HK1117854A - Aqueous plastic dispersions, method for producing the same and their use - Google Patents

Description

Aqueous plastic dispersions, method for the production and use thereof

The present invention relates to aqueous plastic dispersions based on vinyl ester copolymers which are substantially stabilized by nonionic components, to a process for their production and to their use.

The plastic dispersions are used as binders in the preparation of pigmented and unpigmented aqueous formulations, for example for use as coatings. Pigmented coating materials include, in particular, glazes, emulsion finishes, emulsion paints, synthetic resin-bound renders, sealing adhesives and fillers, which are widely used in the protective and decorative sector of buildings. The undyed coating includes, for example, a clear finish. Furthermore, plastic dispersions are a major component of water-based food coatings used to protect substrates from moisture loss and deleterious environmental effects.

The coating compositions have to meet a number of practical requirements, for example, sufficient blocking resistance of the dried coating, sufficient stability of the coating to abrasion stresses, in addition to good processability of the aqueous formulation even at low processing temperatures.

In the case of binder-rich coating compositions whose surface is characterized by a high proportion of polymer binder (low pigment volume concentration "PVC"), in addition to blocking resistance and abrasion resistance, the gloss properties of the dried coating are also of primary importance.

These requirements of the coating composition are taken into account in the prior art by different formulation methods.

Some of these methods include the use of organic solvents and/or plasticizers. However, the release of volatile organic components is undesirable due to the harmful effects of the organic components on personnel and the environment, especially in interior decoration applications.

Therefore, there is a great need for aqueous plastic dispersions which make it possible to formulate plasticizer-and solvent-free coating systems with a high binder content (low PVC) or with a low binder content (high PVC) and a low film-forming temperature which meet the requirements with regard to blocking resistance, gloss properties and abrasion properties.

DE a 19811314 discloses multicomponent acrylate dispersions comprising itaconic acid as acidic comonomer, which are preferably prepared using anionic emulsifiers as stabilizers or mixtures of anionic and nonionic emulsifiers as stabilizers. The binders described have advantageous wet abrasion and blocking resistance, but only in coating formulations with plasticizer having a low PVC of 46.9%.

EP a 0347760 recommends the use of specific thiosuccinamide salts as subsequent additives and/or stabilizers during the polymerization of acrylates and styrene/acrylate dispersions. By using the binder thus obtained, a gloss coating agent containing a plasticizer having high blocking resistance can be produced. On the other hand, all other ionic emulsifiers studied had no effect.

EP A0609756 discloses multicomponent acrylate, styrene/acrylate and vinyl/acrylate dispersions, one of the polymer phases having a glass transition temperature of from-55 to-5 ℃ and the other polymer phase having a glass transition temperature of from 0 to 50 ℃. For the preparation of these dispersions, preference is given to using at least one anionic emulsifier and optionally at least one nonionic emulsifier. In the examples, a stabilizer system consisting of nonionic and ionic emulsifiers in a ratio of about 1: 1 is disclosed. They show that the solvent-free semi-gloss, smooth and silky coating examples formulated using the binders of the invention have blocking resistance comparable to solvent-containing systems due to the presence of two polymer phases with specific glass transition temperature ranges.

EP a 1018535 describes solvent-free coating compositions with improved blocking resistance comprising as binder a mixture of acrylate copolymer dispersions and vinyl ester copolymer dispersions. The acrylate component used in the dispersion mixture in a smaller than necessary amount is characterized not only by the necessary copolymerization of the sterically hindered silane, but also by the use of at least one anionic emulsifier during the preparation of the dispersion component to achieve the high blocking resistance desired for coating compositions prepared using these binders. According to the teachings of this disclosure, the use of a nonionic surfactant alone in the preparation of the acrylate component results in insufficient blocking resistance. In contrast, the nature of the emulsifier used in excess to prepare the vinyl ester component has no effect on the blocking resistance of the resulting coating.

Vinyl ester dispersions having a heterogeneous morphology are described in a number of patent applications.

Thus, DE A19853461 discloses protective colloid-stabilized copolymer latex particles having a multiphase morphology, which consist of hard and soft polymer phases, the individual phases preferably having glass transition temperatures of from-40 to +20 ℃ and from +20 to +35 ℃ respectively.

Emulsion polymerization is used for preparing these dispersions, from which dispersion powders are prepared after they have been dried, provision being made for the use of protective colloids. Surface-active substances such as emulsifiers can optionally be used. Also disclosed is the use of copolymer latex particles as binders in emulsion paints and renders.

DE A19739936 discloses plasticizer-free, multiphase vinyl acetate/ethylene dispersions which are stabilized essentially with polyvinyl alcohol as protective colloid and which are prepared by seed polymerization of copolymers A having a glass transition temperature of > 20 ℃ in the presence of a seed binder comprising copolymers B having a glass transition temperature of < 20 ℃.

The dispersions described above in DE A19853461 and DE A19739936 are stabilized substantially by protective colloids. Coating compositions comprising these dispersions as binders are expected to have high coating water absorption due to the associated high content of water-soluble readily swellable polymeric stabilizers, which leads to low abrasion resistance under abrasion load in the swollen state.

EP a 0444827 describes vinyl ester/ethylene/acrylic ester dispersions having a core-shell morphology, the composition of the polymer phases of the core and of the shell being selected such that the copolymer has only one glass transition temperature in the range from-30 to 0 ℃. Also by copolymerization of the specified vinylsilanes, dispersions are obtained which are suitable as advantageous binders for crack-bridging coatings. However, the low glass transition temperature of the core-shell copolymers precludes the use of these soft copolymer dispersions as binders for formulating anti-stiction binder-rich coating compositions.

Finally, WO a 02/74,856 discloses an aqueous plastic dispersion based on vinyl ester copolymers, which is obtainable by multistage polymerization of hard and soft monomer mixtures. The dispersion is predominantly ionically stable. Nonionic emulsifiers and/or structural units derived from monomers having nonionic stabilizing groups may be present, but these are always used in smaller amounts than necessary. The mass ratio of ionic stabilizing groups to nonionic stabilizing groups (emulsifiers and/or groups introduced in the form of polymerized units) cannot be less than 1. In the comparative examples, it is shown that the performance characteristics, in particular the blocking resistance, of coatings comprising binders having a relatively high proportion of non-ionic stabilizing groups are unsatisfactory.

It was therefore an object of the present invention to overcome the disadvantages of the known multiphase vinyl ester dispersions, in particular the abrasion resistance and foam formation of coating compositions formulated using these dispersions, and to provide novel vinyl ester dispersions which make it possible to provide plasticizer-free and solvent-free coating compositions which form crack-free coating films at low temperatures, characterized by improved blocking resistance and excellent abrasion resistance.

It has surprisingly been found that dispersions of heterogeneous vinyl ester copolymers which, in addition to ionic stabilizers, also comprise a comparatively high proportion of nonionic stabilizers and which contain organosilicon compounds incorporated in the form of polymerized units into at least one polymer phase are particularly suitable for formulating solvent-free coatings exhibiting little foam formation and are characterized by a combination of excellent blocking resistance, gloss and abrasion resistance of the coatings produced therefrom.

The invention relates to an aqueous plastic dispersion based on a vinyl ester copolymer having a solids content of at most 80 wt.% and a minimum film-forming temperature of less than 20 ℃, said vinyl ester copolymer being characterized by the following features:

it is a multistage polymer derived from at least one homopolymer or copolymer A and at least one homopolymer or copolymer B,

-said copolymer A is derived from a monomer composition A capable of giving a soft copolymer having a glass transition temperature of 0-20 ℃,

-said homopolymer or copolymer B is derived from a monomer composition B capable of giving a rigid homopolymer or copolymer having a glass transition temperature of between 20 and 50 ℃,

using monomer compositions A and B which give polymers A and B which differ in their glass transition temperature by at least 10K,

the sum of the proportions of polymers A and B in the vinyl ester copolymer is at least 50% by weight, based on the vinyl ester copolymer,

the weight ratio of monomer composition A to monomer composition B is from 95/5 to 5/95,

the monomer composition A comprises from 50 to 100% by weight, based on the total mass of monomers used in the monomer composition A, of at least one vinyl ester of a carboxylic acid (M1) having from 1 to 18 carbon atoms,

the monomer composition B comprises from 50 to 100% by weight, based on the total mass of monomers used in the monomer composition B, of at least one vinyl ester of a carboxylic acid (M1) having from 1 to 18 carbon atoms,

at least one monomer composition A or B comprising from 0.05 to 10% by weight, based on the total mass of monomers used in the monomer composition, of at least one unsaturated copolymerizable organosilicon compound (M4),

the vinyl ester copolymer comprises from 0 to 3% by weight, based on the total mass of monomers used for preparing the vinyl ester copolymer, of structural units derived from at least one ethylenically unsaturated ionic monomer (M3),

the vinyl ester copolymer comprises from 0 to 10% by weight, based on the total mass of monomers used for preparing the vinyl ester copolymer, of structural units derived from at least one ethylenically unsaturated nonionic monomer (M5),

the aqueous plastic dispersion comprises 0-3 wt% of an ionic emulsifier (S1),

the aqueous plastic dispersion comprises at least 0.5% by weight of a nonionic emulsifier (S2), and

the ratio of the total mass of the ionic components (M3) and (S1) to the total mass of the nonionic components (M5) and (S2) used was less than 1.

The monomer compositions A and/or B preferably also comprise up to 25% by weight, based in each case on the total mass of monomers used in the monomer composition, of at least one monoethylenically unsaturated hydrocarbon having 2 to 4 carbon atoms (M2), which is optionally substituted by halogen.

In the present application, the term solids content is understood to mean the total mass of the copolymer based on the total mass of the dispersion.

The solids content of the plastic dispersions of the invention is preferably from 20 to 80% by weight, particularly preferably from 40 to 70% by weight, in particular from 45 to 60% by weight.

The sum of the proportions of polymers A and B in the vinyl ester copolymer is preferably from 75 to 100% by weight, particularly preferably from 80 to 100% by weight, in particular from 85 to 100% by weight, based on the total mass of the copolymer.

The weight ratio of monomer composition A to monomer composition B corresponds to the weight ratio of copolymer A to homopolymer or copolymer B, preferably from 90/10 to 10/90, particularly preferably from 80/20 to 20/80, in particular from 70/30 to 30/70.

The copolymer particle size of the dispersions of the invention can vary within wide limits. However, the average particle diameter is preferably not more than 1000 nm, particularly preferably 600 nm. For optimum coating properties, the average particle size should in particular be less than 350 nm. However, in the case of binder dispersions having a high solids content of more than 60% by weight, based on the total weight of the binder dispersion, it is particularly preferred for viscosity-related reasons if the average particle diameter is greater than 140 nm.

The plastic dispersions of the invention preferably have a pH of from 2 to 9, particularly preferably from 3 to 7.

The minimum film-forming temperature of the inventive heterogeneous vinyl ester dispersions is below 20 ℃. Preferably, the minimum film-forming temperature is less than 10 ℃, particularly preferably less than 5 ℃, in particular less than 0 ℃.

The vinyl ester copolymer particles of the dispersions of the invention are, in the broadest sense, multistage polymers having at least one soft polymer phase (i.e. derived from monomers which will give rise to homopolymers or copolymers having a low Tg) and at least one hard polymer phase (i.e. derived from monomers which will give rise to homopolymers or copolymers having a high Tg), which are prepared by multistage emulsion polymerization, with subsequent stages of polymerization being effected in the presence of a preformed polymerization stage. It is particularly preferred that the multistage polymerization process is a two-stage process by means of which the plastic dispersions of the invention can be prepared.

In the present application, the glass transition temperatures of polymers A and B (T.G.Fox, Bull.Am.Ph.Soc. (Ser.11)1, 123[1956] and Ullmann's Enzyklopadie der technischen Chemie [ Ullmann's Encyclopedia of Industrial Chemistry ], Weinheim (1980), Volume 19, page 1-7-18) are calculated according to the formula of Fox, whereby the following formula is a good approximation of the glass transition temperature Tg of the copolymers in the case of high molar masses,

1/Tg＝X¹/Tg¹+X²/Tg²+......Xⁿ/Tgⁿ

X¹、X²、....Xⁿis mass fraction 1, 2,. n, Tg¹、Tg²、...TgⁿIs the glass transition temperature in degrees kelvin of the polymer consisting in each case of only one of the monomers 1, 2. The latter are disclosed, for example, in Ullmann's Encyclopedia of Industrial Chemistry, VCH Weinheim, Vol.A 21(1992) page 169 or in Brandrup, E.H.Immergut, Polymer Handbook, 3d ed, J.Wiley, New York 1989, for example the glass transition temperature of ethylene homopolymers is 148K (see Brandrup, E.H.Immergut, Polymer Handbook, 3d ed, J.Wiley, New York 1989, page VI/214) and the glass transition temperature of vinyl acetate homopolymers is 315K (see Ullmann's Encyclopedia of Industrial Chemistry, VCH Weinheim, Vol.A 21(1992) page 169). At glass transition temperatureIn the chemical calculation, only the main monomer (M1) and optionally (M2) that contribute mainly to the formation of the phase may be considered, ignoring contributions from other monomers with a mass fraction of less than 2 wt.%, provided that the mass fractions of these monomers do not total more than 4 wt.%.

All monomers known to the person skilled in the art can be used as vinyl esters of carboxylic acids having 1 to 18 carbon atoms (M1).

Vinyl esters of carboxylic acids having 1 to 8 carbon atoms, such as vinyl formate, vinyl acetate, vinyl propionate, vinyl isobutyrate, vinyl pivalate, and vinyl 2-ethylhexanoate; vinyl esters of saturated branched monocarboxylic acids having 9, 10 or 11 carbon atoms in the acid group (® Versatics Rauren); vinyl esters of relatively long-chain, saturated and unsaturated fatty acids, such as vinyl laurate and vinyl stearate; vinyl esters of benzoic acid and vinyl esters of p-tert-butylbenzoic acid and mixtures thereof are preferred.

Vinyl carboxylates having 1 to 4 carbon atoms, mixtures of vinyl acetate and at least one branched alkane carboxylic acid and mixtures of vinyl acetate and vinyl laurate are particularly preferred.

Vinyl acetate is particularly preferred.

Examples of monoethylenically unsaturated hydrocarbons having 2 to 4 carbon atoms (M2) -, also referred to below as monoolefins having 2 to 4 carbon atoms-, which are optionally substituted by halogen are: ethylene, propylene, 1-butene, 2-butene, isobutylene, vinyl chloride and vinylidene chloride, with ethylene and mixtures of ethylene and vinyl chloride being preferred. The proportion of these monomers (M2) in the vinyl ester copolymer is preferably less than 20% by weight, based on the total mass of monomers used for preparing the vinyl ester copolymer.

Preferred monomer mixtures for producing the inventive plastic dispersions from copolymers a and B, including monomers M1 and M2, are: vinyl acetate/vinyl chloride/ethylene, vinyl acetate/vinyl laurate/ethylene/vinyl chloride, vinyl acetate/vinyl versatate/ethylene/vinyl chloride, vinyl acetate/vinyl versatate/ethylene and vinyl acetate/ethylene, with vinyl acetate/ethylene combinations being particularly preferred.

In the present description, ethylenically unsaturated ionic monomers (M3) are understood to mean those ethylenically unsaturated monomers having a water solubility of more than 50 g/l, preferably more than 80 g/l, at 25 ℃ and 1 bar, which are present as ionic compounds in a content of more than 50%, preferably more than 80%, in dilute aqueous solutions at pH 2 and/or pH 11, or which are converted by protonation or deprotonation to ionic compounds in a content of more than 50%, preferably more than 80%, at pH 2 and/or pH 11.

Suitable ethylenically unsaturated ionic monomers (M3) are those compounds which carry carboxyl, sulfo, phosphoric acid or phosphonic acid groups directly adjacent to the double bond unit or connected to the double bond via a spacer. The following may be mentioned as examples: monoesters of α, β -unsaturated C3-C8 monocarboxylic acids, α, β -unsaturated C5-C8 dicarboxylic acids and anhydrides thereof, and α, β -unsaturated C4-C8 dicarboxylic acids.

Unsaturated monocarboxylic acids, preferably such as acrylic acid and methacrylic acid and anhydrides thereof; unsaturated dicarboxylic acids such as maleic acid, fumaric acid, itaconic acid and citraconic acid, and monoesters thereof with C1-C12 alkanols such as monomethyl and mono-n-butyl maleate. Other preferred ethylenically unsaturated ionic monomers (M3) are ethylenically unsaturated sulfonic acids, such as vinylsulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, 2-acryloyloxy and 2-methacryloyloxyethanesulfonic acid, 3-acryloyloxy and 3-methacryloyloxypropanesulfonic acid and vinylbenzenesulfonic acid, and ethylenically unsaturated phosphonic acids, such as vinylphosphonic acid.

In addition to the acids mentioned, it is likewise possible to use their salts, preferably their alkali metal salts or their ammonium salts, in particular their sodium salts, such as the sodium salt of vinylsulfonic acid and the sodium salt of 2-acrylamidopropanesulfonic acid.

The ethylenically unsaturated free acids in aqueous solution at pH 11 are present predominantly in the form of their conjugate bases in anionic form, as are the salts, and may be referred to as anionic monomers.

Furthermore, monomers having cationic functionality, such as those derived from quaternary ammonium groups, are also suitable as ethylenically unsaturated ionic monomers (M3). However, anionic monomers are preferred.

At least one phase A or B derived from the monomer composition, preferably from the soft monomer mixture A, particularly preferably both phases A and B derived from the soft and hard monomer compositions, of the vinyl ester copolymer of the plastic dispersion of the invention, comprises up to 10% by weight, preferably up to 5% by weight, in particular from 0.05 to 2% by weight, particularly preferably from 0.1 to 1.5% by weight, based on the total mass of the respective monomer composition, of at least one unsaturated copolymerizable organosilicon compound (M4), hereinafter also referred to as silane compound, which is incorporated in the form of copolymerized units.

Examples of such organosilicon compounds are monomers of the general formula: RSi (CH3)_0-2(OR¹)_3-1R has the following meaning CH₂＝CR²-(CH₂)_0-1Or CH₂＝CR²-CO₂-(CH₂)_1-3，R¹Is a straight-chain or branched, optionally substituted alkyl radical having 3 to 12 carbon atoms, which may optionally be interrupted by ether groups, R²Is H or CH₃。

General formula is CH₂＝CR²-(CH₂)_0-1-Si(CH₃)_0-1(OR¹)_3-2And CH₂＝CR²-CO₂-(CH₂)₃-Si(CH₃)_0-1(OR¹)_3-2Organosilicon compound of (2), R¹Is a branched or straight chain alkyl group having 1 to 8 carbon atoms, R²Is H or CH3, and is preferred.

Particularly preferred organosilicon compounds are vinylmethyldimethoxysilane, vinylmethyldiethoxysilane, vinylmethyldi-n-propoxysilane, vinylmethyldiisopropyloxysilane, vinylmethyldi-n-butoxysilane, vinylmethyldi-sec-butoxysilane, vinylmethyldi-tert-butoxysilane, vinylmethyldi (2-methoxyisopropoxy) silane and vinylmethyldioctyloxysilane.

General formula is CH₂＝CR²-(CH₂)_0-1-Si(OR¹)₃And CH₂＝CR²-CO₂-(CH₂)₃-Si(OR¹)₃Organosilicon compound of (2), R¹Is a branched or straight chain alkyl group having 1 to 4 carbon atoms, R²Is H or CH3, and is particularly preferred.

Examples of these are gamma- (meth) acryloyloxypropyltri (2-methoxyethoxy) silane, gamma- (meth) acryloyloxypropyltrimethoxysilane, gamma- (meth) acryloyloxypropyltriethoxysilane, gamma- (meth) acryloyloxypropyltri-n-propoxysilane, gamma- (meth) acryloyloxypropyltriisopropoxysilane, gamma- (meth) acryloyloxypropyltributoxysilane, gamma-acryloyloxypropyltri (2-methoxyethoxy) silane, gamma-acryloyloxypropyltrimethoxysilane, gamma-acryloyloxypropyltriethoxysilane, gamma-acryloyloxypropyltri-n-propoxysilane, gamma-acryloyloxypropyltriisopropoxysilane, gamma-acryloyloxypropyltributoxysilane, gamma-acryloyloxyethyltributoxysilane, gamma-acryloyloxypropyltrimethoxysilane, gamma-acryloyloxypropyl, Vinyltris (2-methoxyethoxy) silane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri-n-propoxysilane, vinyltriisopropoxysilane and vinyltributoxysilane. The organosilicon compounds can likewise optionally be used in the form of their (partial) hydrolysates.

Furthermore, the vinyl ester copolymers may comprise up to 10% by weight, preferably up to 5% by weight, of ethylenically unsaturated nonionic monomers (M5), incorporated in the form of copolymerized units, based on the total mass of monomers used in the respective monomer mixture. However, the proportion of these monomers (M5) is preferably less than 2% by weight, particularly preferably less than 1% by weight.

In the present application, ethylenically unsaturated nonionic monomers (M5) are understood to mean those ethylenically unsaturated compounds whose solubility in water at 25 ℃ and 1 bar is greater than 50 g/l, preferably greater than 80 g/l, which are present predominantly in nonionic form in dilute aqueous solutions at pH 2 and 11.

Preferred ethylenically unsaturated nonionic monomers (M5) are not only the amides of the carboxylic acids mentioned in connection with the ethylenically unsaturated ionic monomer (M3), such as (meth) acrylamide and acrylamide, but also water-soluble N-vinyllactams, such as N-vinylpyrrolidone, and those which comprise covalently bonded polyethylene glycol unit compounds as ethylenically unsaturated compounds, such as polyethylene glycol mono-or diallyl ether, or esters of ethylenically unsaturated carboxylic acids with polyalkylene glycols.

In addition, the vinyl ester copolymers may comprise up to 30% by weight, preferably up to 15% by weight, and particularly preferably up to 10% by weight, based on the total mass of monomers present in the respective monomer mixture, of at least one further ethylenically unsaturated monomer (M6), which is incorporated in the form of polymerized units.

Particularly preferred further ethylenically unsaturated monomers (M6) are esters of ethylenically unsaturated C3-C8 monocarboxylic and dicarboxylic acids with C1-C18, preferably C1-C12, particularly preferably C1-C8 alkanols or C5-C8 cycloalkanols. Suitable C1-C18-alkanols are, for example, methanol, ethanol, n-propanol, isopropanol, 1-butanol, 2-butanol, isobutanol, tert-butanol, n-hexanol, 2-ethylhexanol, lauryl alcohol and stearyl alcohol. Suitable cycloalkanols are, for example, cyclopentanol and cyclohexanol. Esters of acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, citraconic acid and fumaric acid are particularly preferred. Esters of acrylic acid and/or (meth) acrylic acid, such as methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, 1-hexyl (meth) acrylate, tert-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, esters of fumaric acid and maleic acid, such as dimethyl fumarate, dimethyl maleate, di-n-butyl maleate, di-n-octyl maleate and di-2-ethylhexyl maleate, are particularly preferred. The esters may also be substituted, if appropriate, by epoxy and/or hydroxyl groups. Furthermore, nitriles of α, β -monoethylenically unsaturated C3-C8-carboxylic acids, such as acrylonitrile and methacrylonitrile, are suitable as ethylenically unsaturated monomers (M6). Conjugated C4-C8-dienes, such as 1, 3-butadiene, isoprene and chloroprene, can also be used as monomers (M6).

The vinyl esters are often partially replaced by said compounds in order to adjust the properties, for example hydrophobicity/hydrophilicity, of the a and/or B homopolymers or copolymers.

In addition, it is well known that those compounds which improve adhesion properties and/or act as crosslinkers can be used as other ethylenically unsaturated monomers (M6).

Adhesion-improving monomers include compounds having acetoacetoxy units covalently bonded to a double bond system and compounds having covalently bonded urea groups. The first-mentioned compounds include, in particular, acetoacetoxy (meth) acrylate ethyl ester and allyl acetoacetate. Compounds comprising urea groups include: such as N-vinyl-and N-allylurea, and derivatives of imidazolin-2-ones, such as N-vinyl-and N-allylimidazolin-2-one, N-vinyloxyethylimidazolin-2-one, N- (2- (meth) acrylamidoethyl) imidazolin-2-one, N- (2- (meth) acryloyloxyethyl) imidazolin-2-one, and N- (2- (meth) acryloyloxyacetamidoethyl) imidazolin-2-one, and other urea-or imidazolin-2-one-based tackifiers well known to those of ordinary skill in the art. Diacetone acrylamide in combination with adipic dihydrazide subsequently added to the dispersion is also suitable for improving adhesion. The adhesion-promoting monomers are optionally used in amounts of from 0.1 to 10% by weight, preferably from 0.5 to 5% by weight, based on the total mass of monomers used in the respective monomer mixture. However, in a preferred embodiment, polymers a and B do not include adhesion promoting monomers introduced as copolymerized units.

Both difunctional and polyfunctional monomers may be used as crosslinking monomers. Examples of these are diallyl phthalate, diallyl maleate, triallyl cyanurate, tetraallyloxyethane, divinylbenzene, butanediol 1, 4-di (meth) acrylate, triethylene glycol di (meth) acrylate, divinyl adipate, allyl (meth) acrylate, vinyl crotonate, methylenebisacrylamide, hexanediol diacrylate, pentaerythritol diacrylate and trimethylolpropane triacrylate. The amount of crosslinking monomers used is optionally from 0.02 to 5% by weight, preferably from 0.02 to 1% by weight, based on the total mass of monomers used in the respective monomer mixture. However, in a preferred embodiment, polymers a and B do not include crosslinking monomers introduced as copolymerized units.

In addition to the vinyl ester copolymer, the aqueous plastic dispersions of the invention comprise from 0 to 3% by weight, preferably from 0.1 to 3% by weight, particularly preferably from 0.5 to 2% by weight, of ionic emulsifiers (S1), based on the total mass of monomers used for preparing the vinyl ester copolymer. The ionic emulsifiers include anionic and cationic emulsifiers, mixtures of anionic and anionic emulsifiers being particularly preferred.

Anionic emulsifiers include: alkyl sulfates (alkyl radical: C6 to C18), alkyl phosphonates (alkyl radical: C6 to C18), sulfuric acid monoesters or phosphoric acid mono-and diesters of ethoxylated alkanols (degree of ethoxylation: 2 to 50, alkyl radical: C6 to C22), ethoxylated alkylphenols (degree of ethoxylation: 3 to 50, alkyl radical: C4 to C9), alkanesulfonic acids (alkyl radical: C12 to C18), alkylarylsulfonic acids (alkyl radical: C9 to C18), sulfosuccinic acid monoesters and sulfosuccinic acid diesters of alkanols (alkyl radical: C6 to C22), ethoxylated alkanols (degree of ethoxylation: 2 to 50, alkyl radical: C6 to C22), non-ethoxylated and ethoxylated alkylphenols (degree of ethoxylation: 3 to 50, alkyl radical: C4 to C9).

In general, the abovementioned emulsifiers are used as technical mixtures, and the data for the alkyl length and the EO chain length relate to the maximum distribution present in each case in the mixture. Examples of such emulsifier classes are ® Texapon K12 (sodium dodecyl sulphate from Cognis), ® Emulsogen EP (C13-C17-alkylsulfonate from Clariant), ® Maranil A25 IS (sodium n-alkyl- (C10-C13) -benzenesulfonate from Cognis), ® Genapol liquid ZRO (C12/C14-alkyl ether sodium sulphate with 3 EO units from Clariant), ® Hostapal BVQ-4 (sodium nonylphenol ether sulphate with 4 EO units from Clariant), ® Aerosol MA 80 (sodium dihexyl sulphosuccinate from Cyctec Industries), ® Aerosol A-268 (disodium isodecyl sulphosuccinate from Cytec Industries), ® Aerosol A-103 (sodium di-sulfosuccinate monoester with nonylphenol ethoxylate from Cytec Industries).

Furthermore, compounds of the general formula (1) are also suitable,

wherein R1 and R2 are hydrogen or C4-C24-alkyl, preferably C6-C16-alkyl, which are not simultaneously hydrogen, and X and Y are alkali metal ions and/or ammonium ions. In the case of these emulsifiers, it is likewise possible to use technical mixtures having proportions of from 50 to 90% by weight of monoalkylated product, for example Dowfax ® 2A1 (R)¹C12-alkyl; DOW Chemical). Such compounds are generally known, for example from U.S. Pat. No. 4,269,749, and are commercially available.

Additionally, Gemini Surfactants well known to those of ordinary skill in the art, for example, in the publications listed therein in the paper "Gemini-Tenside [ Gemini Surfactants ]" (Angew. chem.2000, pages1980-1996) by F.M.Menger and J.S.Keiper, are also particularly suitable as ionic emulsifiers.

The cationic emulsifier includes, for example, alkyl ammonium acetates (alkyl groups: C8 to C12), quaternary compounds including ammonium groups, and pyridinium compounds.

When selecting ionic emulsifiers, it must of course be ensured that incompatibility which can lead to coagulation in the resulting plastic dispersion is excluded. It is therefore preferred to use anionic emulsifiers in combination with anionic monomers (M3) or cationic emulsifiers in combination with cationic monomers (M3), combinations of anionic emulsifiers and anionic monomers being particularly preferred.

In addition to the optionally present ionic emulsifier, the aqueous plastic dispersions of the invention also comprise at least 0.5% by weight of a nonionic emulsifier (S2). These are generally present in amounts of up to 10% by weight, preferably from 0.5 to 5% by weight, based on the total mass of monomers used.

The ratio of the total mass of the ionic components (M3) and (S1) used to the total amount of the nonionic components (M5) and (S2) should be selected so that the ratio is less than 1. It is particularly preferred that the plastic dispersion according to the invention comprises only a nonionic emulsifier (S2) as nonionic component and not structural units derived from ethylenically unsaturated nonionic monomers.

Suitable nonionic emulsifiers (S2) are araliphatic and aliphatic nonionic emulsifiers, for example ethoxylated mono-, di-and trialkylphenol [ phenols (degree of ethoxylation: 3 to 50, alkyl radical: C4 to C9), ethoxylates of long-chain, branched or linear alcohols (degree of ethoxylation: 3 to 50, alkyl radical: C6 to C36) and polyethylene oxide/polypropylene oxide block copolymers.

Preference is given to using ethoxylates of long-chain, branched or unbranched alkanols (alkyl C6-C22, average degree of ethoxylation: 3 to 50), particularly preferably those based on natural, guerbet or oxo alcohols having a linear or branched C12-C18-alkyl radical and a degree of ethoxylation of 10 of 8 to 50.

Other suitable emulsifiers are described in Houben-Weyl, Methoden der organischen Chemie [ Methods of Organic Chemistry ], Volume XIV/l, Makromolekulare Stoffe [ Macromolecular Substances ], Georg-Thierrie-Verlag, Stuttgart, 1961, pages 192-.

In addition, ionic and nonionic emulsifiers comprising one or more unsaturated double bond units as additional functionality and capable of being incorporated into the resulting polymer chain as ethylenically unsaturated ionic monomer (M3) or as ethylenically unsaturated nonionic monomer (M5) may be used during the polymerization process. These compounds, which are known as copolymerizable emulsifiers ("surfactants"), are generally well known to those of ordinary skill in the art. Examples are found in a series of publications (e.g.: A. Guyot et al, "Reactive surfactants in heterologous polymerization" in Acta Polymer.1999, pages 57-66), which are commercially available (e.g. ® Emulsogen R208 from Clariant or Trem LF 40 from Cognis).

In addition, the total mass of the ionic emulsifier (S1) and the ethylenically unsaturated ionic monomer (M3) used to stabilize the plastic dispersion is not more than 3 wt.%, preferably not more than 1 wt.%, based on the total mass of the vinyl ester copolymer.

In addition to the ionic stabilizing component, the plastic dispersions of the present invention also include a nonionic stabilizing component.

The total mass of the nonionic emulsifier (S2) and the ethylenically unsaturated nonionic monomer (M5) used to stabilize the plastic dispersion is not more than 10% by weight, preferably not more than 5% by weight, based on the total mass of the vinyl ester copolymer.

It is particularly preferred that the ratio of the total amount of the ionic components (M3) and (S1) to the total amount of the nonionic components (M5) and (S2) used is 0.0 to 0.9.

In a further preferred embodiment, the plastic dispersion according to the invention comprises protective colloids, preferably polyvinyl alcohols, starch derivatives, cellulose derivatives and vinylpyrrolidone.

Particular preference is given to using polyvinyl alcohol.

The proportion of these components is generally not more than 10% by weight, preferably not more than 5% by weight, based on the total mass of the plastic dispersion.

The invention likewise relates to a process for producing the aqueous plastic dispersions based on vinyl ester copolymers according to the invention.

The invention therefore likewise relates to a process for producing plastic dispersions by free-radical aqueous emulsion polymerization of monomers or mixtures of monomers B, first of all, preparing a homopolymer or copolymer B, then preparing the homopolymer or copolymer A by free-radical emulsion polymerization of the monomer or monomer mixture A in an aqueous dispersion of the homopolymer or copolymer B, free-radical emulsion polymerization in the presence of a nonionic emulsifier (S2), optionally in the presence of ethylenically unsaturated ionic monomers (M3) and/or ionic emulsifiers (S1), so that the total mass of the nonionic emulsifiers (S2) in the end product is at least 0.5% by weight, the ratio of the total mass of the ionic components (M3) and (S1) used in the end product to the total mass of the nonionic components (M5) and (S2) is less than 1, with the proviso that the preparation of the homopolymer or copolymer B can also be effected after the preparation of the homopolymer or copolymer A.

The preparation is effected by a so-called step-by-step polymerization. This is generally understood to mean a process in which the monomers of the first stage are polymerized in a first stage by free-radical, aqueous emulsion polymerization, preferably in the presence of a seed emulsion which is preferably prepared in situ, and the monomers of the second stage are then polymerized in the aqueous dispersion of the polymer obtained in the first stage. If appropriate, further polymerization stages may follow. Here, the type of monomers and/or the relative amounts of the monomers to each other between the first and second stage comonomers should be distinguished. Preferably, the type of monomer to be polymerized is the same for both stages. Thus, only the relative amounts of the monomers differ from one another.

In general, when selecting the monomer compositions of the individual stages, a process is taken in which, in a first stage, a monomer composition B is selected which leads to the formation of a homopolymer or copolymer B and, in a further stage, preferably a second stage, the polymerization leads to the formation of a corresponding monomer or monomer mixture A of a homopolymer or copolymer A.

However, it is likewise possible to proceed in the reverse manner, producing the homopolymer or copolymer B in the presence of the previously prepared homopolymer or copolymer A, and optionally further stages.

Vinyl ester copolymers prepared by stepwise polymerization include, regardless of the morphology which is discernible, all copolymers in which the polymer components A and B have been produced by emulsion polymerization in successive stages.

The monomer composition A for producing the homo-or copolymers A comprises, based on the total amount of monomers used in the monomer composition A, more than 50% by weight, preferably more than 70% by weight, particularly preferably more than 80% by weight, in particular from 80 to 95% by weight, of monomers (M1), less than 25% by weight, preferably from 5 to 20% by weight, particularly preferably from 10 to 15% by weight, of monoolefins having from 2 to 4 carbon atoms (M2), from 0 to 10% by weight, preferably from 0.05 to 5% by weight, of at least one unsaturated copolymerizable organosilicon compound (M4) and preferably up to 1% by weight of ionic monomers (M3), the composition of the monomer mixture being selected such that the glass transition temperature of the copolymers polymerized alone using this monomer mixture is from 0 to 20 ℃, preferably from 0 to 15 ℃, particularly preferably from 0 to 10 ℃.

The monomer composition for producing the homo-or copolymer B comprises more than 50 wt.%, preferably more than 70 wt.%, particularly preferably more than 80% by weight, in particular from 90 to 98% by weight, of the monomer (M1), less than 25% by weight, preferably less than 20% by weight, particularly preferably from 0.1 to 10% by weight, and in particular from 0.1 to 5% by weight, of a monoolefin having from 2 to 4 carbon atoms (M2), and 0 to 10% by weight, preferably 0.05 to 5% by weight, of at least one unsaturated copolymerizable organosilicon compound (M4) and preferably up to 1% by weight of ionic monomers (M3), the composition of the monomer (mixture) B being selected such that the glass transition temperature of the homopolymers or copolymers polymerized separately using this monomer mixture is from 20 to 50 ℃, preferably from 25 to 45 ℃, particularly preferably from 30 to 43 ℃.

In addition, when selecting the monomer composition of the two polymers A and B of the multiphase vinyl ester copolymer, it should be ensured that the difference in glass transition temperature phases is greater than 10K, preferably greater than 15K, particularly preferably greater than 20K.

It is particularly preferred when the monomer composition is selected, that less than 20% by weight, preferably from 0.1 to 20% by weight, particularly preferably from 0.1 to 15% by weight, of the ethylenically unsaturated monoolefin (M2) having from 2 to 4 carbon atoms, based on the total amount of monomers used to prepare the copolymer, is used.

In certain embodiments, due to the different proportion of monoolefin (M2) present as a gaseous aggregate under the reaction conditions, it may be desirable to carry out separate polymerization stages at different polymerization pressures. In these cases, the pressure established by metering the gaseous monomer component (M2), during the polymerization of the monomer composition to give the copolymer B, is preferably from 0 to 10 bar, particularly preferably from 2 to 10 bar, and, during the polymerization of the monomer composition to give the copolymer A, is preferably from 10 to 120 bar, particularly preferably from 20 to 60 bar.

It was surprisingly found that, as is usually carried out for the formation of the individual polymer phases, it is not necessary for the individual stages of polymerization to reach a monomer content of < 0.3% for the preparation of the vinyl ester copolymer, copolymer a being prepared in the presence of copolymer B.

In a particularly preferred embodiment, it is sufficient for copolymer a (pressure build-up) to be formed after the production of copolymer B if the concentration of monomer component M2 present in gaseous form under the reaction conditions increases within suitable time intervals progressively with successive metering of the liquid monomer component. The process is characterized by a substantial reduction in reactor residence time compared to commonly used processes.

The polymerization is generally carried out at temperatures in the range from 20 to 120 ℃, preferably from 40 to 95 ℃ and particularly preferably from 50 to 90 ℃.

The aqueous plastic dispersions based on vinyl ester copolymers according to the invention are preferably produced by free-radical, aqueous emulsion polymerization of the monomers mentioned in the presence of at least one free-radical polymerization initiator and at least one surface-active substance.

Suitable free-radical polymerization initiators are all known initiators which are capable of initiating a free-radical aqueous emulsion polymerization. They may be peroxides, such as alkali metal peroxodisulfates and azo compounds. Other polymerization initiators which may be used are the so-called redox initiators which consist of at least one organic and/or inorganic reducing agent and at least one peroxide and/or hydroperoxide, for example tert-butyl hydroperoxide with sulfur-containing compounds, such as the sodium salt of hydroxymethanesulfinic acid, sodium sulfite, sodium bisulfite, sodium thiosulfate and acetone bisulfite adducts, or hydrogen peroxide with ascorbic acid. It is also possible to use combination systems comprising small amounts of metal compounds which are soluble in the polymerization medium and whose metal components can be present in a plurality of valency states, such as ascorbic acid/iron sulfate/hydrogen peroxide, it also being customary to use the sodium salt of hydroxymethanesulfinic acid, acetone bisulfite adduct, sodium sulfite, sodium bisulfite or sodium bisulfite in place of ascorbic acid and of organic peroxides, such as tert-butyl hydroperoxide, or to use alkali metal peroxodisulfates and/or ammonium peroxodisulfate in place of hydrogen peroxide. Instead of the acetone bisulfite adduct, it is likewise possible to use other bisulfite adducts which are known to the person skilled in the art, such as the adducts described in EP-A-0778290 and in the documents cited therein. Other preferred initiators are peroxodisulfates, such as sodium peroxodisulfate. The amount of free-radical initiator system used is preferably from 0.05 to 2.0% by weight, based on the total amount of monomers to be polymerized.

Protective colloids and, in contrast to protective colloids, the abovementioned ionic and nonionic emulsifiers S1 and S2, whose relative molar amounts are below 2000g/mol, are generally used as surface-active substances in emulsion polymerization.

The surface-active substances are generally used in amounts of up to 10% by weight, preferably from 0.5 to 7% by weight, particularly preferably from 1 to 6% by weight, based on the monomers to be polymerized.

In a preferred embodiment of the process according to the invention, the emulsion polymerization is carried out in the presence of protective colloids, preferably, for example, polyvinyl alcohols, starch derivatives, cellulose derivatives, vinylpyrrolidone, polyvinyl alcohols and cellulose derivatives such as hydroxyethylcellulose.

Further details of suitable protective colloids are given in Houben-Weyl, Methoden der organischen Chemie [ Methods of Organic Chemistry ], Volume XIV/l, Makromolekulare Stoffe [ Macromolecular Substances ], Georg Thieme Verlag, Stuttgart 1961, pages 411 to 420.

The molecular weight of the vinyl ester copolymer can be adjusted by adding small amounts of one or more molecular weight-regulating substances. These so-called "regulators" are generally used in amounts of up to 2% by weight, based on the monomers to be polymerized. "regulators" which may be used are those substances which are well known to the person skilled in the art.

For example, organosulfur compounds, silanes, allylalcohols, and aldehydes are preferred.

The emulsion polymerization is generally carried out by a batch process, preferably by a semi-continuous process. In the semi-continuous process, the major amount, i.e., at least 70%, preferably at least 90%, of the monomer to be polymerized is continuously added (including the step gradient process) to the polymerization batch. This process is likewise referred to as the monomer feed process, monomer feed being understood to mean the metered addition of gaseous monomers, liquid monomer mixtures, monomer solutions or, in particular, aqueous monomer emulsions. The metering of the individual monomers can be effected by separate addition.

In addition to the seedless preparation method, the emulsion polymerization can also be effected by a seeded emulsion method, or in the presence of a seeded grid made in situ, to form a defined polymer particle size. Such methods are known and described in detail in numerous patent applications (for example EP-A-0040419 and EP-A-0567812) and publications ("encyclopediｃA of Polymer science and Technology", Vol.5, John Wiley & Sons Inc. New York1966, page 847).

After the actual polymerization reaction, it is desirable and/or necessary to substantially release the aqueous plastic dispersion of the present invention from odorous substances such as residual monomers and other volatile organic components. This can be achieved in a manner known per se, for example by physical distillation removal, in particular via steam distillation, or by stripping with inert gas. Furthermore, the reduction of residual monomers can also be achieved chemically by free-radical postpolymerization, in particular under the action of redox initiator systems, as described, for example, in DE-A-4435423. Postpolymerization with redox initiator systems comprising at least one organic peroxide and one organic and/or inorganic sulfite is preferred. A combination of physical and chemical processes is particularly preferred, with a further reduction of the residual monomer content to preferably < 1000ppm, particularly preferably < 500ppm, in particular < 100ppm, being achieved by physical processes after the reduction of the residual monomer content by chemical post-polymerization.

The aqueous plastic dispersions of the invention based on vinyl ester copolymers are used, for example, as binders in pigmented aqueous preparations for coating substrates. These include, for example, renders incorporating synthetic resins, tile adhesives, coatings, such as emulsion paints, emulsion finishes, and glazes, sealing compounds and sealing compositions, preferably slip agents for porous structures and paper coating.

However, the aqueous plastic dispersions can also be used as aqueous preparations for coating substrates directly or after addition of rheology-modifying additives and/or other components. Such aqueous phase preparations are, for example, primers, clear coatings, or food coatings, which protect food products such as cheese or meat-containing products from harmful environmental influences and/or from moisture loss.

The present invention therefore further relates to aqueous-phase formulations comprising the aqueous plastic dispersions based on vinyl ester copolymers according to the invention. The aqueous phase preparation containing the pigment is a preferred embodiment of the aqueous phase preparation.

These are preferably pigment-containing preparations, particularly preferably emulsion paints, which generally comprise from 30 to 75% by weight, preferably from 40 to 65% by weight, of nonvolatile constituents. These are understood to mean all formulation constituents other than water, but at least the total amount of solid binders, fillers, pigments, plasticizers and polymer auxiliaries.

The non-volatile components are preferably:

a) the solid binder, i.e.the vinyl ester copolymer, represents 3 to 90 wt.%, particularly preferably 10 to 60 wt.%,

b)5 to 85 wt.%, particularly preferably 10 to 60 wt.%, of at least one inorganic pigment,

c)0 to 85 wt.%, particularly preferably 20 to 70 wt.%, of an inorganic filler, and

d) from 0.1 to 40% by weight, particularly preferably from 0.5 to 15% by weight, of customary auxiliaries.

Aqueous phase formulations which are free of solvents and plasticizers are particularly preferred.

The Pigment Volume Concentration (PVC) of the pigment-containing aqueous preparations of the invention is generally above 5%, preferably from 10 to 90%. In particularly preferred embodiments, the PVCs are in the range of from 10 to 45%, or from 60 to 90%, especially from 70 to 90%.

Pigments which can be used are all pigments known to the person skilled in the art for the intended use. Preferred pigments for aqueous preparations according to the invention, preferably for emulsion paints, are, for example, titanium dioxide (preferably in the rutile form), barium sulfate, zinc oxide, zinc sulfide, basic lead carbonate, antimony trioxide and lithopone (zinc sulfide and barium sulfate). However, the aqueous phase formulation may also comprise coloured pigments, such as iron oxides, carbon black, graphite, luminescent pigments, zinc yellow powder, zinc green, ultramarine, manganese black, antimony sulphide, manganese violet, paris blue or Schweinfurt green. In addition to inorganic pigments, the formulations of the present invention may also include organic colored pigments such as sepia dyes, gamboges, casserole brown earth, toluidine red, para-red, hansa yellow, indigo, azo dyes, anthraquinone-type pigments, indigoid dyes, dioxazine, quinacridone, phthalocyanine, isoindolinone and metal complex pigments.

Fillers which can be used are all fillers known to the person skilled in the art for the intended use. Preferred fillers are aluminosilicates such as feldspar, silicates such as kaolin, talc, mica, magnesite, alkaline earth metal carbonates such as calcium carbonate, for example in the form of calcite or chalk, magnesium carbonate, dolomite, alkaline earth metal sulfates such as calcium sulfate, and silica. The filler may be used as a separate component or as a mixture of fillers. Filler mixtures such as calcium carbonate/kaolin and calcium carbonate/talc are preferred in practice. Renders incorporating synthetic resins may also include relatively coarse aggregates such as sand or sandstone particles.

In general, finely divided fillers are preferred in emulsion paints.

In order to increase hiding power and save white pigments, finely divided fillers such as precipitated calcium carbonate or mixtures of different calcium carbonates having different particle sizes are generally preferred for use in emulsion paints. Mixtures of colored pigments and fillers are preferably used to adjust the color hiding power and color depth.

Typical auxiliaries include wetting or dispersing agents, such as sodium, potassium or ammonium polyphosphates, alkali metal and ammonium salts of polyacrylic and polymaleic acids, polyphosphonates, such as sodium 1-hydroxyethane-1, 1-diphosphonate, and naphthalene sulfonates, especially the sodium salts thereof. In addition, suitable aminoalcohols, such as 2-amino-2-methylpropanol, may be used as dispersing agents. The dispersing or wetting agents are preferably used in amounts of from 0.1 to 2% by weight, based on the total weight of the emulsion paint.

Further, the auxiliaries may also comprise thickeners, for example cellulose derivatives such as methylcellulose, hydroxyethylcellulose and carboxymethylcellulose, further casein, gum arabic, tragacanth, starch, sodium alginate, polyvinyl alcohol, polyvinylpyrrolidone, sodium polyacrylate and water-soluble copolymers based on acrylic acid and (meth) acrylic acid, such as acrylic acid/acrylamide and meth) acrylic acid/acrylate copolymers, and so-called associative thickeners, such as styrene/maleic anhydride polymers, or preferably hydrophobically modified polyether polyurethanes (HEUR), hydrophobically modified acrylic acid copolymers (HASE) polyether polyols, which are well known to the person skilled in the art.

Inorganic thickeners such as bentonite or hectorite may also be used.

The thickeners are preferably used in amounts of from 0.1 to 3% by weight, particularly preferably from 0.1 to 1% by weight, based on the total weight of the aqueous preparation.

The aqueous phase formulation of the present invention may also include a crosslinking additive. Such additives may be: aromatic ketones, such as alkyl phenyl ketones, optionally having one or more substituents on the phenyl ring, or benzophenones and substituted benzophenones, are used as photoinitiators. Photoinitiators suitable for this purpose are disclosed, for example, in DE-A-3827975 and EP-A-0417568. If the vinyl ester copolymer P comprises carbonyl-containing monomers introduced in the form of copolymerized units, suitable compounds having a crosslinking effect may also be water-soluble compounds having at least two amino groups, for example dihydrazides of aliphatic dicarboxylic acids, as disclosed, for example, in DE-A-3901073.

In addition, paraffin and polyethylene based waxes, delusterants, defoamers, preservatives and water repellents, biocides, fibers and other additives well known to those of ordinary skill in the art may also be used as adjuvants for the aqueous phase formulations of the present invention.

The dispersions of the invention can be used not only for the production of formulations which are free of solvents and plasticizers, but of course likewise for the production of coating systems which comprise solvents and/or plasticizers as film-forming assistants. Film-forming auxiliaries are generally known to the person skilled in the art in amounts of from 0.1 to 20% by weight, based on the vinyl ester copolymer present in the formulation, so that the minimum film-forming temperature of the aqueous formulation is less than 15 ℃ and preferably from 0 to 10 ℃. The use of these film-forming auxiliaries is of course not necessary in view of the advantageous properties of the plastic dispersions of the invention. In a preferred embodiment, the aqueous phase formulation of the present invention therefore does not comprise a film-forming aid.

The aqueous phase formulations of the present invention are stable fluid systems that can be used to coat a wide variety of substrates. The invention therefore likewise relates to a method for coating a substrate and to the coating itself. Suitable substrates are, for example, wood, concrete, metal, glass, ceramic, plastic, renders, wallpaper, paper and coated, primed or weathered substrates. Depending on the formulation form, the formulation is applied to the substrate to be coated in a certain manner. Application is effected by rolling, brushing, knife coating or spraying, depending on the viscosity and pigment content of the formulation and the substrate.

The present invention is described in more detail below with reference to examples, but is not limited thereto in any way.

Production and characterization of the Plastic Dispersion of the invention

The dispersions produced in the examples and comparative examples were produced in a pressure reactor with jacket cooling with a permissible pressure range of up to 160 bar of 70L. Parts and percentages used in the following examples are based on weight, unless otherwise indicated.

Comparative example 1

Vinyl acetate/ethylene copolymer dispersions not according to the invention were produced, with subsequent removal of residual monomers.

An aqueous solution consisting of the following components was introduced into a pressure apparatus with stirrer, jacket heating and metering pump:

18813g of water, 84.2g of sodium acetate, 5033g of a 20 wt% strength aqueous nonylphenol ethoxylate solution containing 30mol of ethylene oxide, 67.1g of sodium lauryl sulfate, 2013g of a 10% strength by weight aqueous polyvinyl alcohol solution (4% strength by weight aqueous solution having a viscosity of 23 mPas), 566g of a 30 wt% strength aqueous sodium vinylsulfonate solution and 33g of 1% strength by weight FeII (SO)₄)×7H₂An aqueous solution of O. The pH of the solution was 7.2. Atmospheric oxygen was removed from the apparatus and ethylene was forcibly introduced into the apparatus. A mixture of 13.1g of Vinyltrimethoxysilane (VTM), 2932g of vinyl acetate and 2.63g of Brugolit E01 dissolved in 194g of water is metered in at an ethylene pressure of 20 bar. Heated to an internal temperature of 60 ℃ and 3.75g of a 70% strength aqueous solution of tert-butyl hydroperoxide in 194g of water are metered in at 50 ℃. The reaction heat was removed by cooling. Once 60 ℃ has been reached, a mixture of 121.1g of Vinyltrimethoxysilane (VTM) and 27.135g of vinyl acetate is metered in over 240 minutes, 26.6g of Bruggolit E01 dissolved in 1964g of water is metered in over 240 minutes, and a solution of 38g of an aqueous solution of 70% strength tert-butyl hydroperoxide in 1964g of water is added during 240 minutes, the ethylene pressure being maintained at 35 bar until 3355g of ethylene are present in the reactor. After the end of the metering, 33.6g of sulfurous acid are metered in792g of sodium in water, the internal temperature was increased to 80 ℃ and maintained at this temperature for 1 hour. Then, most of the unconverted ethylene was discharged in gaseous form with stirring, and 2L of water were added. Thereafter, 2L of water were distilled off under vacuum applied over a period of 2 hours, with the result that the vinyl acetate content of the residual dispersion was reduced to 0.05% by weight, based on the dispersion.

Examples C2 and 3 to 7

Production processes which are customarily used for the production of vinyl acetate/ethylene copolymer dispersions, with subsequent removal of residual monomers.

An aqueous solution consisting of the following components was introduced into a pressure apparatus with stirrer, jacket heating and metering pump.

18813g of water, 84.2g of sodium acetate, 5033g of a 20 wt% strength aqueous nonylphenol ethoxylate solution containing 30mol of ethylene oxide, 67.1g of sodium lauryl sulfate, 2013g of a 10% strength by weight aqueous polyvinyl alcohol solution (the viscosity of the 4% strength by weight aqueous solution is 23 mPas), 566g of a 30 wt% strength aqueous solution of sodium vinylsulfonate and 33g of a 1% strength by weight aqueous solution of FeII (SO 4). times.7H 2O. The pH of the solution was 7.2. Atmospheric oxygen was removed from the plant and 335g of ethylene were forced into the plant and the ethylene feed was shut off. At room temperature, 30% of the monomer mixture B dissolved in 194g of water and 2.63g of Brugolit E01 are metered in. Heated to an internal temperature of 60 ℃ and 3.75g of a 70% strength aqueous solution of tert-butyl hydroperoxide in 194g of water are metered in at 50 ℃. The reaction heat was removed by cooling. Once 60 ℃ has been reached, 70% of the monomer mixture B is metered in over 90 minutes, 26.6g of Brugolit E01 dissolved in 1964g of water is metered in over 360 minutes, and 38g of an 70% strength aqueous solution of tert-butyl hydroperoxide in 1964g of water is metered in over 360 minutes. After the end of the metering of the monomer mixture B, the monomer mixture A was metered in over a period of 270 minutes, the pressure in the vessel was increased to 40 bar by opening the ethylene feed, and the ethylene feed was kept open at this pressure until a further 3020g of ethylene had been metered in. After the end of the metering of the monomer mixture A, 792g of an aqueous solution of 33.6g of sodium persulfate were metered in, the internal temperature was increased to 80 ℃ and maintained at this temperature for 1 hour. Thereafter, most of the unconverted ethylene was discharged in gaseous form with stirring, and 2L of water were added. Thereafter, 2L of water were distilled off under vacuum applied over a period of 2 hours, with the result that the residual vinyl acetate content of the dispersion was reduced to 0.05% by weight, based on the dispersion.

Examples 3-7 and comparative example C2 were prepared according to this general production method. The detailed compositions of the dispersions of examples C2 and 3-7 are shown in table 1 below.

TABLE 1

	Monomer mixture B	Monomer mixture A
			Comparative example 2	9815g of vinyl acetate	20385 g of vinyl acetate
Example 3	9772g of vinyl acetate and 43.6g of vinyltrimethoxysilane	20295 g of vinyl acetate and 90.6g of vinyltrimethoxysilane
			Example 4	9681g of vinyl acetate and 134.2g of vinyltrimethoxysilane	20385 g of vinyl acetate
Example 5	9815g of vinyl acetate	20251 g of vinyl acetate and 134.2g of vinyltrimethoxysilane
			Example 6	9717g of vinyl acetate and 98.1g of vinyltrimethoxysilane	20181 g of vinyl acetate and 203.9g of vinyltrimethoxysilane
Example 7	9793g of vinyl acetate and 21.8g of vinyltrimethoxysilane	20340 g of vinyl acetate and 45.3g of vinyltrimethoxysilane

Examples of the use

The invention is characterized in more detail below by formulating emulsion paints or emulsion finishes having the compositions shown below in tables 2, 4 and 6.

Table 2: emulsion paint with 77% PVC

Composition (I)	Parts by weight
		Water (W)	301.5
Dispersion (sodium polyphosphate, 10% strength solution)	5.0
		Cellulose ether (type MH, high viscosity)	4.0
Dispersants, sodium salts of polyacrylic acids	3.5
		Mineral oil-based antifoaming agents	2.0
10% strength sodium hydroxide solution	2.0
		Pigment, titanium dioxide	80.0
Filler, calcium carbonate, particle size 2 μm	235.0
		Filler, calcium carbonate, particle size 5 μm	205.0
Fillers, aluminium silicates	35.0
		Copolymer dispersions1)	125.0
Preservative	2.0

¹⁾Using the copolymers of examples 2 to 7 (see Table 1)

Powdered methylhydroxyethyl cellulose was sprayed onto water and dissolved with stirring, after which a sodium salt solution of polyacrylic acid and polyphosphoric acid and a 10% strength by weight sodium hydroxide solution were added with stirring. Preservatives and antifoams were added to the viscous solution obtained. First, aluminum silicate was dispersed by a dissolver with stirring at a stirring speed of 2000rpm, and then titanium dioxide and calcium carbonate types were added, and the stirring speed was increased to 5000 rpm. Disperse at 5000rpm for an additional 20 minutes and the temperature of the pigment/filler paste is increased to 60 ℃. It was left to cool to 30 ℃. The pH was 9.3.

To investigate the parameters of the described copolymer dispersions, 875g of pigment/filler paste in each case were stirred together with 125g of the copolymer dispersion to be tested in each case (3 minutes, Lenard stirrer, 1500 rpm). An emulsion paint with a solids content of about 63% and a Pigment Volume Concentration (PVC) of about 77% was obtained.

The Wet Scrub Resistance (WSR) of these coatings was tested by the nonwoven insertion method (ISO 11998). For this purpose, the coating abrasion (amount) due to the loss of the coating film amount after 28 days (28d) of storage was determined. The paint abrasion in μm was then calculated from the paint density, the scrub surface area and the amount of film loss.

The main characteristic of different emulsion paints is the scrub resistance (WSR). The test results are shown in table 3.

Table 3:

	WSR[μm]
		comparative example 2 (without silane)	75
Example 3	50
		Example 4	53
Example 5	40
		Example 6	36
Example 7	54

Table 4: emulsion paint with PVC of 54.7%

Composition (I)	Parts by weight
		Water (W)	285.6
Cellulose ether (type MH, high viscosity)	2.7
		Dispersants, sodium salts of polyacrylic acids	5.4
Mineral oil-based antifoaming agents	5.4
		10% strength sodium hydroxide solution	2.7
Pigment, titanium dioxide	271.5
		Fillers, calcium carbonate, particle size 1 μm	203.7
Copolymer dispersions1)	200.0
		PU thickener 20% strength solution	20.4
Preservative	2.7

¹⁾Using the copolymers of examples 2 to 7 (see Table 1)

Powdered methylhydroxyethyl cellulose was sprayed onto water and dissolved with stirring, after which a sodium salt solution of polyacrylic acid and a 10% strength by weight sodium hydroxide solution were added with stirring. Preservatives and antifoams were added to the viscous solution obtained. Titanium dioxide and calcium carbonate were added by a dissolver with stirring at a stirring speed of 5000 rpm. Disperse at 5000rpm for an additional 20 minutes and the temperature of the pigment/filler paste is increased to 60 ℃. It was left to cool to 30 ℃. The pH was 9.3.

To investigate the parameters of the described copolymer dispersions, 800g of pigment/filler paste in each case were stirred together with 200g of the copolymer dispersion to be tested in each case (3 minutes, Lenard stirrer, 1500 rpm). An emulsion paint with a Pigment Volume Concentration (PVC) of about 55% was obtained.

The Wet Scrub Resistance (WSR) of these coatings was tested by the nonwoven insertion method (ISO 11998). For this purpose, the coating abrasion (amount) due to the loss of the coating film amount after 28 days (28d) of storage was determined. The paint abrasion in μm was then calculated from the paint density, the scrub surface area and the amount of film loss.

The main characteristic of different emulsion paints is the scrub resistance (WSR). The test results are shown in table 5.

Table 5:

	WSR[μm]
		comparative example 2 (without silane)	33
Example 3	28
		Example 4	30
Example 5	25
		Example 6	22
Example 7	30

Table 6: emulsion paint with 38% PVC

Composition (I)	Parts by weight
		Water (W)	214.2
Cellulose ether (type MH, high viscosity)	2.0
		Dispersants, sodium salts of polyacrylic acids	4.0
Mineral oil-based antifoaming agents	4.0
		10% strength sodium hydroxide solution	2.0
Pigment, titanium dioxide	203.6
		Fillers, calcium carbonate, particle size 1 μm	152.7
Copolymer dispersions1)	400.0
		PU thickener 20% strength solution	15.3
Preservative	2.0

¹⁾Using the copolymers of examples 2 to 7 (see Table 1)

Powdered methylhydroxyethyl cellulose was sprayed onto water and dissolved with stirring, after which a sodium salt solution of polyacrylic acid and a 10% strength by weight sodium hydroxide solution were added with stirring. Preservatives and antifoams were added to the viscous solution obtained. Titanium dioxide and calcium carbonate were added by a dissolver with stirring at a stirring speed of 5000 rpm. Disperse at 5000rpm for an additional 20 minutes and the temperature of the pigment/filler paste is increased to 60 ℃. It was left to cool to 30 ℃. The pH was 9.3.

To investigate the parameters of the described copolymer dispersions, 600g of pigment/filler paste in each case were stirred together with 400g of the copolymer dispersion to be tested in each case (3 minutes, Lenard stirrer, 1500 rpm). An emulsion paint with a Pigment Volume Concentration (PVC) of about 37.7% was obtained.

The Wet Scrub Resistance (WSR) of these coatings was tested by the nonwoven insertion method (ISO 11998). For this purpose, the coating abrasion (amount) due to the loss of the coating film amount after 28 days (28d) of storage was determined. The paint abrasion in μm was then calculated from the paint density, the scrub surface area and the amount of film loss.

To test the blocking resistance of the 38% PVC coating formulation, a microscope slide was coated with the corresponding emulsion finish using a knife coater with a 200 μm tip. After drying for 24 hours under standard climatic conditions (23 ℃, relative humidity 50%), two coated microscope slides were placed one on top of the other with their coated sides under a load of 1 kg at room temperature for 1 hour. The weight required to separate the coated slides from each other is then determined again.

The main features of different emulsion paints are the scrub resistance (WSR) and the blocking resistance. The test results are shown in table 7.

Table 7:

	WSR[μm]	blocking resistance g/6.25cm2
			Comparative example 1	7	2000
Comparative example 2 (without silane)	8	830
			Example 3	6	600
Example 4	7	660
			Example 5	5	550
Example 6	4	500
			Example 7	7	690

The measured values of the wet scrub resistance of the emulsion paints produced using the dispersions of the invention (example 5) clearly show that: considerable improvement in WSR can be achieved compared to emulsion paints produced using dispersions having a uniform silane distribution in the copolymer (example 3). In addition, these emulsion paints are characterized in that: the blocking resistance is considerably improved compared with emulsion paints produced according to comparative example 1 using dispersions not according to the invention, and with a PVC of 38%.

Claims (33)

1. An aqueous plastic dispersion based on a vinyl ester copolymer having a solids content of up to 80% by weight and a minimum film-forming temperature of less than 20 ℃, the vinyl ester copolymer being characterized by the following features:

it is a multistage polymer derived from at least one homopolymer or copolymer A and at least one homopolymer or copolymer B,

the copolymer A is derived from a monomer composition A which gives a soft copolymer having a glass transition temperature of from 0 to 20 ℃,

the homopolymer or copolymer B is derived from a monomer composition B capable of giving a rigid homopolymer or copolymer having a glass transition temperature of from 20 to 50 ℃,

using monomer compositions A and B which give polymers A and B which differ in their glass transition temperature by at least 10K,

the sum of the proportions of polymers A and B in the vinyl ester copolymer is at least 50% by weight, based on the vinyl ester copolymer,

the weight ratio of monomer composition A to monomer composition B is from 95/5 to 5/95,

the monomer composition A comprises from 50 to 100% by weight, based on the total mass of monomers used in the monomer composition A, of at least one vinyl ester of a carboxylic acid (M1) having from 1 to 18 carbon atoms,

the monomer composition B comprises from 50 to 100% by weight, based on the total mass of monomers used in the monomer composition B, of at least one vinyl ester of a carboxylic acid (M1) having from 1 to 18 carbon atoms,

at least one monomer composition A or B comprising from 0.05 to 10% by weight, based on the total mass of monomers used in the monomer composition, of at least one unsaturated copolymerizable organosilicon compound (M4),

the vinyl ester copolymer comprises from 0 to 3% by weight of structural units derived from at least one ethylenically unsaturated ionic monomer (M3), based on the total mass of monomers used to prepare the vinyl ester copolymer,

-the vinyl ester copolymer comprises from 0 to 10% by weight of structural units derived from at least one ethylenically unsaturated nonionic monomer (M5), based on the total mass of monomers used for preparing the vinyl ester copolymer,

the aqueous plastic dispersion comprises 0-3 wt% of an ionic emulsifier (S1),

the aqueous plastic dispersion comprises at least 0.5 wt% of a non-ionic emulsifier (S2), and

the ratio of the total mass of the ionic components (M3) and (S1) to the total mass of the nonionic components (M5) and (S2) used was less than 1.

2. The plastic dispersion of claim 1 having a solids content of 20 to 80% by weight.

3. The plastic dispersion of claim 1, wherein the sum of the proportions of homopolymer or copolymers A and B in the vinyl ester copolymer is from 75 to 100% by weight, based on the total mass of the copolymer.

4. The plastic dispersion of claim 1 having a pH in the range of 2 to 9.

5. The plastic dispersion as claimed in claim 1, wherein the homo-or copolymers A and/or B comprise, incorporated in the form of polymerized units, as vinyl esters of carboxylic acids having from 1 to 8 carbon atoms, vinyl esters of saturated branched monocarboxylic acids having from 9, 10 or 11 carbon atoms in the acid radical, vinyl esters of relatively long-chain saturated and unsaturated fatty acids, vinyl esters of benzoic acid or of p-tert-butylbenzoic acid, and mixtures thereof, vinyl esters of carboxylic acids having from 1 to 18 carbon atoms (M1).

6. The plastic dispersion according to claim 1, wherein the homo-or copolymers A and/or B comprise vinyl acetate incorporated in the form of polymerized units as vinyl esters of carboxylic acids having from 1 to 18 carbon atoms (M1).

7. The plastic dispersion of claim 1, wherein the copolymers a and/or B comprise, incorporated in the form of copolymerized units, monoethylenically unsaturated and optionally halogenated hydrocarbons having 2 to 4 carbon atoms (M2), preferably ethylene.

8. The plastic dispersion of claim 7, wherein the proportion of monoethylenically unsaturated hydrocarbon having 2 to 4 carbon atoms (M2) in the vinyl ester copolymer is less than 20% by weight, based on the total mass of monomers used to prepare the vinyl ester copolymer.

9. The plastic dispersion according to claim 1, wherein the homo-or copolymer A and/or B comprises, incorporated in the form of copolymerized units, as ethylenically unsaturated ionic monomer (M3), an unsaturated monocarboxylic acid, an unsaturated dicarboxylic acid, or a monoester thereof with an alkanol, an unsaturated sulfonic acid and/or an unsaturated phosphonic acid.

10. The plastic dispersion of claim 1, wherein the copolymer derived from monomer composition A or the copolymers derived from monomer compositions A and B comprise up to 10% by weight, based on the total mass of monomers used in the monomer composition, of structural units (M4) derived from at least one unsaturated copolymerizable organosilicon compound.

11. The plastic dispersion of claim 10, wherein the copolymer derived from monomer composition a or the copolymers derived from monomer compositions a and B comprise from 0.1 to 1.5% by weight, based on the total mass of the respective monomer composition, of structural units (M4) derived from at least one unsaturated, copolymerizable organosilicon compound.

12. The plastic dispersion of claim 1, wherein siloxane groups are included and have the general formula RSi (CH)₃)_0-2(OR¹)_3-1The monomer(s) used as unsaturated copolymerizable organosilicon compound (M4), R having the meaning of CH₂＝CR²-(CH₂)_0-1Or CH₂＝CR²-CO₂-(CH₂)_1-3，R¹Is a linear or branched, optionally substituted alkyl radical having 1 to 12 carbon atoms, which may optionally be interrupted by ether groups, R²Is H or CH₃。

13. The plastic dispersion of claim 1, wherein the vinyl ester copolymer comprises up to 30% by weight, based on the total mass of monomers used to prepare the vinyl ester copolymer, of at least one further ethylenically unsaturated monomer (M6) incorporated as copolymerized units.

14. The plastic dispersion of claim 1, which comprises an anionic emulsifier as ionic emulsifier (S1).

15. The plastic dispersion of claim 14, comprising alkali metal and ammonium salts of sulfuric monoesters or phosphoric monoesters of alkyl sulfates, alkyl phosphates, ethoxylated alkanols and ethoxylated alkylphenols, alkanesulfonic acids, alkylarylsulfonic acids and/or compounds of the general formula I as anionic emulsifiers,

wherein R is¹And R²Is hydrogen or C₄-C₂₄-alkyl groups and not both hydrogen, X and Y being alkali metal ions and/or ammonium ions.

16. The plastic dispersion of claim 1, comprising 1 to 8 wt% of a nonionic emulsifier (S2) based on the total mass of monomers used to prepare the vinyl ester copolymer.

17. The plastic dispersion as claimed in claim 1, comprising araliphatic and aliphatic nonionic emulsifiers as nonionic emulsifiers (S2), preferably ethoxylated mono-, di-and trialkylphenols (degree of ethoxylation: 3 to 50, alkyl radical: C4 to C9), ethoxylates of long-chain, branched or linear alcohols (degree of ethoxylation: 3 to 50, alkyl radical: C6 to C36) and polyethylene oxide/polypropylene oxide block copolymers.

18. The plastic dispersion as claimed in claim 17, comprising ethoxylates of long-chain, branched or straight-chain alkanols (alkyl groups C6-C22, average degree of ethoxylation: 3 to 50), particularly preferably ethoxylates based on natural alcohols, guerbet alcohols or oxo alcohols having a straight-chain or branched C12-C18-alkyl group and a degree of ethoxylation of 10 of 8 to 50, as nonionic emulsifiers (S2).

19. The plastic dispersion as claimed in claim 1, wherein the ratio of the total amount of ionic components (M3) and (S1) to the total amount of nonionic components (M5) and (S2) used is a value of from 0.0 to 0.9.

20. The plastic dispersion of claim 1, which comprises protective colloids, preferably polyvinyl alcohols, starch derivatives, cellulose derivatives and vinylpyrrolidone.

21. The plastic dispersion of claim 20 comprising polyvinyl alcohol.

22. A process for producing the plastic dispersion of claim 1, wherein a homopolymer or copolymer B is first prepared by free-radical aqueous emulsion polymerization of a monomer or monomer mixture B, then preparing the homopolymer or copolymer A by free-radical emulsion polymerization of the monomer or monomer mixture A in an aqueous dispersion of the homopolymer or copolymer B, the free-radical emulsion polymerization is carried out in the presence of a nonionic emulsifier (S2), optionally in the presence of an ethylenically unsaturated ionic monomer (M3) and/or an ionic emulsifier (S1), so that the total mass of the nonionic emulsifiers (S2) in the end product is at least 0.5% by weight, the ratio of the total mass of the ionic components (M3) and (S1) used in the end product to the total mass of the nonionic components (M5) and (S2) being less than 1, with the proviso that the preparation of the homopolymer or copolymer B is also carried out after the preparation of the homopolymer or copolymer A.

23. The process according to claim 22, wherein the free-radical emulsion polymerization is carried out in the presence of a protective colloid, in particular in the presence of polyvinyl alcohol.

24. The process of claim 22, wherein the free-radical emulsion polymerization is carried out in the presence of a molecular weight-regulating substance, in particular in the presence of an organosulfur compound, a silane, an allyl alcohol or an aldehyde.

25. Use of the plastic dispersion of claim 1 as an aqueous formulation for coating substrates.

26. Use of the plastic dispersion of claim 1 as a binder in pigmented aqueous formulations.

27. Use of the plastic dispersion of claim 1 as a binder in renders, tile adhesives, coatings, sealing compounds, sealing compositions or paper coating slips in combination with synthetic resins.

28. Use of the plastic dispersion of claim 1 as a binder in emulsion paints.

29. An aqueous formulation for coating a substrate comprising the plastic dispersion of claim 1.

30. An aqueous pigment-containing formulation comprising the plastic dispersion of claim 1.

31. An emulsion paint comprising the plastic dispersion of claim 1.

32. A food coating comprising the plastic dispersion of claim 1.

33. A paper coating slip agent comprising the plastic dispersion of claim 1.