one epoxy group according to (b) is preferably selected from multifunctional epoxy compound, epoxy-functional oligomer and mixtures of these two, each having an epoxy-functional ity > 1 , more preferably > 2.

5. The aqueous dispersion of any one of claims 1 to 4, wherein the compound containing at least one epoxy group according to (b) is selected from the group consisting of glyc- idylether of aliphatic alcohol, glycidylether of aromatic alcohol, glycidylether of multifunctional aliphatic alcohol, glycidylether of aromatic alcohol, wherein the aliphatic alcohol, aromatic alcohol, multifunctional aliphatic alcohol and aromatic alcohol each have more than 6 carbon atoms, diglycidylether of difunctional aliphatic cyclic alcohol, diglycidylether ofdifunctional aliphatic branched alcohol, diglycidylether of difunctional aliphatic linear alcohol, glycidylether of glyceride, glycidyl ether of partial glyceride, Bisphenol-A-diglyc- idylether, oligomer composed of Bisphenol-A-diglycidylether, Bisphenol-F-diglycidylether, oligomer composed of Bisphenol-F-diglycidylether, polysiloxane-based structure with pending glycidyl groups, modified or unmodified novolac epoxy resin (phenol and cresol types), tetraglycidyl ether of tetraphenol ethane, glycidyl ether of mono- or polyfunctional alkoxylate, (meth)acrylic / styrenic copolymers with epoxy functionality, glycidylester of mono or polyfunctional carboxylic acid, (acrylic) (co)polymer / oligomer based on glyc- idyl(meth)acrylate as monomer, and mixtures of two or more thereof; wherein the compound containing at least one epoxy group according to (b) is selected from the group consisting of bisphenol A diglycidyl ether, dodecyl / tetradecyl-glycidylether, branched CISCIS glycidylether, glycidyl-hexadecylether, (epoxycyclohexylethyl)methylsiloxane-dime- thylsiloxane copolymer, linear polydimethylsiloxane with terminal epoxy groups, linear comb-type poylsiloxane with pending glycidyl groups having a functional group equivalent weight in the range of from 300 to 4000 g / mol, epoxidized soybean oil, diglycidyl ether based on cyclohexanedimethanol, monoglycidyl ether based on C13-C15-alkohols, bisphenol F-resin (phenol-formaldehyde polymer glycidyl ether), bisphenol A-resin having a viscosity in the range of from 5 to 20 Pas at 25 °C, diglycidyl ether epoxy resin, polyglyc- idyl ether of an alkenyl phenol formaldehyde novolac resin, 4,4'-Methylen-bis-(N,N-diglyc- idylani lin) , tris(4-hydroxyphenyl)methane triglycidylether, poly(meth)acrylate with epoxyfunctionality, copolymer based on (meth)acrylate and (methyl)styrene with epoxy-function- ality, and mixtures of two or more thereof; wherein the compound containing at least one epoxy group according to (b) is more preferably selected from the group consisting of epoxide, which is derived from a mono or multi unsaturated nonpolar compound by epoxidation of the corresponding double bond(s), more preferably selected from the group consisting of unsaturated non-polar compound of natural origin, the unsaturated non-polar compound of natural origin preferably being selected from the group consisting of sunflower oil, tall oil, soy-bean oil, castor oil, linseed oil, palm oil, rapeseed oil, cashew nutshell liquid, and mixtures of two or more thereof, cardanol, natural rubber, sucrose soyate, terpene based compound, and mixtures of two or more thereof.

6. The aqueous dispersion of any one of claims 1 to 5, wherein the ethylenically unsaturated monomer (a.1), from which the polymer according to (a) is obtained or obtainable, is selected from the group consisting of C1-C20 (meth)acrylate, styrene, vinyltoluene, hydroxyfunctional C1-C20 (meth)acrylate, (meth)acrylate derived from alkoxylated alcohol, multifunctional (meth)acrylate, and mixtures of two or more thereof; wherein the polymer ac-cording to (a) preferably comprises at least one polymer selected from the group consisting of poly(meth)acrylate, styrene-acrylate copolymer, vinylester polymer, vinylester copolymer, copolymer of ethylene and vinylacetate, copolymer of vinylacetate and acrylate, polybutadiene, copolymer of styrene and butadiene, polyester, copolyester, polyurethane, and mixtures of two or more thereof; wherein the polymer according to (a) more preferably comprises at least one polymer selected from the group consisting of stearyl methacrylate, methyl methacrylate, butanediol diacrylate, isobutylmethacrylate, vinyl toluene, cyclohexylmethacrylate, 2-hydroxyethylmethacrylate, and mixtures of two or more thereof; wherein the polymer according to (a) more preferably comprises at least one polyacrylate copolymer obtained or obtainable from a mixture of at least two ethylenically unsaturated monomers (a.1), wherein > 50 % by weight of the mixture are two or more (meth)acrylate monomers, based on the total weight of the mixture being 100 % by weight.

7. The aqueous dispersion of any one of claims 1 to 6, further comprising(c) at least one surfactant; wherein the at least one surfactant according to (c) is preferably selected from the group consisting of non-ionic surfactant, cationic surfactant, anionic surfactant and mixtures of two or more thereof, more preferably from the group consisting of non-ionic surfactant, anionic surfactant and mixture of non-ionic surfactant and anionic surfactant, more preferably from the group consisting of alkali and ammonium salt of C12-C16 alkylsulfonic acid, dialkyl ester of succinic acid, monoalkyl ester of succinic acid, or sulfuric acid halfester of ethoxylated alkanole, C12-C18 alkylgylcoside, aliphatic or araliphatic compound, preferably ethoxylated phenol (mon, di, tri) with an ethoxylation degree of 3 to 50 and alkyl groups in the range from C4-C9, ethoxylated long chain alcohol, polyethyleneoxide / poly- propyleneoxide block copolymer and mixtures of two or more thereof.

8. A method for preparing an aqueous dispersion comprising polymer particles, the polymer particles comprising(a) a polymer carrier obtained or obtainable from at least one ethylenically unsaturated monomer (a.1);(b) a compound comprising at least one epoxy group;(c) optionally at least one surfactant; the method comprising radical polymerization of the at least one ethylenically unsaturated monomer (a.1) within an aqueous emulsion comprising the compound comprising at least one epoxy group (b), the at least one ethylenically unsaturated monomer (a.1) and optionally the at least one surfactant (c);wherein the aqueous emulsion comprises less than 1000 weight-ppm of one or more organic solvent(s).

9. An aqueous dispersion comprising polymer particles, the polymer particles comprising(a) a polymer carrier obtained or obtainable from at least one ethylenically unsaturated monomer (a.1), wherein the at least one ethylenically unsaturated monomer (a.1) is preferably selected from the group consisting of C1-C20 (meth)acrylate, styrene, vi- nyltoluene, hydroxy-functional C1-C20 (meth)acrylate, (meth)acrylate derived from alkoxylated alcohol, multifunctional (meth)acrylate, and mixtures of two or more thereof;(b) a compound comprising at least one epoxy group,(c) optionally at least one surfactant, obtained or obtainable from the method of claim 8.

10. Use of an aqueous dispersion comprising polymer particles, the polymer particles comprising (a) a polymer carrier obtained or obtainable from at least one ethylenically unsaturated monomer (a.1), (b) a compound comprising at least one epoxy group, and (c) optionally at least one surfactant, wherein the polymer carrier of (a) and the compound of (b) are not covalently bonded to each other; and wherein the aqueous dispersion comprises less than 1000 weight-ppm of an organic solvent, as additive for a water borne coating; wherein the aqueous dispersion is preferably used as additive for improving abrasion resistance of a water borne coating, preferably for improving wet-scrub resistance of a water borne coating; wherein the water borne coating is preferably a paint or an ink, more preferably a paint, more preferably an interior wall paint and / or an interior architectural paint.

11. A water-based paint composition, obtained or obtainable by adding an aqueous dispersion comprising polymer particles according to any one of claims 1 to 7 to a water-based paint.

12. A water-based paint composition comprising polymer particles, the polymer particles comprising (a) a polymer carrier obtained or obtainable from at least one ethylenically unsaturated monomer (a.1), (b) a compound comprising at least one epoxy group, and (c) optionally at least one surfactant, wherein the polymer carrier of (a) and the compound of (b) are not covalently bonded to each other; and wherein the water-based paint composition comprises less than 1000 weight-ppm of an organic solvent.

13. The water-based paint composition of claim 12,further comprising at least one binder, preferably a binder selected from the group consisting of synthetic resin, natural resin or mixture of synthetic and natural resin, preferably selected from the group consisting of alkyd, acrylic polymer, styrene acrylic polymer, vinylacrylic polymer, vinyl acetate / ethylene polymer, polyurethane, polyester, polyester polyurethane, melamine resin, polyepoxide, silane, siloxane, oil or mixtures of two or more thereof, more preferably from the group consisting of styrene acrylic polymer, acrylic polymer, polyester polyurethane and mixtures of two or three thereof, preferably in an amount in the range of from 10 to 80 %by weight, more preferably in the range of from 20 to 70 % by weight, based on the total weight of the water-based paint composition being 100 % by weight; and / or, preferably and, further comprising at least one filler, preferably a filler selected from the group consisting of talc, diatomite, mica, aluminum silicate, calcium carbonate and mixtures of two or more thereof, preferably in an amount in the range of from 1 to 30 %by weight, more preferably in the range of from 5 to 20 % by weight, based on the total weight of the water-based paint composition being 100 % by weight; and / or, preferably and, further comprising at least one colorant in an amount in the range of from 0.1 to 25 %by weight, preferably in the range of from 5 to 10 % by weight, based on the total weight of the water-based paint composition being 100 % by weight.

14. A coating, obtained or obtainable from application of a water-based paint composition according to claim 11 or according to claim 12 or 13 to a surface; wherein the surface is preferably a wall and / or a ceiling of a building or a partial area thereof, more preferably an interior wall and / or ceiling of a building or a partial area thereof.

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