WO2011069891A1

WO2011069891A1 - Method for producing charge-structured coatings

Info

Publication number: WO2011069891A1
Application number: PCT/EP2010/068787
Authority: WO
Inventors: Uwe Hartnagel; Albert Budiman Sugiharto; Frank Wilco Bartels; Thomas Servay
Original assignee: Basf Se
Priority date: 2009-12-08
Filing date: 2010-12-03
Publication date: 2011-06-16

Abstract

The invention relates to coatings having a periodic structure of the surface potential on the basis of polymer lattices, and to a method for producing coatings having a periodic structure of the surface potential, comprising the following steps: (a) providing at least one first polymer dispersion as component A and at least one second polymer dispersion as component B, wherein components A and B differ from each other with respect to the chemical compositions thereof, (b) mixing the polymer dispersions from step (a) and optionally further components, wherein the weight ratio of component A to component B in the mixture is from 95:5 to 60:40, in relation to the solids content, (c) applying the mixture from step (b) onto a surface, preferably a substrate, (d) compacting the mixture from step (c) forming a coating, and (e) further chemical reaction of the coating obtaining a periodic structure of the surface potential, wherein the ratio of the weight-average particle diameter of component A to that of component B ranges from 3:1 to 15:1, the weight-average particle diameter of component A ranges from 75 to 1000 nm, and the weight-average particle diameter of component B ranges from 10 to 200 nm. The invention further relates to the coatings that can be thus obtained and to the use of coatings having a periodic structure of the surface potential on the basis of polymer lattices to reduce the formation of films.

Description

The invention relates to coatings having a periodic structure of the surface potential on the basis of polymer latices and to a process for producing coatings having a periodic structure of the surface potential, comprising the following steps:

(A) providing at least one first polymer dispersion as component A and at least one second polymer dispersion as component B, wherein the

Distinguish components A and B in their chemical composition,

(b) mixing the polymer dispersions of step (a) and optionally other components wherein the weight ratio of component A to component B in the mixture is 95 to 5 to 60 to 40 based on solids content; (c) applying the mixture of step (b) on a surface, preferably a substrate,

(d) solidifying the mixture of step (c) to form a coating, and

(e) further chemical conversion of the coating to obtain a periodic structure of the surface potential,

wherein the ratio of the weight average particle diameter of the component A to that of the component B is 3 to 1 to 15 to 1, the weight average particle diameter of the component A is 75 to 1000 nm, and the weight average particle diameter of the component B is 10 to 200 nm. Moreover, the invention relates to the coatings thus obtainable and the use of coatings having a periodic structure of the surface potential on the basis of polymer latexes to reduce deposit formation.

Coatings or films which are obtained starting from dispersion mixtures having different particle sizes are known per se.

EP 1 685 859 A2 discloses film-forming compositions containing polymer particles of different sizes and glass transition temperatures. The resulting films are particularly suitable as a wound dressing. However, the resulting films are not patterned. EP 0 612 805 A2 discloses film-forming compositions which are obtained starting from mixtures of polymer dispersions. The respective polymer dispersions differ with respect to the glass transition temperature and particle size of the polymer particles. However, the polymer films or polymer layers obtained therefrom have no surfaces which are periodically structured with respect to the surface potential.

The properties of the known coatings on the basis of polymer latexes are not sufficient in terms of deposit formation and deposit adhesion, in particular with regard to the reduction of the adhesion of lime deposits for many applications.

The formation of deposits is understood to mean the formation or adhesion of deposits (deposits) on the surface of the coating. These are in particular lime deposits to be understood, which arise by evaporation of water. Agents which inhibit the formation of the abovementioned deposits are known to the person skilled in the art as "antiscalants".

Accordingly, it was an object of the present invention to provide coatings based on polymer dispersions, which do not have the aforementioned disadvantages. The corresponding film-forming compositions should have a wide range of applications and can be used, for example, in paints. The resulting coatings should have a low tendency to scale adhesion, especially with regard to limescale adhesion. Once formed, especially limescale, it should be easy to detach from the surface, e.g. by rinsing.

These objects are achieved by the coatings according to the invention, by the method according to the invention and by the coatings thus obtainable. Preferred embodiments are to be taken from the description and the claims. Combinations of preferred embodiments described below do not depart from the scope of the present invention, in particular as far as the combination of individual embodiments of the method steps is concerned.

The present invention relates to coatings having a periodic structure of the surface potential based on polymer latices and to a process for producing coatings having a periodic structure of the surface potential, comprising the following steps in the order of abcde:

Distinguish components A and B in their chemical composition,

(d) solidifying the mixture of step (c) to form a coating, and

(e) further chemically reacting the coating to obtain a periodic structure of the surface potential, wherein the ratio of the weight average particle diameter of the component A to that of the component B is from 3 to 1 to 15 to 1, the weight average particle diameter of the component A is from 75 to 1000 nm and the weight average particle diameter of the component B is from 10 to 200 nm.

The term "surface potential" in the context of the present invention has the meaning according to IUPAC Compendium of Chemical Technology, 2nd Edition (1997), according to which surface potential is to be understood as the drop in the electrical potential at the surface of the coating The surface potential of the coatings according to the invention is periodic Therefore, the surface potential has a local value (for a given location on the surface of the coating) and results in its local spatial dimension from the dispersion particles used. The term "periodic structure of the surface potential" denotes a substantially recurring spatial sequence of regions of different surface potential , The spatial dimension of the periodically repeating structure is preferably in the range from 1 to 1000 nm (hereinafter referred to as "nanostructured") .The spatial dimension of the periodically recurring structure is characterized in particular by the size of the particles of components A and B. The term "periodic structure of the surface potential" is used in the context of the present invention synonymously with the term "charge structure" or "charge-structured." The charge structure is based on local and periodically recurring different charge states (positive, neutral, negative) or on different states of charge states A charge structure in the sense of the present invention is present when the difference of the surface potentials of the periodically recurring regions and thus of the components A and B is at least 20 mV Preferably, the difference of the surface potentials is at least 40 mV, in particular at least 60 mV, particularly preferably at least 80 mV, very particularly preferably at least 100 mV.

It is preferred in the context of the present invention if the charge structure is based on a spatially recurring sequence of positive and negative surface potentials or on a spatially recurring sequence of positive and substantially neutral surface potentials or on a spatially recurring sequence of negative and substantially neutral surface potentials based. It is particularly preferred if the charge structure is based on a spatially recurring sequence of positive and negative surface potentials. The surface potentials are determined spatially resolved in the context of the present invention by means of Kelvin probe force microscopy (Kelvin probe force microscopy). The method is known to the person skilled in the art and is explained, for example, in Advanced Materials, 2006, 18, 145-164. Using Kelvin probe force microscopy, the local potential of the sample surface can be imaged with high resolution. For this purpose, a conductive cantilever tip is used as a metallic probe to determine the potential difference between the tip and the sample surface. The reference material is a gold substrate. In Kelvin probe force microscopy, the electrostatic forces acting on the tip are used as a control signal during the scanning of the sample. h., one

Control circuit minimizes the interaction between a conductive AFM tip and the Sample surface by compensating the potential difference with an external DC voltage.

The term "polymer dispersion" denotes polymer particles dispersed in a liquid phase, which is preferably water The polymer dispersions of components A and B used are stable, i.e. invariable over a period of at least 24 hours, in particular no coagulation occurs.

In the context of the present invention, the determination of the weight-average particle diameter is basically carried out by means of analytical ultracentrifuge. Corresponding methods are known to the person skilled in the art. By weight-average particle diameter is within the scope of the present invention as determined by the method of the analytical ultracentrifuge weight-average D _W 5o value understood (see. This SE Har- ding et al., Analytical ultracentrifugation in Biochemistry and Polymer Science, Royal Society of Chemistry, Cambridge , Great Britain 1992, Chapter 10, Analysis of Polymer Dispersions with Eight Cell AUC Multiplexers: High Resolution Particle Size Distribution and Density Gradient Techniques, W. Mächtie, pp. 147-175).

Within the scope of this document, narrow particle size distribution is to be understood as meaning the ratio of the weight-average particle diameter D _w determined by the method of the analytical ultracentrifuge and the number-average particle diameter DN 50 [D _W 5O / DN 50] <2.0, preferably <1.5 , particularly preferably <1, 2 and in particular <1, 1.

The mixture of components A and B resulting from step (b) is a film-forming composition in the context of the present invention. By film-forming composition is meant such a composition which forms a (polymer) film under suitable conditions upon removal of the liquid phase, preferably with crosslinking of the polymer particles. The term "film" and the term "coating" is used interchangeably in the context of the present invention.

According to the method according to the invention for the preparation of charge-structured coatings, according to step (a) the provision of at least one first polymer dispersion as component A and at least one second polymer dispersion as component B takes place, wherein the components A and B are used in their chemical compositions. and wherein the ratio of the weight average particle diameter of the component A to that of the component B in the mixture of 3 to 1 to 15 to 1, the weight average particle diameter of the component A of 75 to 1000 nm and the weight average particle diameter of the component B of 10 to 200 nm.

Preferably, the ratio of the weight average particle diameter of component A to that of component B is from 4: 1 to 10: 1, and more preferably from 4.5: 1 to 7: 1.

The mixture is carried out in the context of step (b) of the method according to the invention while avoiding coagulation. The person skilled in the art thus selects the polymer dispersions of components A and B in such a way that coagulation is avoided. Preferably, the components A and B have no opposite surface charges in the inserted state. This avoids coagulation in step (b). The surface charges of components A and B can be controlled by charges in the polymer itself, optionally by varying the pH via protonation or proton elimination, or by using corresponding charged or uncharged emulsifiers.

The weight-average particle diameter of component B is preferably from 25 to 150 nm, in particular from 35 to 90 nm. The weight-average particle diameter of component A is preferably from 100 to 900 nm, in particular from 150 to 500 nm.

By using weight-average particle diameters of components A and B within the size and quantity ratios according to the invention, good properties with respect to the inhibition of the formation on limescale deposits are achieved, while at the same time good processability of the film-forming compositions. For example, use in paints becomes possible.

Without wishing to be limited, there is the notion that by using the mixtures according to the invention during film formation a favorable structure of the surface is formed, which is a prerequisite for the formation of the charge structure according to the invention. The favorable structure is in particular by more or less isolated and relatively large dispersion particles of the component A, which are nevertheless only slightly separated from each other, characterized. The relatively large dispersion particles of component A are separated from each other in the polymer film by the filmed small particles.

Preferably, the particle size distribution of the dispersions used in the present invention is narrow. This results in a particularly uniform and effective structure. The polymer dispersions of components A and B are preferably obtainable by free-radically initiated emulsion polymerization, in particular emulsion polymerization in the aqueous phase.

The implementation of free-radically initiated emulsion polymerizations of ethylenically unsaturated monomers in an aqueous medium has been described in detail and is therefore well known to the person skilled in the art, inter alia from Encyclopedia of Polymer Science and Engineering, Vol. 8, pages 659 et seq. (1987); D.C. Blackley, in High Polymer Latices, Vol. 1, pp. 35 et seq. (1966); H. Warson, The Applications of Synthetic Resin Emulsions, Chapter 5, pages 246 et seq. (1972); D. Diederich, Chemistry in Our Time 24, pages 135 to 142 (1990); Emulsion Polymerization, Interscience Publishers, New York (1965); DE-A 40 03 422 and dispersions of synthetic high polymers, F. Hölscher, Springer-Verlag, Berlin (1969). The free-radically induced aqueous emulsion polymerization reactions usually take place in such a way that the ethylenically unsaturated monomers are dispersed with the concomitant use of dispersants in the aqueous medium in the form of monomer droplets and polymerized by means of a free-radical polymerization initiator.

The preparation of the dispersions of components A and B used according to the invention can be carried out in each case by a single-stage or by an at least two-stage aqueous radical emulsion polymerization. In the context of the two-stage emulsion polymerization, a first polymer is first prepared in at least one step and a second polymer is prepared in at least one further step in the presence of the first polymer dispersion. A polymer dispersion is often referred to as a polymer dispersion. The terms "polymer dispersions" and "polymer latexes" are also synonymous. The resulting polymer dispersion preferably has a core-shell structure in which the core of the first polymer is formed and the shell of the second polymer. Corresponding methods are known to the person skilled in the art.

According to the invention, the components A and B differ with respect to the weight-average particle diameter and in their chemical composition.

The resulting local surface potential of the coatings according to the invention is significantly influenced by the charge state of the monomers incorporated in the polymer dispersion. It is obvious to a person skilled in the art that the surface charges of a polymer dispersion and thus the resulting local surface potential in the corresponding coating in the case of polymer particles having a core-shell structure are controlled by the surface charge of the outer layer.

In the context of the present invention, the following types of monomers are to be distinguished:

Permanently uncharged monomers (hereinafter referred to as type pu) which do not have a charged functional group in the pH range from 1 to 14. Permanent anionic monomers (hereinafter referred to as type pa), which are at least in a partial range from pH = 1 to pH = 14 have a negatively charged functional group such as COO ^"

Permanent cationic monomers (hereinafter referred to as type pk), which have a positively charged functional group, such as a quaternary N atom, at least in a partial range from pH = 1 to pH = 14. In the used state, uncharged, but after chemical reaction - in particular in the context of step (e) - at least in a partial range of pH = 1 to pH = 14 negatively charged monomers (hereinafter referred to as type and others)

In the inserted state uncharged, but after chemical reaction - in particular in the context of step (e) - at least in a partial range of pH = 1 to pH = 14 positively charged monomers (hereinafter referred to as type uk)

It will be apparent to those skilled in the art that the charge of an acidic or basic group will depend on the pH. The chemical reaction according to step (e) goes beyond the mere variation of the pH. Preferably, at least two monomers are copolymerized in each polymer dispersion in components A and B (hereinafter referred to as "comonomers"). It will be apparent to those skilled in the art that the monomers in the polymer dispersions and in the coatings are in substantially reacted (polymeric) form In the case of the finished polymer dispersions or coatings, reference to monomers is therefore to be understood as referring to the corresponding monomer building blocks.

Preferred monomers of the pu type are those based on acrylates. suitable

Monomers of the pu type are in particular esters based on

a 3 to 6 C-atoms, in particular a 3 or 4 C-containing α, β-monoethylenically unsaturated mono- or dicarboxylic acid, in particular acrylic acid, methacrylic acid, maleic acid, fumaric acid and itaconic acid and

an alkanol having 1 to 18 C atoms, preferably an alkanol having 1 to 8 C atoms and particularly preferably an alkanol having 1 to 4 C atoms, in particular methanol, ethanol, n-propanol, isopropanol, n-butanol , 2-methylpropanol-1, tert-butanol, n-pentanol, 3-methylbutanol-1, n-hexanol, 4-methylpentanol-1, n-heptanol, 5-methylhexanol-1, n-octanol, 6-methyl-heptanol -1, n-nonanol, 7-methyloctanol-1, n-decanol, 8-methylnonanol-1, n-dodecanol, 9-methyldecanol-1 or 2-ethylhexanol-1.

Preferably, acrylic, methacrylic, methyl, ethyl, n-butyl, isobutyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, ethylhexyl or dodecyl ester, fumaric and maleic acid dimethyl ester or di-n-butyl ester. Of course, mixtures of the aforementioned esters can be used.

In addition, suitable pu type monomers have at least two nonconjugated ethylenically unsaturated double bonds. Examples thereof are monomers containing two vinyl radicals, two vinylidene radical-containing monomers and two alkenyl radicals having monomers. Particularly advantageous are the diesters of dihydric alcohols with α, β-monoethylenically unsaturated monocarboxylic acids, among which acrylic and methacrylic acid are preferred. Examples of such two non-conjugated ethylenically unsaturated double bonds monomers are alkylene glycol diacrylates and dimethacrylates, such as ethylene glycol diacrylate, 1, 2-propylene glycol diacrylate, 1, 3-propylene glycol diacrylate, 1, 3-Butylenglykoldiacrylat, 1, 4- Butylene glycol diacrylates and ethylene glycol dimethacrylate, 1,2-propylene glycol dimethacrylate, 1,3-propylene glycol di-methacrylate, 1,3-butylene glycol dimethacrylate, 1,4-butylene glycol dimethacrylate and divinylbenzene, vinyl methacrylate, vinyl acrylate, allyl methacrylate, allyl acrylate, diallyl maleate, diallyl fumarate, methylenebisacrylamide, Cyclopentadienyl acrylate, triallyl cyanurate or triallyl isocyanurate. Of course, mixtures of the aforementioned compounds can be used.

Suitable monomers of the pu type are in particular 3 to 6 carbon atoms having α, β-monoethylenically unsaturated amides of mono- or dicarboxylic acids such as in particular amides of acrylic acid, methacrylic acid, maleic acid, fumaric acid or itaconic acid or acrylamide or methacrylamide or their mixtures.

In addition, preference is given to the following α, β-ethylenically unsaturated compounds as monomers of the pu type: vinylaromatic monomers, preferably styrene, α-methylstyrene, o-chlorostyrene or vinyltoluenes, vinyl halides, such as vinyl chloride or vinylidene chloride, esters of vinyl alcohol and 1 to Monocarboxylic acids having 18 carbon atoms, such as vinyl acetate, vinyl propionate, vinyl n-butyrate, vinyl laurate and vinyl steate, nitriles of α, β-mono- or diethylenically unsaturated carboxylic acids, such as acrylonitrile, methacrylonitrile, fumaronitrile, maleic acid dinitrile and 4-8 C atoms having conjugated dienes, such as 1, 3-butadiene and isoprene, moreover, N-vinylpyrrolidone, 2-vinyl-pyridine, 4-vinylpyridine, 2-vinylimidazole, 2- (N, N-dimethylamino) ethyl acrylate, 2- ( N, N-dimethylamino) ethyl methacrylate, 2- (N, N-diethylamino) ethyl acrylate, 2- (N, N-diethylamino) ethyl methacrylate, 2- (N-tert-butylamino) ethyl methacrylate, N- (3-N ' , N'-dimethyl-aminopropyl) methacrylamide or 2- (1-lm idazolin-2-onyl) ethyl methacrylate.

Other suitable monomers of the pu type have at least one hydroxyl, N-methylol or carbonyl group. Also of particular importance in this connection are the methacrylic acid and acrylic acid C 1 -C 8 -hydroxyalkyl esters, such as n-hydroxyethyl, n-hydroxypropyl or n-hydroxybutyl acrylate and methacrylate, and also compounds such as diacetoneacrylamide and acetylacetoxyethyl acrylate or methacrylate , Of course, mixtures of the aforementioned monomers can be used. Suitable monomers of the type pa are, in particular, α, β-monoethylenically unsaturated mono- or dicarboxylic acids having 3 to 6 C atoms, in particular acrylic acid, methacrylic acid, maleic acid, fumaric acid or itaconic acid. Suitable monomers of the type pa are also in particular vinylsulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, styrenesulfonic acid and their water-soluble salts. Of course, mixtures of the aforementioned monomers can be used. It is known to the person skilled in the art that the acid groups are in equilibrium with the deprotonated anionic form. The higher the pH, the higher the proportion of the deprotonated anionic form.

It is preferred if the polymer dispersions used in the process according to the invention in the context of component A or in the context of component B have such functional groups which are converted in step (e) such that a charge-structured surface is formed.

Preferred monomers of the pk type are, in particular, those which are cationically charged in the entire range from pH = 1 to pH = 14. Particularly preferred is quaternized 2-dimethylaminoethyl acrylate methyl chloride. Preference is given to all α, β-ethylenically unsaturated compounds having a carboxyl group which has been esterified with a protective group which can be eliminated by acids, bases or temperature, preferably under mild conditions. As protecting groups, e.g. the methyl esters, benzyl esters and allyl esters are used. In addition, ureido (meth) acrylate can be used. Preferred monomers of the type inter alia are in particular α, β-ethylenically unsaturated compounds having a carboxy group which is esterified with a tert-butyl group, in particular tert-butyl acrylate and tert-butyl methacrylate.

Preferred monomers of the type uk are α, β-ethylenically unsaturated compounds which contain an epoxide group as functional group, in particular acrylates with epoxide groups, more preferably glycidyl acrylate and / or glycidyl methacrylate.

Preferred polymer dispersions of components A and B each comprise at least two comonomers. It is preferred if at least one comonomer is of the pu type. At least one further comonomer is preferably selected such that either component A or component B is permanently charged, ie at least one comonomer of the polymer dispersions A or B is of the type pk or pa. If one of the components A or B is permanently charged, in particular comprises comonomers of the type pu and pa or pu and pk, then it is preferred that the in each case other component B or A comprises the comonomers pu and uk or pu and others, so that a charge-structured coating is formed after the chemical conversion of the monomers of the type ua or uk, but on the other hand during the mixing of the two components A and B no opposite surface charges are present. In a first particularly preferred embodiment I, either component A or component B comprises comonomers of the type pu and pk and at the same time the respective other component B or A comprises comonomers of the type pu and ao.

In a second particularly preferred embodiment II, either component A or component B comprises comonomers of the type pu and pa and at the same time the respective other component B or A comprises comonomers of the type pu and uk.

The aforementioned monomers of the type ua and uk have in common their property that functional groups charged in the coating by the subsequent reaction in the context of step (e) are produced in the coating. As a result, a surface charge is generated in the respective spatial area, which is preferably opposite to the charge in the region of the respective other component. For this, it is necessary that the corresponding functional groups be present either in component A or in component B, but not simultaneously in A and B in equal or similar amounts.

Methods for the preparation of the polymer dispersions of components A and B used according to the invention by aqueous free-radical emulsion polymerization are known to the person skilled in the art. For example, in each case at least a subset of the monomers can be initially charged in the aqueous reaction medium and any residual amount added to the aqueous reaction medium, after initiation of the free-radical polymerization reaction, batchwise in one portion, batchwise in several portions and continuously with constant or varying flow rates. However, it is also possible to initially introduce in the aqueous reaction medium at least a portion of the free-radical polymerization initiator, and the resulting aqueous reaction medium to polymerization temperature to heat and at this temperature, the monomers to the aqueous reaction medium discontinuously in one portion, discontinuously in several portions and continuously add with constant or changing flow rates.

Particularly advantageously, the monomers are added to the aqueous reaction medium in the form of a mixture. Advantageously, the addition of the monomers takes place in the form of an aqueous monomer emulsion. In a further, at least two-stage embodiment, in the presence of a first polymer, the further monomers are advantageously added to the aqueous reaction medium continuously in one or more portions with constant or varying flow rates. Particularly advantageously, the monomers are added to the aqueous reaction medium in the form of a mixture. Advantageously, the addition of the monomers takes place in the form of an aqueous monomer emulsion.

Usually, in the preparation of suitable polymer dispersions of components A and B, dispersants are also used which keep both the monomer droplets and the polymer particles formed dispersed in the aqueous medium and thus ensure the stability of the aqueous polymer dispersion produced. Suitable dispersants are both the protective colloids commonly used to carry out free-radical aqueous emulsion polymerizations and emulsifiers.

Suitable protective colloids are, for example, polyvinyl alcohols, polyalkylene glycols, alkali metal salts of polyacrylic acids and polymethacrylic acids, gelatin derivatives or acrylic acid, methacrylic acid, maleic anhydride, 2-acrylamido-2-methylpropanesulfonic acid and / or 4-styrenesulfonic acid-containing copolymers and their alkali metal salts but also N-vinylpyrrolidone, N-vinylpyrrolidone, Vinylcaprolactam, N-vinylcarbazole, 1 - vinylimidazole, 2-vinylimidazole, 2-vinylpyridine, 4-vinylpyridine, acrylamide, methacrylamide, acrylates containing amine groups, methacrylates, acrylamides and / or methacrylamides containing homopolymers and copolymers. A detailed description of other suitable protective colloids can be found in Houben-Weyl, Methods of Organic Chemistry, Volume XIV / 1, Macromolecular substances, Georg-Thieme-Verlag, Stuttgart, 1961, pages 41 1 to 420. Of course, mixtures of protective colloids and / or emulsifiers can be used. Frequently, dispersants used are exclusively emulsifiers whose relative molecular weights, in contrast to the protective colloids, are usually below 1000. They may be anionic, cationic or nonionic in nature. Of course, in the case of the use of mixtures of surfactants, the individual components must be compatible with each other, which can be checked in case of doubt by hand on fewer preliminary tests. In general, anionic emulsifiers are compatible with each other and with nonionic emulsifiers. The same applies to cationic emulsifiers, while anionic and cationic emulsifiers are usually incompatible with each other. An overview of suitable emulsifiers can be found in Houben-Weyl, Methods of Organic Chemistry, Volume XIV / 1, Macromolecular substances, Georg-Thieme-Verlag, Stuttgart, 1961, pages 192 to 208. Preferably, however, are preferably used as dispersants emulsifiers.

Common nonionic emulsifiers are, for example, ethoxylated mono-, di- and tri-alkylphenols (EO degree: 3 to 50, alkyl radical: C ₄ to C 12) and also ethoxylated fatty alcohols (EO degree: 3 to 80, alkyl radical: Cs to C36). Examples are the Lutensol ^® A grades (C ₂ C ₄ fatty alcohol EO units: 3 to 8), Lutensol ^® AO-marks (C13C15-oxo-alcohol ethoxylates, EO units: 3 to 30), Lutensol ^® AT (CieCis ethoxylate fatty alcohol, EO: 1 1 to 80) brands Lutensol ON ^® brands (Cio-oxo alcohol ethoxylates, EO degree: 3 to 1: 1), and ^® Lutensol tO brands (ds-oxo alcohol ethoxylates, EO grade: 3 to 20) from BASF SE. Typical anionic emulsifiers include alkali metal and ammonium salts of alkyl sulfates (alkyl radical: Cs to C12), ethoxylated sulfuric acid monoesters of alkanols (EO units: 4 to 30, alkyl radical: C12 to C ₈₎ and ethoxylated alkylphenols (EO units: 3 to 50, alkyl radical: C ₄ to C 12), of alkyl sulfonic acids (alkyl radical: C 12 to C 18) and of alkylaryl sulfonic acids (alkyl radical: C 9 to C 18).

Further anionic emulsifiers further compounds of the general formula (I)

wherein R ¹ and R ² hydrogen atoms or C ₄ - to C2 ₄ alkyl and not simultaneously hydrogen atoms, and may be M ¹ and M ² alkali metal ions and / or ammonium ions, have proven suitable. In the general formula (I), R ¹ and R ^{2 are} preferably linear or branched alkyl radicals having 6 to 18 C atoms, in particular having 6, 12 and 16 C atoms or hydrogen, where R ¹ and R ^{2 are} not both simultaneously H and Atoms are. M ¹ and M ² are preferably sodium, potassium or ammonium, with sodium being particularly preferred. Particularly advantageous are compounds (I) in which M ¹ and M ^{2 are} sodium, R ^{1 is} a branched alkyl radical having 12 C atoms and R ^{2 is} an H atom or R ¹ . Frequently, technical mixtures are used which have a proportion of 50 to 90 wt .-% of the monoalkylated product, such as Dowfax ^® 2A1 (trademark of the Dow Chemical Company). The compounds (I) are well known, for example, from US-A 4,269,749, and commercially available.

Suitable cationic emulsifiers are generally primary, secondary, tertiary or quaternary ammonium salts containing C 6 -C 18 -alkyl, -alkylaryl or heterocyclic radicals, alkanolammonium salts, pyridinium salts, imidazolinium salts, oxazolinium salts, morpholinium salts, thiazolinium salts and salts of amines. noxides, quinolinium salts, isoquinolinium salts, tropylium salts, sulfonium salts and phosphonium salts. Examples include dodecylammonium acetate or the corresponding sulfate, the sulfates or acetates of the various 2- (N, N, N-trimethyl ammonium) ethylparaffinsäureester, N-cetylpyridinium sulfate, N-laurylpyridinium and N-cetyl-N, N, N-trimethylammonium sulfate, N-dodecyl-N, N, N-trimethylammonium sulfate, N-octyl-N, N, N-trimethylammonium sulfate, N, N-distearyl-N, N-dimethylammonium sulfate and the gemini-surfactant N, N '- ( lauryl) ethylendiamindisulfat, ethoxylated tallow alkyl-N-methyl ammonium sulfate and ethoxylated oleylamine (for example Uniperol.RTM ^® AC from. BASF AG, about 12 ethylene oxide). Numerous other examples can be found in H. Stäche, Tensid-Taschenbuch, Carl-Hanser-Verlag, Munich, Vienna, 1981 and in McCutcheon's, Emulsifiers & Detergents, MC Publishing Company, Glen Rock, 1989. It is favorable if the anionic counterparts groups are as low as possible nucleophilic, such as perchlorate, sulfate, phosphate, nitrate and Carboxylates, such as acetate, trifluoroacetate, trichloroacetate, propionate, oxalate, citrate, benzoate, and conjugated anions of organo-sulfonic acids, such as methyl sulfonate, trifluoromethyl sulfonate and para-toluenesulfonate, tetrafluoroborate, tetraphenylborate, tetrakis (pentafluoro-) phenyl) borate, tetrakis [bis (3,5-trifluoromethyl) phenyl] borate, hexafluorophosphate, hexafluoroarsenate or hexafluoroantimonate.

The emulsifiers preferably used as dispersants are advantageously in a total amount of> 0.005 and <10 wt .-%, preferably> 0.01 and <5 wt .-%, in particular> 0.1 and <3 wt .-%, respectively based on the total amount of monomers used.

The total amount of the protective colloids used as dispersing agents in addition to or instead of the emulsifiers is often> 0.1 and <10% by weight and frequently> 0.2 and <7% by weight, in each case based on the total amount of monomer.

However, preference is given to using anionic and / or nonionic emulsifiers and particularly preferably anionic emulsifiers as dispersants. The release of the free-radically initiated aqueous emulsion polymerization takes place by means of a free-radical polymerization initiator (free-radical initiator). In principle, these can be both peroxides and azo compounds. Of course, redox initiator systems come into consideration. As peroxides may in principle inorganic peroxides, such as hydrogen peroxide or peroxodisulfates, such as the mono- or di-alkali metal or ammonium salts of peroxodisulfuric, such as their mono- and di-sodium, potassium or ammonium salts or organic peroxides, such as alkyl hydroperoxides, for example tert-butyl, p-menthyl or cumyl hydroperoxide, and also dialkyl or diaryl peroxides, such as di-tert-butyl or di-cumyl peroxide. As an azo compound substantially 2,2 - azobis (isobutyronitrile), ^2,2'-azobis (2,4-dimethylvaleronitrile), and ^2,2'-azobis (amidino propyl) dihydrochloride (AIBA, corresponding to V-50 from Wako Chemicals ) Use. Suitable oxidizing agents for redox initiator systems are essentially the abovementioned peroxides. Suitable reducing agents may be sulfur compounds having a low oxidation state, such as alkali metal sulphites, for example potassium and / or sodium sulphite, alkali hydrogen sulphites, for example potassium and / or sodium hydrogen sulphite, alkali metal bisulphites, for example potassium and / or sodium metabisulphite. sulfite, formaldehyde sulfoxylates, for example potassium and / or sodium formaldehyde sulfoxylate, alkali metal salts, especially potassium and / or sodium salts, aliphatic sulfinic acids and alkali metal hydrogensulfides, for example potassium and / or sodium hydrogen sulfide, salts of polyvalent metals, such as iron (II ) sulfate, iron (II) ammonium sulfate, iron (II) phosphate, endiols, such as dihydroxymaleic acid, benzoin and / or ascorbic acid, and reducing saccharides, such as sorbose, glucose, fructose and / or dihydroxyacetone , In general, the amount of the radical initiator used, based on the total amount of monomers, 0.01 to 5 wt .-%, preferably 0.1 to 3 wt .-% and particularly preferably 0.2 to 1, 5 wt .-%.

Preferably, the total amount of the radical initiator is initially charged in the aqueous reaction medium. However, it is also possible, if appropriate, to initially introduce only a partial amount of the free-radical initiator in the aqueous reaction medium and then to add continuously or discontinuously during the free radical emulsion polymerization the total amount or the residual amount remaining if appropriate in accordance with consumption.

The reaction temperature for the free-radical aqueous emulsion polymerization is the entire range from 0 to 170 ° C into consideration. As a rule, temperatures of 50 to 120 ° C, often 60 to 1 10 ° C and often 70 to 100 ° C are used. The free-radical aqueous emulsion polymerization can be carried out at a pressure of less than or equal to 1 bar (absolute), so that the polymerization temperature can exceed 100 ° C. and can be up to 170 ° C. Preferably, volatile monomers such as 2-methyl-1-butene-1, 3-methylbutene-1, 2-methylbutene-2, butadiene, butene-2, 2-methylpropene, propene, ethylene or vinyl chloride are polymerized under elevated pressure. The pressure may be 1, 2, 1, 5, 2, 5, 10, 15, 50, 100 bar or even higher values. If emulsion polymerizations are carried out under reduced pressure, pressures of 950 mbar, often 900 mbar and often 850 mbar (absolute) are set. The free-radical aqueous emulsion polymerization is advantageously carried out at 1 atm (1:01 bar absolute) under an inert gas atmosphere, such as under nitrogen or argon.

The aqueous reaction medium may in principle also comprise, in minor amounts, water-soluble organic solvents, such as, for example, methanol, ethanol, isopropanol, butanols, pentanols, but also acetone, etc. This is preferred Process for the preparation of the polymer dispersions of components A and B, however, carried out in the absence of such solvents.

In addition to the abovementioned components, it is also possible optionally to use free-radical chain compounds in order to reduce or control the molecular weight of the polymers obtainable by the polymerization. These are essentially aliphatic and / or araliphatic halogen compounds, such as, for example, n-butyl chloride, n-butyl bromide, n-butyl iodide, methylene chloride, ethylenedichloride, chloroform, bromoform, bromotrichloromethane, dibromodichloromethane, carbon tetrachloride, carbon tetrabromide, benzyl chloride, benzyl bromide, organic Thio compounds, such as primary, secondary or tertiary aliphatic thiols, such as ethanethiol, n-propanethiol, 2-propanethiol, n-butanethiol, 2-butanethiol, 2-methyl-2-propanethiol, n-pentanethiol, 2-pentanethiol, 3-pentanethiol , 2-methyl-2-butanethiol, 3-methyl-2-butanethiol, n-hexanethiol, 2-hexanethiol, 3-hexanethiol, 2-methyl-2-pentanethiol, 3-methyl-2-pentanethiol, 4-methyl-2 pentanethiol, 2-methyl-3-pentanethiol, 3-methyl-3-pentanethiol, 2-ethylbutanethiol, 2-ethyl-2-butanethiol, n-heptanethiol and its isomeric compounds, n-octanethiol and its isomeric compounds, n-nonanethiol and its isomeric compounds, n-decanethiol and its isomers Compounds, n-undecanethiol and its isomeric compounds, n-dodecanethiol and its isomeric compounds, n-tridecanethiol and its isomeric compounds, substituted thiols, such as, for example, 2-hydroxyethanethiol, aromatic thiols, such as benzenethiol, ortho, meta, or para Methylbenzenethiol, as well as all other described in Polymerhandbook 3 ^rd edtiti- on, 1989, J. Brandrup and EH Immergut, John Weley & Sons, Section II, pages 133 to 141, but also aliphatic and / or aromatic aldehydes, such as Acetaldeyhd, propionaldehyde and / or benzaldehyde, unsaturated fatty acids such as oleic acid, dienes with non-conjugated double bonds, such as divinylmethane or vinylcyclohexane or hydrocarbons with easily abstractable hydrogen atoms, such as toluene, are used. However, it is also possible to use mixtures of non-interfering aforementioned radical chain-transferring compounds.

The total amount of radical chain transferring compounds optionally used in the preparation of the polymer dispersions, based on the total amount of monomers, is generally <5% by weight, often <3% by weight and frequently <1% by weight. It is advantageous if a partial or total amount of the optionally used radical chain-transmitting compound is fed to the reaction medium before the initiation of the free-radical polymerization. In addition, a partial or total amount of the radical chain-transferring compound may advantageously also be added to the aqueous reaction medium together with the monomers during the polymerization.

Optionally, the free-radically initiated aqueous emulsion polymerization in the presence of a polymer seed, for example in the presence of 0.01 to 3 wt .-%, often from 0.02 to 2 wt .-% and often from 0.04 to 1, 5 wt. % of a polymer seed, in each case based on the total amount of monomers.

A polymer seed is used in particular when the particle size of the polymer particles to be prepared by free-radical aqueous emulsion polymerization is to be specifically adjusted (see, for example, US Pat. No. 2,520,959 and US Pat. No. 3,397,165). In particular, a polymer seed is used whose polymer seed particles have a narrow particle size distribution and weight-average diameters D _w <100 nm, frequently> 5 nm to <50 nm and often> 15 nm to <35 nm. Usually, the polymer seed is used in the form of an aqueous polymer dispersion. The aforementioned amounts are based on the polymer solids content of the aqueous Polymersaatdispersion; they are therefore given as parts by weight of polymer seed solids, based on the total amount of monomers. If a polymer seed is used, it is advantageous to use a foreign polymer seed. In contrast to a so-called in situ polymer seed, which is prepared prior to the actual emulsion polymerization in the reaction vessel and which has the same monomeric composition as the polymer prepared by the subsequent free-radically initiated aqueous emulsion polymerization, a foreign polymer seed is understood to mean a polymer seed which in one Separate reaction step was prepared and their monomeric composition of the polymer prepared by the free-radically initiated aqueous emulsion polymerization is different, but this means nothing else than that used for the preparation of Fremdpolymersaat and for the preparation of the aqueous polymer dispersion different monomers or monomer mixtures of different composition become. The production of a foreign polymer seed is subject to man and usually carried out such that a relatively small amount of monomers and a relatively large amount of emulsifiers in a reaction vessel are introduced and at reaction temperature, a sufficient amount of polymerization initiator is added.

Preference is given to using polymer foreign seed with a glass transition temperature> 50 ° C., frequently> 60 ° C. or> 70 ° C. and often> 80 ° C. or> 90 ° C. Particularly preferred is a polystyrene or a polymethyl methacrylate polymer seed. The total amount of foreign polymer seed may be presented in the reaction vessel prior to the beginning of the addition of the monomers used to prepare the polymer dispersions of components A and B. However, it is also possible to introduce only a subset of the foreign polymer seed prior to the beginning of the addition of the monomers in the reaction vessel and to add the remaining amount during the polymerization. If necessary, however, it is also possible to add the total amount of polymer seed in the course of the polymerization. Preferably, the total amount of Fremdpolymersaat is submitted before the beginning of the addition of the monomers in the reaction vessel. Aqueous polymer dispersions preferred for components A and B usually have a polymer solids content of> 10 and <80% by weight, preferably> 15 and <70% by weight and often> 20 and <50% by weight, in each case based on the aqueous Polymer dispersion, on. The polymer solids contents of components A and B are particularly preferably from 15 to 40% by weight.

Frequently in the aqueous polymer dispersions obtained, the residual contents of unreacted monomers and other low-boiling compounds by the skilled person also known chemical and / or physical methods [see, for example, EP-A 771328, DE-A 196 24 299, DE-A 196 21 027, DE-A 197 41 184, DE-A 197 41 187, DE-A 198 05 122, DE-A 198 28 183, DE-A 198 39 199, DE-A 198 40 586 and 198 47 1 15] reduced.

In the context of the process according to the invention, the polymer dispersions from step (a) and optionally further components are mixed according to step (b), the weight ratio of component A to component B being 95: 5 to 60: 40, based on the solids content. Preferably, the weight Ratio of the components A to B in the mixture thus obtained from 90 to 10 to 70 to 30 (each based on the solids content).

As methods for mixing the polymer dispersions, it is possible to use in principle all methods of mixing dispersions which are widely known to the person skilled in the art, mixing in particular being preferred with stirring.

In principle, all other additives and active substances and auxiliaries known to the person skilled in the art may be considered as further components. Corresponding formulations for coatings (topcoat) are known to the person skilled in the art, for example, from R. Schwalm: "UV Coatings: basics, recent developments and new applications", Elsevier (2007), in particular pages 140 to 145. Formulations for paints are One skilled in the art, for example, from R. Baumstark, M. Schwartz: "Dispersions for architectural paints: acrylate systems in theory and practice", Curt R. Vincentz Verlag (2001), in particular pages 52 to 54 and 217 to 218, known.

According to step (c) of the process according to the invention, the mixture of step (b) is applied to a surface, preferably a substrate. Suitable substrates are in particular plastics, steel, ceramics, glass and concrete.

The term surface includes any suitable surface-having base for the coating. In a first preferred embodiment, the application is carried out on a substrate. In a second preferred embodiment, the application takes place on a surface in the construction sector, in particular a wall, wherein the application takes place within the scope of a formulation, in particular as a facade paint.

The application can be carried out by customary application and / or coating methods known to the person skilled in the art. Suitable methods are, for example, doctoring, brushing, dip-coating or spray-coating. Criteria for the choice of a suitable application method and the determination of the specific parameters of the application are known per se to the person skilled in the art and depend in a known manner on the type and shape of the surface and the specific properties of the mixture to be applied.

In step (d) of the process according to the invention, the solidification of the mixture from step (c) takes place to form a coating. The term "solidification" In this case, the formation of a solid, ie coherent structure, which is already to be regarded as a coating, is not to be understood as meaning that liquid residual components in the coating are excluded.The solidification of the mixture takes place in the presence of the substrate with at least partial removal, especially extensive removal of the liquid phase ("drying"). In this case, it is preferred if the particles of the components A and B film, ie film under interparticle crosslinking. In particular, the filming of the particles of component B with one another is preferred. Corresponding methods are known to the person skilled in the art.

The solidification of the mixture according to step (d) can be carried out in particular at room temperature or at elevated temperature, for example at 25 ° C to 100 ° C. Preferably, the drying is at room temperature. The pressure applied during drying can vary over a wide range and correlates in a known manner with the rate of drying. Likewise, the water content of the ambient air can vary. Usually it is dried in air. The duration of the drying may vary over a wide period of time depending on the aforementioned parameters, for example from 10 minutes to 24 hours. The duration of the drying also depends on the layer thickness.

Step (d) may proceed smoothly in step (e), i. H. Step (d) may not necessarily have resulted in complete drying before step (e) is performed. By definition, however, the coating resulting from step (d) must have at least one coherent solid structure.

In the context of the process according to the invention, the further chemical conversion of the coating takes place within the scope of step (e), with the result that a periodic structure of the surface potential is obtained.

In a preferred embodiment, in the context of step (e), the change in the surface charge of one of the components A or B from neutral to positive or from neutral to negative. The type and conditions of the chemical reaction according to step (e) are dependent on the type of monomers used, in particular of which was used under the conditions of step (e) reactive type monomer (ua or uk). In a preferred embodiment, the further chemical reaction according to step (e) takes place under the action of an elevated temperature and elimination of a molecule. The prerequisite for this is the use of a corresponding monomer of the type ua or uk (in particular type ua), which is thermally convertible into a charged monomer unit.

Particularly preferred is the elimination of isobutene or CO2. In a very preferred embodiment, one of the dispersions A or B comprises tert-butyl acrylate as comonomer. In this embodiment, the removal of isobutene by applying an elevated temperature of 150 to 300 ° C, in particular from 180 ° C to 250 ° C. The time varies with the temperature and is from 10 minutes to 24 hours. If other monomers than tert-butyl acrylate are used as monomer of the type ua or uk, which can be converted thermally into a monomer unit with charged functional group, the skilled person adjusts the temperature ranges and time periods suitable for the cleavage by appropriate preliminary experiments.

In a further preferred embodiment, the further chemical reaction according to step (e) takes place under the action of a chemical compound, in particular a nucleophilic compound, wherein the further chemical reaction particularly preferably comprises the opening of epoxide groups. The prerequisite for this is the use of a corresponding type of monomer ua or uk as described above (in particular type uk).

The further reaction by the action of a chemical compound can in principle be carried out by means of any form of contacting with the chemical compound. Preferably, the further chemical reaction is carried out by spraying the solidified coating with the chemical compound.

When uk monomers are used, the appropriate substrate or polymer film is preferably (preferably sprayed) at room temperature with a suitable nucleophile during step (e). For example, the reaction between amines and epoxide groups takes place very rapidly and quantitatively even at room temperature. The epoxide ring is opened by the amine and an amine noalcohol formed. Depending on the pH of the surface of the film, the resulting tertiary amine is protonated and thus cationically charged.

In principle, the charges resulting from step (e) outweigh the few opposing charges which originate from superficially adsorbed charged emulsifiers or protective colloids or copolymerized charged groups from the initiator.

A further subject of the present invention are the coatings obtainable according to the process according to the invention and the use of the coatings according to the invention for the reduction of deposit formation, in particular for the reduction of quench deposits on surfaces which come into contact with water. Moreover, the present invention relates to the use of coatings having a periodic structure of surface potential to reduce deposit formation. Preferably, the coatings are obtained by a process comprising the steps of:

(a) providing at least one first polymer dispersion as component A and at least one second polymer dispersion as component B, wherein the components A and B differ in their chemical composition,

(b) mixing the polymer dispersions from step (a) and optionally further components, wherein the weight ratio of component A to component B relative to the solids content is from 95: 5 to 60: 40,

(c) applying the mixture from step (b) to a surface, preferably a substrate,

(d) solidifying the mixture of step (c) to obtain a coating, and

(e) optionally further chemical reaction of the coating to obtain a periodic structure of the surface potential, wherein the ratio of the weight average particle diameter of component A to that of component B is from 3: 1 to 15: 1, the weight average particle diameter of component A is from 75 to 1000 nm and the weight average particle diameter of the component B is from 10 to 200 nm. Examples Example 1 :

In a 2 liter polymerization reactor with paddle stirrer and

Heating / cooling device, a mixture of 450.0 g of deionized water and 17.23 g of feed 1 and under nitrogen atmosphere at 80 ° C was heated. For this purpose, after stirring for 5 minutes at a given temperature, 9.30 g of feed 3 were added. After 15 minutes, feed 1 and feed 3 were started. Feed 1 was metered in evenly over 2 hours. Feed 3 was metered in evenly over 4 hours. Feed 1 was an aqueous emulsion prepared from 448.50 g of deionized water, 0.75 g of Lipamin® OK (a 37% solution of an oxyethylated fatty amine derivative), 238.50 g of n-hexane.

Butyl acrylate and 1, 50 g of allyl methacrylate. Feed 3 was a solution of 90.00 g deionized water and 3.00 g Azostarter V-50 (2-2 ^' azobis (2-methylpropionamidine) dihydrochloride, from Wako). After the end of feed 1, feed 2 was started after 30 minutes and metered in uniformly over one hour. Feed 2 was an aqueous emulsion prepared from 225.00 g of deionized water, 0.75 g of Lipamin® OK (a 37% solution of an oxyethylated fatty amine derivative, trademark of BASF SE) and 60.00 g of tert-butyl acrylate. After the end of feeds 2 and 3, the mixture was stirred at 80 ° C. for a further 60 minutes and the reaction mixture was subsequently cooled to room temperature. The aqueous polymer dispersion obtained had a solids content of 19.1% by weight (weight-average particle diameter 380 nm).

Example 2:

In a 2 liter polymerization reactor with paddle stirrer and

A mixture of 450.0 g deionized water and 60.00 g Lipamin® OK (a 37% solution of an oxyethylated fatty amine derivative) was heated to 85 ° C under a nitrogen atmosphere under heating / cooling. For this purpose, the partial amount of 106.20 g of feed 1 was added. For this purpose, the portion of 9.30 g of feed 2 was added after stirring for 5 minutes at a given temperature. After 15 minutes, feed 1 and feed 2 were started. Feed 1 was added uniformly over 3 hours. Feed 2 was metered in evenly over 4 hours. Feed 1 was an aqueous emulsion prepared from 747.00 g deionized water, 15.00 g Lipamin® OK (a 37% solution of an oxyethylated fatty amine derivative), 149.25 g styrene, 149.25 g, n-butyl acrylate and 1, 50 g of allyl methacrylate. Feed 2 was a solution of 90.00 g deionized water and 3.00 g azo starter V-50. After the end of feed 2, the mixture was stirred at 85 ° C. for a further 60 minutes and the reaction mixture was then cooled to room temperature. cools. The aqueous polymer dispersion obtained had a solids content of 19.5% by weight (weight-average particle diameter 53 nm).

Example 3:

In a 2 liter polymerization reactor with paddle stirrer and

A mixture of 450.0 g deionized water and 60.00 g Lipamin® OK (a 37% solution of an oxyethylated fatty amine derivative) was heated to 85 ° C under a nitrogen atmosphere under heating / cooling. For this purpose, 78.07 g of feed 1 was added at a predetermined temperature. After stirring for 5 minutes, 28.88 g of feed 3 were added. After 15 minutes, feed 1 and feed 3 were started. Feed 1 was metered in evenly over 2 hours. Feed 3 was metered in evenly over 4 hours. Feed 1 was an aqueous emulsion prepared from 525.75 g of deionized water, 15.00 g of Lipamin® OK (a 37% solution of an oxyethylated fatty amine derivative), 238.50 g of n-butyl acrylate and 1.50 g of allyl methacrylate. Feed 3 was a solution of 90.00 g deionized water and 3.00 g Azostarter V-50. After the end of feed 1, feed 2 was started after 30 minutes and metered in uniformly over one hour. Feed 2 was an aqueous emulsion prepared from 225.00 g of deionized water, 3.75 g of Lipamin® OK (a 37% solution of an oxyethylated fatty amine derivative, trademark of BASF SE) and 60.00 g of tert-butyl acrylate. After the end of feeds 2 and 3, the mixture was stirred at 85 ° C. for a further 60 minutes and the reaction mixture was subsequently cooled to room temperature. The aqueous polymer dispersion obtained had a solids content of 19.6% by weight (weight-average particle diameter 44 nm). Example 4:

In a 2 liter polymerization reactor with paddle stirrer and

Heating / cooling device was heated to 85 ° C 450.0 g of deionized water under a nitrogen atmosphere. For this purpose, the partial amount of 24.35 g of feed 1 was added. For this purpose, after stirring for 5 minutes at a given temperature, the partial amount of 9.30 g of feed 2 was added. After 15 minutes, feed 1 and feed 2 were started. Feed 1 was added uniformly over 3 hours. Feed 2 was metered in evenly over 4 hours. Feed 1 was an aqueous emulsion prepared from 672.75 g of deionized water, 1.13 g of Lipamin® OK (a 37% solution of an o-methylated fatty amine derivative), 149.25 g of styrene, 149.25 g of n-butyl acrylate and 1.50 g of allyl methacrylate. Feed 2 was a solution of 90.00 g deionized water and 3.00 g Azostarter V-50. After the end of the feed 2 was stirred for a further 60 minutes at 85 ° C and the reaction mixture was then cooled to room temperature. The aqueous polymer dispersion obtained had a solids content of 19.1% by weight (weight-average particle diameter 395 nm).

Example 5:

In a 2 liter polymerization reactor with paddle stirrer and

A mixture of 450.0 g deionized water and 60.00 g Lipamin® OK (a 37% solution of an oxyethylated fatty amine derivative) was heated to 85 ° C under a nitrogen atmosphere under heating / cooling. For this purpose, the partial amount of 107.70 g of feed 1 was added. For this purpose, the portion of 9.30 g of feed 2 was added after stirring for 5 minutes at a given temperature. After 15 minutes, feed 1 and feed 2 were started. Feed 1 was added uniformly over 3 hours. Feed 2 was metered in evenly over 4 hours. Feed 1 was an aqueous emulsion prepared from 747.00 g deionized water, 15.00 g Lipamin® OK (a 37% solution of an oxyethylated fatty amine derivative), 238.50 g styrene, 75.00 g quaternized. 2- (dimethylaminoethyl acrylate Feed 2 was a solution of 90.00 g of deionized water and 3.00 g of Azostarter V-50 After the end of feed 2, the mixture was stirred at 85 ° C. for a further 60 minutes and the reaction mixture was then taken up in vacuo The aqueous polymer dispersion obtained had a solids content of 20.4% by weight (weight-average particle diameter 65 nm).

In a 2 liter polymerization reactor with paddle stirrer and

Heating / cooling device, a mixture of 450.0 g of deionized water and 60.00 g of Lipamin® OK (a 37% solution of an oxyethylated fatty amine derivative) was heated under nitrogen atmosphere to 85 ° C. For this purpose, the partial amount of 106.20 g of feed 1 was added. For this purpose, the portion of 9.30 g of feed 2 was added after stirring for 5 minutes at a given temperature. After 15 minutes, feed 1 and feed 2 were started. Feed 1 was added uniformly over 3 hours. Feed 2 was metered in evenly over 4 hours. Feed 1 was an aqueous emulsion prepared from 739.50 g of deionized water, 15.00 g of Lipamin® OK, 132.75 g of n-butyl acrylate, 132.75 g of styrene, and 37.50 g of quaternized 2- (dimethylaminoethyl acrylate). Methyl chloride and 4.50 g of allyl methacrylate. Feed 2 was a solution of 90.00 g deionized water and 3.00 g Azostarter V-50. After the end of the feed 2 was stirred for a further 60 minutes at 85 ° C and the reaction mixture was then cooled to room temperature. The aqueous polymer dispersion obtained had a solids content of 19% by weight (weight-average particle diameter 46 nm).

Example 7:

In a 2 liter polymerization reactor with paddle stirrer and

Heating / cooling device was heated to 80 ° C 375.00 g of deionized water under nitrogen atmosphere. For this purpose, the partial amount of 21, 09 g of feed 1 was added. For this purpose, the portion of 3.75 g of feed 2 was added after stirring for 5 minutes at a given temperature. After 15 minutes, feed 1 and feed 2 were started. Feed 1 and feed 2 were metered in evenly over 3 hours. Feed 1 was an aqueous emulsion prepared from 592.64 g deionized water, 1, 1 1 g of a 45 wt .-% aqueous solution of the sodium salt of a Ci2-substituted Biphenylethersulfonates (Dowfax ^® 2A1, trademark of Dow Chemical Company), 1 1 1, 88 g of n-butyl acrylate, 1 1 1, 88 g of styrene, 25.00 g of acrylic acid and 1, 25 g of allyl methacrylate. Feed 2 was 37.50 g of a 2% strength by weight aqueous solution of sodium peroxidisulfate. After the end of the feeds 1 and 2 was stirred for a further 30 minutes at 80 ° C and the reaction mixture was then cooled to room temperature. The aqueous polymer dispersion obtained had a solids content of 19.5% by weight (weight-average particle diameter 239 nm). Example 8:

In a 2 liter polymerization reactor with paddle stirrer and

Heating / cooling device, a mixture of 375.00 g of deionized water and 16.67 g Dowfax® 2A1 was heated to 80 ° C under a nitrogen atmosphere. For this purpose, the partial amount of 75.53 g of feed 1 was added. For this purpose, the portion of 3.75 g of feed 3 was added after stirring for 5 minutes at a given temperature. After 15 minutes, feed 1 and feed 3 were started. Feed 1 was metered in evenly over 2 hours. Feed 2 was added uniformly over 3 hours. Feed 1 was an aqueous emulsion prepared from 520.44 g deionized water, 4.89 g of a 45 wt .-% aqueous solution of the sodium salt of a Ci2-substituted Biphenylethersulfonates (Dowfax ^® 2A1), 199.00 g of n-butyl acrylate and 1 , 00 g of allyl methacrylate. Feed 3 was 37.50 g of a 2% strength by weight aqueous solution of sodium peroxidisulfate. After the end of the feed 1 was stirred for a further 30 minutes at 80 ° C and then feed 2 was added evenly in 30 minutes. Feed 2 was an aqueous emulsion prepared from 99.28 g of deionized water, 1, 22 g of a 45 wt .-% aqueous solution of the sodium salt of a Ci2-substituted Biphenylethersulfonates (Dowfax ^® 2A1), 25.00 g of methyl methacrylate and 25.00 g glycidyl methacrylate. After the end of feeds 2 and 3, the mixture was stirred at 80 ° C. for a further 30 minutes and the reaction mixture was subsequently cooled to room temperature. The aqueous polymer dispersion obtained had a solids content of 20.0% by weight (weight average particle diameter 80 nm).

Example 9:

In a 2 liter polymerization reactor with paddle stirrer and

Heating / cooling device was heated to 80 ° C 375.00 g of deionized water under nitrogen atmosphere. For this purpose, the partial amount of 16.95 g of feed 1 was added. For this purpose, the portion of 3.75 g of feed 3 was added after stirring for 5 minutes at a given temperature. After 15 minutes, feed 1 and feed 3 were started. Feed 1 was metered in evenly over 2 hours. Feed 2 was metered in uniformly over 3 hours. Feed 1 was an aqueous emulsion prepared from 475.83 g of deionized water,

2.22 g of a 45 wt .-% aqueous solution of the sodium salt of a C12 substituted Biphenylethersulfonates (Dowfax ^® 2A1), 199.00 g of n-butyl acrylate, and 1, 00 g of allyl methacrylate. Feed 3 was 37.50 g of a 2% by weight aqueous solution of sodium peroxydisulfate. After the end of feed 1, an additional 30 minutes were added

Stirred 80 ° C and then added feed 2 evenly over 30 minutes. Feed 2 was an aqueous emulsion prepared from 1 18.54 g of deionized water, 0.28 g of a 45 wt .-% aqueous solution of the sodium salt of a Ci2-substituted Biphenylethersulfonates (Dowfax ^® 2A), 25.00 g of methyl methacrylate and 25, 00 g of glycidyl methacrylate. After the end of feeds 2 and 3, the mixture was stirred at 80 ° C. for a further 30 minutes and the reaction mixture was subsequently cooled to room temperature. The aqueous polymer dispersion obtained had a solids content of 19.8% by weight (weight-average particle diameter 306 nm). Example 10: A mixture of 375.00 g of deionized water and 16.67 g of a 45% strength by weight aqueous solution of the sodium salt of a C 12 -substituted biphenyl ether sulfonate (Dowfax® 2A1) under a nitrogen atmosphere was placed in a 2 liter reactor with paddle stirrer and heating / cooling device heated to 80 ° C. For this purpose, the partial amount of 87.58 g of feed 1 was added. For this purpose, the portion of 3.75 g of feed 2 was added after stirring for 5 minutes at a given temperature. After 15 minutes, feed 1 and feed 2 were started. Feed 1 and feed 2 were metered in evenly over 3 hours. Feed 1 was an aqueous emulsion prepared from 619.72 g deionized water, 6.1 1 g of a 45 wt .-% aqueous solution of the sodium salt of a Ci2-substituted Biphenylethersulfonates (Dowfax ^® 2A1), 1 1 1, 88 g of n- Butyl acrylate, 1 1 1, 88 g of styrene, 25.00 g of acrylic acid and 1, 25 g of allyl methacrylate. Feed 2 was 37.50 g of a 2% by weight aqueous solution of sodium peroxodisulfate. After the end of feeds 1 and 2, the mixture was stirred at 80 ° C. for a further 30 minutes and the reaction mixture was subsequently cooled to room temperature. The aqueous polymer dispersion obtained had a solids content of 17.9% by weight (weight-average particle diameter 67 nm).

Subsequently, dispersion dispersions listed below were prepared from the dispersions of Examples 1 to 10. The dispersion mixtures were prepared in the following mixing ratio (parts by weight) based on the solids content by intensive stirring.

Blend 1: Dispersion from Example 1 and dispersion from Example 2 in a weight ratio based on the solids content Example 1 / Example 2 of 75 wt .-% / 25 wt .-%.

Blend 2: 90 wt.% Example 1/10 wt.% Example 2 Blend 3: 90 wt.% Example 4/10 wt.% Example 3

Blend 4: 80 wt .-% Example 1/20 wt .-% Example 5 Blend 5: 90 wt .-% Example 1/10 wt .-% Example 6) Blend 6: 75 wt .-% Example 1/25 wt .-% Example 6 Blend 7: 90 wt .-% Example 7/10 wt .-% Example 8 Blend 8: 90 wt .-% Example 9/10 wt .-% Example 10 Blend 9: 75 wt .-% Example 9/25 wt. Example 10 Blend 10: 50 wt.% Example 9/50 wt.% Example 10 Blend 1 1: 25 wt.% Example 9/75 wt.% Example 10

Blend 12: 95% by weight Example 1/5% by weight Example 6

Blend 13: 50% by weight Example 1/50% by weight Example 6 Blend 14: 25% by weight Example 1/75% by weight Example 6

To prepare the coatings, the respective dispersion mixture was applied by knife coating to glass slides which had been cleaned beforehand with acetone and then dried. After the coating has been formed, aftertreatment was carried out as described below in step (e).

The charge structure of the films produced from the dispersion mixtures was achieved in the examples below by subsequent chemical reaction in the context of step (e) of the process according to the invention. For this purpose, those films which contained tert-butyl acrylate in one of the components were tempered at 160 ° C. for three hours. As a result, the tert-butyl group is split off and isobutene is released to form a carboxyl group. Those films containing glycidyl methacrylate in one of the components were wetted with a 10% aqueous triethanolamine solution for 1 hour at room temperature, followed by washing with water and drying at room temperature.

Anti-fouling test (antiscaling)

First, in a 500 ml glass cylinder, a paddle stirrer was modified by attaching 2 glass slides (slides) to it. As a template, a 0.01 molar aqueous solution of CaC was used. The thus prepared glass slides were on the Affixed paddle stirrer, introduced into the 0.01 molar CaC template and carried out the antiscaling experiment in the manner described below. The speed of rotation of the stirrer was set at 100 revolutions per second. In a period of 7 minutes, a 0.01 molar aqueous Na 2 CO 3 solution was added uniformly. Thereafter, stirring was continued for a further 23 minutes at a constant stirring speed. After a total of 30 minutes, the slides were removed from the measuring device and dried. The slide was examined under the microscope for the presence of calcium deposits. Ethanol was then rinsed over the slide with a commercially available PE spray bottle to evaluate the adhesion of calcium carbonate (limescale) to the surface. For this purpose, ethanol was rinsed over the substrate carrier for 30 seconds at intervals of 7 cm.

The assessment of the degree of calcification was based on a scale ++ / + / 07 - / - where ++ indicates the absence of deposits and - strong lime deposits. For comparison, in some of the following examples, in addition to the coatings resulting from the dispersion blends and subsequent chemical reaction of step (e), the corresponding coatings resulting from the individual components and from the dispersion blend without performing step (e) are also listed , The coatings resulting from step (e) are characterized as being "blended".

Example 1 1: Coating resulting from blend 9 in the weight ratio (solids content) A B = 75:25, ratio of the weight-average particle diameter A B = 4.5: 1

Example 12 Coating as a Result of Blend 8 in the Weight Ratio (Solids Content) AB = 90:10, Ratio of the Weight-Average Particle Diameters A / B = 4.5: 1 Mix 8

treated

Right after 0

precipitation

After rinsing 0

with ethanol

Example 13 Coating Resulting from Blend 10 (Comparative Example) in the Weight Ratio (Solids Content) A B = 50:50, Ratio of the Weight-Average Tip Diameter A B = 4.5: 1

Example 14 (comparative example): Coating resulting from blend 1 1 in the weight ratio (solids content) A B = 25:75, ratio of the weight-average tip diameter A / B = 4.5: 1

Example 15: Coating resulting from Blend 5 in the weight ratio (solids content) A / B = 90:10, ratio of the weight-average particle diameter A / B = 7: 1

Example 1 Example 6 Blend 5 Blend 5 treated

Immediately after Fäl- - 0 +

lung

After rinsing - - + ++ with ethanol

Example 16 Coating Resulting from Mixture 6 in the Weight Ratio (Solids Content) A B = 75:25, Ratio of the Weight-Average Particle Diameters A B = 7: 1

Example 17 (comparative example): Coating resulting from blend 12 in the weight ratio (solids content) A B = 95: 5, ratio of the weight-average particle diameter A / B = 7: 1

Example 18 (comparative example): Coating resulting from blend 13 in the weight ratio (solids content) A / B = 50:50, ratio of the weight-average tip diameter A / B = 7: 1

Example 19 (comparative example): Coating resulting from blend 14 in the weight ratio (solids content) A / B = 25:75, ratio of the weight-average tip diameter A / B = 7: 1 Mix 14 Mix 14

treated

Right after Fäl-

lung

After rinsing - -

with ethanol

It can be seen from the examples that the formation of limescale is significantly reduced in the case of charge-structured coatings.

Claims

claims

A process for producing coatings having a periodic structure of surface potential, comprising

(b) mixing the polymer dispersions from step (a) and optionally other components, wherein the weight ratio of component A to component B relative to the solids content in the mixture is from 95 to 5 to 60 to 40,

(c) applying the mixture from step (b) to a surface, preferably a substrate,

(d) solidifying the mixture of step (c) to form a coating, and

(e) further chemically reacting the coating to obtain a periodic structure of surface potential, wherein the ratio of the weight average particle diameter of component A to that of component B is from 3 to 1 to 15 to 1, and the weight average particle diameter of component A is from 75 to 1000 nm and the weight average particle diameter of the component B is from 10 to 200 nm.

The method of claim 1, wherein the further chemical reaction according to step (e) takes place with changing the state of charge of one of the components A o B.

The method of claim 1 or 2, wherein the further chemical reaction according to step (e) takes place under the action of an elevated temperature and cleavage of a molecule.

Process according to claims 1 to 3, wherein the further chemical reaction according to step (e) takes place under the action of a chemical compound.

A process according to any one of the preceding claims wherein the ratio of the weight average particle diameter of component A to that of component B is from 4: 1 to 10: 1.

Method according to one of the preceding claims, wherein the weight-average particle diameter of the component B is from 25 to 150 nm.

7. The method according to any one of the preceding claims, wherein the weight-average particle diameter of the component A is from 100 to 1000 nm.

8. The method according to any one of the preceding claims, wherein the weight ratio of component A to component B based on the solids content of 90 to 10 to 70 to 30.

9. The method according to any one of the preceding claims, wherein the polymer dispersions A and B are obtainable by free-radical emulsion polymerization.

10. Coating obtainable according to one of claims 1 to 9.

1 1. Use of the coating according to claims 1 to 9 for the reduction of deposit formation.

12. Coatings with periodic structure of the surface potential based on polymer latices.

13. Use of coatings with a periodic structure of the surface potential to reduce deposit formation.

14. Use according to claim 13, wherein the coatings are obtained by a process comprising the steps of: (a) providing at least a first polymer dispersion as component A and at least one second polymer dispersion as component B, wherein the components A and B in their distinguish chemical composition,

(B) mixing the polymer dispersions of step (a) and optionally further components, wherein the weight ratio of the component A to

Component B based on the solids content of 95: 5 to 60: 40,

(c) applying the mixture from step (b) to a surface, preferably a substrate,

(d) solidifying the mixture of step (c) to obtain a coating, and

(e) optionally further chemical reaction of the coating to obtain a periodic structure of the surface potential, wherein the ratio of the weight average particle diameter of component A to that of component B is from 3: 1 to 15: 1, by weight the average particle diameter of the component A is from 75 to 1000 nm and the weight average particle diameter of the component B is from 10 to 200 nm.