CA2393524A1 - Aqueous primary dispersions and coating matters, a method for producing same and the use thereof - Google Patents

Abstract

The invention relates to aqueous primary dispersions and coating matters containing dispersed and/or emulsified, solid and/or liquid polymer particles and/or dispersed solid core-shell particles having a particle diameter <= 500 nm. The inventive dispersions and coating matters can be produced by means of controlled radical micro or miniemulsion polymerisation of (A) at least one olefinically unsaturated monomer and (B) at least one olefinically unsaturated monomer of the general formula (I): R1R2C=CR3R4, wherein the radicals R1, R2, R3 and R4, independently from each other, stand for hydrogen atoms or substituted or unsubstituted alkyl-, cycloalkyl-, alkylcycloalkyl-, cycloalkylalkyl-, aryl, alkylaryl-, cycloalkylaryl-arylalkyl- or arylcycloalkyl radicals, whereby said last monomer is different from the monomer (A), with the proviso that at least two of the variables R1, R2, R3 and R4 stand for substituted or unsubstituted aryl-, arylalkyl- or arylcycloalkyl radicals, especially substituted or unsubstituted aryl radicals, and in the presence of (C) at least one hydrophobe cross-linking agent for the copolymer resulting from the starting products (A) and (B). The invention also relates to the use thereof.

Description

AQUEOUS PRIMARY ~I~uPL'I~5TON5- AND CQAfi~P'G lotATTERS. A METHOD
FDR S~ ~ y ~ OF
The present invention relates to navel aqueous primary dispersions and coating materials which comprise dispersed and/or emulsified, solid and/or liquid polymer particles and/or dispersed solid core-shell particles having a diameter <_ 500 nm. The present invention further relates to a novel process for preparing the novel aqueous primary dispersions and coating materials by means of controlled free-radical microemulsion and miniemulsion polymerization. The present invention relates, furthermore, to the use of the novel aqueous primary dispersions and coating materials for producing single-coat or multicoat clearcoat systems and single-coat or multicaat color and/or effect paint systems in automotive c7EM finishing and refinishing, industrial coating, including container coating, coil coating and the coating of electrical components, and furniture coating.
Microemulsions and miniemulsions are dispersions comprising water, an oil phase and one or more surface-active substances and having droplet sizes of from 5 to 50 nm (microemulsions) or from 50 to 500 nm.
Microemulsions are regarded as being thermodynamically stable, whereas the miniemulsions are regarded as metastable (cf. Emulsion Polymerization and Emulsion Polymers, Editors: P.A. Lovell and Mohamed S. El-Aasser, John Wiley and Sons, Chichester, New York, Weinheim, 1997, pages 700 et seq.; Mohamed S. E1-Aasser, Advances in Emulsion Polymerization and Latex Technology, 30th Annual Short Course, Volume 3, June 7-11, 1999, Emulsion Polymers Institute, Lehigh University, Bethlehem, Pennsylvania, USA). Both types of dispersions find broad application in the art: for example, in cleaning products, cosmetics or bodycare products. They may, however, also be used for polymerization reactions in place of the customary macroemulsivns, in which droplet sizes > 1000 nm are present.
It would be desirable here to carry out the free-radical polymerization in microemulsion and mini-emulsion by the so-called batch procedure, where the total amount of the monomers is introduced as initial charge in an aqueous medium, emulsified and subsequently polymerized to completion. This would make it possible to avoid from the outset the problems which result from the feed technique. These problems consist in particular in a comparatively high level of expenditure on measurement and control equipment and on apparatus, and in the fact that the monomers being fed in do not arrive at the site of polymerization but instead, as with macroemul.sion polymerization, serve as a monomer reservoir for the initiated monomer droplets.
As a result, these droplets change their composition continuously, which in the case of their subsequent initiation can lead to nonuniformity in the composition of the resultant polymer particles.
The preparation of aqueous primary dispersions by means of free-radical miniemulsivn polymerization is known, for example, from the international patent application WO 98/02466 or from German patents DE-A-196 28 143 and DE-A-196 28 142. In the case of these known processes, the monomers may be copolymeri.zed in the presence of different low molecular mass, oligomeric or polymeric, hydrophobic substances. Furthermore, hydrophobic, organic auxiliaries of low solubility in water, such as plasticizers, enhancers of the tackiness of the resulting film, film-forming auxiliaries or other, unspecified organic additives, may be incorporated into the monomer droplets of the miniemulsion. The use of diphenylethylene as a comvnomer and of hydrophobic crosslinking agents for the copolymers formed from the monomers, and the use of the known aqueous primary dispersions for preparing coating materials, are equally not evident from the abvvementioned patents.
Although the known processes solve the problem of the exothermic nature of the free-radical polymerization and copolymerization to a certain extent, they do so at the expense of an increased level of measurement and control equipment.
Aqueous coating materials based on aqueous primary dispersions which comprise solid cure-shell particles and have been prepared by miniemulsion polymerization of monomers in the presence of hydrapholsic polymers are known from the patents EP-A-0 401 565, WO 97/49739 or EP-A-0 755 946. The use of a diphenylethylene comonomer and copolymerization in the presence of hydrophobic crosslinking agents for the copolymers farmed from the monomers are not disclosed by these patents. Although the known coating m-ater_ials already have numerous advantageous grap-erties, there is still the occurrence of problems associated with inadequate distribution of the crosslinklng agents in the aqueous dispersions. One particular consequence of this is that a larger amount of crosslinking agents has to be used than would be theoretically necessary. Unreacted crosslinking agents may then, in certain ciroumatances, be harmful to the performance properties of the coatings produced from the coating materials.
The micrvencapsulation of hydrophobic organic solvents or of target materials such as biocides and herbicides in water-insoluble core-shell particles produced by miniemulsion polymerization is known from the patents EP-A-0 203 724 or US-A-4,677,003. However, copolymerization is not conducted in the presence of hydrophobic crosslinking agents for the copolymers formed from the monomers. Nor is the use of a diphenylethylene camonomer described.

-The patents EP-A-0 622 389 or DE-A-43 14 297 disclose the copolymerizat.ion of monomers in the presence of blocked polyisacyanates and epoxy resins. However, the technique employed is not that of miniemulsion polymerization. A comparable process, but in which the crosslinking merits are not specified, is disclosed by the patents EP-A-0 758 347 or WO 95/29944. The corresponding known copolymers and their primary dispersions are used for preparing coating materials.
The known caat-ing materials likewise have the problems associated with insufficiently fine distribution of the crosslinking agents in the coating materials.
The free-radical addition polymerization employed to prepare acrylate copolymers is frequently very exothermic and difficult to control. What this means for the reaction regime is that high concentrations of monomers and/or the so-called batch procedure, where the total amount of the monomers is introduced as initial charge in an aqueous medium, emulsified and subsequently polymerized to completion, must be avoided. In addition, the targeted establishment of defined molecular weights, molecular weight distributions and other properties often causes difficulties. The targeted establishment of a defined profile of properties in acrylate copolymers is, however, of great importance for their use as binders in coating materials, especially aqueous coating materials, since by this means it is possible to exert direct influence on the perforraanaE properties profile of the coating materials.
There has th~refvre been no lack of attempts to regulate the free-radical cvpvlymerization of olefinically unsaturated monomers in a targeted way.
For instance, the international patent application WO
98/01478 describes a process in which the copolymerization is conducted in the presence of a free-radical initiator and of a thiocarbonylthio compound as chain transfer agent.
The international patent application WO 92/13903 describes a process for preparing copolymers of low molecular weight by free-radical chain polymerization in the presence of a group transfer agent having a carbon-sulfur double bond. These cornpountis act not only as chain transfer agents but also as growth regulators, and so result only in copolymers of low molecular weight.
The international patent application WO 96/15157 discloses a process for preparing copolymers having a comparatively narrow molecular weight distribution, in which a monomer is reacted with a vinyl-terminated macromonvmer in the presence of a free-radical initiator.

, _ Furthermore, the international patent application WO
98/37104 discloses the preparation of acrylate copolymers having defined molecular weights by free-radical polymerization in the presence of a chain transfer agent having a C-C double bond and having radicals which activate this double bond in respect of .~ the free-radical addition of monomers.
Despite significant progress in this field, there continues to be a lack of a universally applicable process of controlled free-radical polymerization which yields chemically structured polymers, especially acrylate copolymers, in a simple manner and by means of which it is possible to tailor the profile of properties of the polymers in respect of their application in coating materials, especially aqueous coating materials, which are used to produce clearcoats and multicvat color and/or effect paint systems.
It is an object of the present irnrention to find new aqueous primary diapers-ions and coating materials comprising dispersed and/or emulsified, solid and/or liquid polymer particles and/or dispersed solid core-shell particles having a diameter 5 500 nm which no longer have the disadvantages of the prior art but instead can be prepared in a simple and controlled manner. The copolymers present in the new aqueous primary dispersions and coating materials ought to have defined molecular weights and ought to be preparable ' CA 02393524 2002-06-10 inter olio by the batch procedure without the occurrence in this case of the problems associated with the highly exothermic nature of the free-radical polymerization, ranging for instance from the thermal damaging of the products through to runaway of the reactor. Moreover, the new aqueous primary dispersions I~ and coating materials ought to contain very finely distributed crosalinking agents.
A further object of the present invention was to find a new process for pregarinrj aqueous primary dispersions and coating materials by free-radical microemulsion or miniemulsion polymerization which no longer has the disadvantages of the prior art, but can instead be carried out by the batch procedure without the problems described above occurring, and which allows the profile of properties of the resulting copolymers to be adj usted in a targeted way, especially in terms of the molecular weight and molecular weight distribution.
Accordingly, we have found the novel aqueous primary dispersions and dating materials comprising dispersed and/or emulsified, solid and/or liquid polymer particles and/or dispersed solid core-shell particles having a diameter <_ 500 nm, preparable by controlled free-radical microemulsion or miniemulsion poly-merization of A) at least one olefinically unsaturated monomer and B) at least one olefinically unsaturated monomer which is different than the olefinically unsaturated monomer (A) and has the general formula I
R~'RaC-CRaR4 ( I ) in which the radicals Rl, R2, R3 and R4 each independently of one another are hydrogen atoms or .substituted or unsubstituted alkyl, cycloalkyl, alkylcycloalkyl, cycloalkylalkyl, aryl, alkylaryl, cycloalkylaryl arylalkyl or arylcycloalkyl radicals, with the proviso that at least two of the variables R1, R2, R3 and R4 are substituted or unsubstituted aryl, arylalkyl or arylcycloalkyl radicals, especially substituted or unsubstituted aryl radicals;
in the presence of at least C) at least one hydrophobic crosslinking agent for the copolymer result-ing from the starting products (A) and (B) , which are referred to below for short as "primary dispersions of the invention" and, respectively, "coating materials of the invention".

- ~.~ -We have also found the novel process for preparing aqueous primary dispersions and coating materials comprising dispersed and/or emulsified, solid and/or liquid polymer particles and/or dispersEd solid core-s shell particles having a diameter _< 500 nm by controlled free-radical microemulsion yr miniemulsion polymerization of A) at least one olefinical_ly unsaturated monomer and B) at least ane olefinically unsaturated monomer which is different than the olefinically unsaturated monomer (A) and has the general formula I
(I) in which the radicals R1, R2, R3 and R4 each independently of one another are hydrogen atoms or substituted or unsubstituted alkyl, cycloalkyl, alkylcycloalkyl, cycloalkylalkyl, aryl, alkylaryl, cycloalkylaryl arylalkyl or arylcycloalkyl radicals, with the proviso that at least two of the variables Rl, Rz, R3 and R4 are substituted or unsubstituted aryl, arylalkyl or arylcycloalkyl radicals, especially substituted or unsubstituted aryl radicals;
in the presence of at least C) at least one hydrophobic crosslinking agent for the copolymer resulting from the starting products (A) and (B) , which is referred to for short below as "process of the invention".
Further subj ects of the invention will emerge from the following desci-igtian.
In the light of the prior art it was surprising and unforeseeable by the skilled worker that the object on which the present invention was based could be achieved through the primary dispersions of the invention and the coating materials of the invention and also through the process of the invention. In particular, it was surprising that the copolymers present in the primary dispersions of the invention had properties which make them highly suitable for use in coating materials. It was also surprising that the primary dispersions of the invention can be used directly as coating materials, even needing 1e s crosslinking agent than conventional coating materials. Not least, it was surprising that the process of the invention yields the primary dispersions and coating materials of the invention in a particularly simple and targeted manner without the occurrence of the above-des~ibed problems known from the prior art.

For the purgosES of the present invention, the property of being hydrophilic is understood as the constitutional property of a molecule or functional group to penetrate into the aqueous phase or to remain therein. Accordingly, for the purposes of the present invention, the property of being hydrophobic is understood as the constitutional property of a molecule or functional group to exhibit exophilic behavior with respect to water; i.e., they display the tendency not to penetrate into water, or to depart the aqueous phase. For further details, reference is made to R~mpp Lexikon Lacke and Druckfarben, Georg Thieme Verlag, Stuttgart, New York, 1998, "Hydrophilicity", "Hydrophobicity", gages 294 and 295.
In accordance with the invention, the primary dispersions and coating materials comprise dispersed and/or emulsi~ied solid and/or liquid polymer particles 20~ and/or dispersed solid core-shell particles. The size of the polym8r particles or of the dispersed core-shell particles is a direct result of the process of the invention described below. In this case the average particle diameter is less than 500 nm. It is preferably from 10 to 500 nm, more preferably from 50 to 400 nm, and with very particular preference from 100 to 350 nm.
The primary dispersions and coating materials of the invention have an advantageously high solids content of, for example, more than 20~ by weight, preferably more than 30% by weight . It is even possible to obtain solids contents of mere than 40% by weight. The primary dispersions anzl coating materials of the invention have a low viscosity, even at high solids content.
The core-shell particles for use in accordance with the invention result from the graft cvpolymerization of organic solids and the cvmvnomers (A) and (B) for use in accordance with the i~ntivn, described below. Said organic solids are preferably hydrophobic polymers, as described, for example, in the patents EP-A-0 401 565, page 3, line 5 to page 4, line 50, WO 97/49739, page 4, line 19 to page 5, line 3, or EP-A-0 755 946, page 3, line 26 to page 5, line 38. These hydrophobic polymers may also be prepared by the process of the invention.
The primary dispersions and coating materials of the invention may also have a bimvdal particle size distribution in which from 0.1 to 80% by weight, in particular from 1.0 to 50% by weight, of the copolymer resulting from the cvmvnamers (A) and (B) have a particle size, determined using an analytical ultracentrifuge, of from 20 to 500 nm, in particular from 50 to 300 nm, and from 20 to 99.9% by weight, in particular from 50 to 99% by weight, of the copolymer have a particle size of from 200 to 1500 nm, in particular from 300 to 900 nm, said particle sizes differing by at least 50 nm, in particular by at least 100 nm, with very particular preference by at least 200 nm. Concerning the measurement method, reference is made for further details to lines 5 to 9 of page 6 of the German patent application DE-A-196 28 142.
The first st -arcing compound essential to the invention for the primary dispersions or coating materials of the invention, and far the process of the invention, is at least one ole.finically unsaturated monomer (A).
It is preferred here to use at least one monomer (A) comprising reactive functional groups which are able to enter into crvsslinking reactions with the complementary reactive functional groups of the crosslinking agents (C). Examples of suitable complementary reactive functional groups for use in accordance with the invention are collated in the overview below. In the overview, the variable R is an acyclic or cyclic aliphatic radical, an aromatic radical and/or an aromatic-aliphatic (araliphatic) radical; the variables R' and R" are identical or different aliphatic radicals or are linked to one another to form an aliphatic or heteroaliphatic ring.
Overview: lss of c~lfurx~t-i. aal groups Monomer (A) aa~d crass liak~:ng agent ( C ) or C ro s s linkiag agsat ( C ) a~xd mwnvm~err ( A ) -SH -C (O)'-OH
-NHz -C (O) -O-C (O) --OH -NCO
-O- (CO) -NH- (CO) -NH2 -NH-C (O) -OR
-O- (CO) -NHZ -CHZ-OH
>NH - CHz -O - CH3 -NH-C {O) -CH ( -C (O) OR) 2 -NH-C (O) -CH (-C (O) OR) (-C (O) -R) _~_C (0) _~~ R..
=Si (OR) z -CH-CHz -C (O) -OH O
-CH-CHZ
The selection of the resg~ective complementary groups is guided an the one hand by the consideration that, during the strsrage of primary dispersions or coating materials of the invention, these groups do not enter into any unwanted reactions and/or, if appropriate, do not inhibit or disrupt curing with actinic radiation, and on the other hand by the temperature range within which crasslinking is to take place.
,, For the coating materials of the invention it is preferred to employ crosslinking temperatures of from 100°C to 180°C. It is therefore preferred to use monomers (A) containing thio, hydroxyl, alkoxymethylamino, imino, carbamate, allaphanate and/or carboxyl groups, but in particular amino, alkoxymethylamino or hydrr~xyl groups, especially hydroxyl groups, an the one hand, and crosslinking agents (C) containing anhydride, carboxyl, epoxy, blocked isocyanate, urethane, methylol, methylol ether, siloxane, amino, hydroxyl and/or beta-hydroxyalkylamide groups, but especially blocked isacyanate, urethane or methylol ether groups, on the other.
Examples of suitable monomers (A) are a1) substantially acid-group-free (meth)acrylic esters such as (meth)acrylic alkyl or cycloalkyl esters having up to 20 carbon atoms in the alkyl radical, especially methyl, ethyl, propyl, n-butyl, sec-butyl, tart-butyl, hexyl, ethylhexyl, stearyl and lauryl acrylate or methacrylate; cycloaliphatic (meth)acryLic esters, especially cyclohexyl, isobornyl, dicyclopentadienyl, octahydro-4,7-methano-1H-i.ndenernethanol (meth)acrylate or tert-butylcyclohexyl (meth)acrylate; (meth)acrylic oxaalkyl esters or oxacycloalkyl esters such as ethyltriglycol (meth)acrylate and methoxy-oligoglycol (meth)acrylate having a molecular weight Mn of preferably 550, or other ethoxylated and/or progoxylated hydroxyl-free (meth)acrylic acid derivatives. These may contain minor amounts of (meth)aorylic alkyl or cycloalkyl esters of .higher functionality, such as the di(meth)acrylates of ethylene glycol, propylene glycol, diethylene glycol, digropylene glycol, butylene glycol, 1,5-pentanediol, 1,6-hexanediol, octahydro-4,7-methano-1H-indenedimethanol or 1,2-, 1,3- or 1,4-cyclohexanediol; trimethylolprvpane di- or tri(meth)acrylate; or pentaerythritol di-, tri- or tetra (meth) acrylate . For the purposes of the present irrv~ention, minor amounts of monomers of higher functionality in this case are to be understood as amounts which do not lead to crosslinking or gelling of the copolymers (A).
a2) Monomers which carry per molecule at least one hydroxyl, amino, alkoxymethylamino or imino group and are substantially free from acid groups, such as hydroxyalkyl esters of acrylic acid, methacrylic acid or another alpha,beta-- L~ -olef.inically unsaturated carboxylic acid, which derive from an alkylene glycol esterified with the acid, or which are obtainable by reacting the alpha, beta-olefinical_ly unsaturated carboxylic acid with an alkylene oxide, especially hydroxyalkyl esters of acrylic acid, methacrylic acid, ethacrylic~acid, crotonic acid, malefic acid, fumaric acid or itacvnic acid in which the hydroxyalkyl group contains up to 20 carbon atoms, such as 2-hydraxyethyl, 2-hydrvxyprapyl, 3-hydrvxygrvpyl, 3-hydroxybutyl, 4-hydrvxybutyl acrylate, msthacrylate, ethacrylate, crvtonate, maleate, fumarate or itaconate; or hydrvxy-cycloalkyl esters such as 1,4-bis(hydrvxy-methyl)cyclohexane, octahydra-4,7-methano-1H-indenedimethanol or methylprvpanediol mono-acrylate, monamethacrylate, monaethacrylate, mvnocratarrate, monvmaleate, mvnofumarate or mvnoitacrsnate; or reaction grvducts of cyclic esters, such as epsilon-caprolactvne, for example, and these hydroxyalkyl or hydroxycycloalkyl esters; or olefinically unsaturated alcvhols such as allyl alcohol or polyvls such as trimethylolprvgane mvnoallyl or diallyl ether or pentaerythritol monoallyl, diallyl or triallyl ether (as far as these monomers (a2) of higher functionality are concerned, the comments made above relating to the monomers (al) of higher functionality apply analogously); N,N-dimethyl-' CA 02393524 2002-06-10 aminoethyl acrylate, N,N-diethylaminc~ethyl meth acrylate, allylamine or N-methyliminoethyl acrylate or N,N-di(methoxymethyl)aminoethyl acryl ate and methacrylate or N,N-di(butoxy methyl)aminoprapyl acrylate and methacrylate;
a3) monomers which carry per molecule at least one acid group which can be converted into the corresponding acid anion group, such as acrylic acid, methacrylic acid, ethacrylic acid, crotonic acid, malefic acid, fumaric acid or itacanic acid;
olefinically unsaturated sulfonic or phosphanic acids or theix partial esters; or mono(meth)acx~yloyloxyethyl maleate, succinate or phthalate. For the purposes of the present invention the mr~nomers (a3) are not used as the sole monomers (A) but are always used in conjunction with other monomers (A) and, moreover, in amounts so small that the monomers (a3) do not polymerize outside the droplets of the miniemulsion.
a4) Vinyl esters of alpha-branched m~nvcarboxylic acids having 5 to 18 carbon atoms in the molecule.
The branched manocarboxylic acids can be obtained by reacting formic acid or carbon monoxide and water with olefins in the presence of a liquid, strongly acidic catalyst; the olefins may be cracking products of paraffinic hydrocarbons, such as mineral oil fractions, and may comprise both branched and straight-chain acyclic and/or cycloaliphatic olefins. The reaction of such olefins with formic acid or, respectively, with carbon monoxide and water produces a mixture of carboxylic acids in which the carboxyl groups are located predominantly on a quaternary carbon atom.
Examples of other olefinic starting materials are propylene trimer, propylene tetramer and diisobutylene. Alternatively, the vinyl esters (a4) may be prepared in cvrmentional manner from the acids, by reacting, for example, the acid with acetylene. Particular preference, owing to their ready availability, is given to using vinyl esters of saturated aliphatic monvcarbaxyl.ic acids having 9 to 11 carbon atoms that are branched on the alpha carbon atom, but especially Versatic~ acids.
a5) Reaction products of acrylic acid and/or methacrylic acid with the glycidyl ester of an alpha-branched monocarbaxylic acid having from 5 to 18 carbon atoms per molecule, in particular a Versatic~ acid, or, instead of the reaction product, an equivalent amount of acrylic and/or methacrylic acid which is then reacted during or after the polymerization reaction with the glycidyl ester of an alpha-branched mvnvcarboxylic acid having 5 to 18 carbon atoms per molecule, especially a Versatic~ acid.

a6) Cyclic and/or acyclic olefins such as ethylene, propylene, 1-butane, 1-pentane, 1-hexane, cyclohexene, cyclopentene, narbornene, butadiene, isoprene, cyclopentadiene and/or dicyclo-pentadiene.
a7) (Meth)acrylamides such as (meth)acrylamide, N-methyl-, N,N-dimethyl-, N-ethyl-, N,N-diethyl-, N-prc~pyl-, N,N-dipropyl-, N-butyl-, N,N-dibutyl-, ,N-cyclohexyl-, N,N-cyclohexylmethyl- and/or N-methylol-, N,N-dimethylol-, N-methvxymethyl-, N,N-di(methoxymethyl)-, N-ethoxymethyl- and/or N,N-di(ethaxyethyl)-(meth)acrylamide;
a8) monomers containing epoxide groups, such as the glycidyl ester of acrylic acid, methacrylic acid, ethacrylic acid, crr~tonic acid, malefic acid, fumaric acid and/or itaconic acid.
a9) Vinylarvmatic hydrocarbt3ns such as styrene, alpha-alkylstyrenes, especially alpha-methylstyrene, and/or vinyltoluene; vinylbenzoic acid (all isomers), N,N-diethylaminQStyrene (all isomers), alpha-methylvinylbenzoic acid (all isomers), N,N-diethylamino-alpha-methylstyrene (all isomers) and/or p-vinylbenzenesulfonic acid.
a10) Nitriles such as acrylonitrile and/or meth-acryloni :rile.
all) Vinyl compounds, especially vinyl halides and/or vinylidene dihalide such as vinyl chloride, vinyl fluoride, vinylidene dichloride or vinylidene difluoride; N-vinylamides such as vinyl-N-methylformaraide, N-vinylcaprolactam, 1-vinyl-imidazvle or N-vinylpyrrolidone; vinyl ethers such as ethyl vinyl ether, n-propyl vinyl ether, l0 isopropyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether and/or vinyl cyclohexyl ether; and/or vinyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl pivalate and/or the vinyl ester of 2-methyl-2 ethylhept-anoic acid.
a12) Allyl compounds, especially allyl ethers and allyl esters such as allyl methyl, ethyl, propyl or butyl ether or allyl acetate, propionate or butyrate.
a13) Polysiloxane maoromonomers having a number-average molecular weight Mn of from 1000 to 40,000 and having on average from 0.5 to 2.5 ethylenically unsaturated double bands per molecule; especially polysilaxane macromonomers having a number-average molecular weight Mn of from 2000 to 20,000, with particular preference from 2500 to 10,000 and, in particular, from 3000 to 7000 and having on average from 0.5 to 2.5, preferably from 0.5 to 1.5, ethylenically unsaturated double bonds per molecule, as are described in DE-A-38 07 571 on pages 5 to 7, in DE-A-37 06 095 in columns 3 to 7, in EP-H-0 358 153 on pages 3 to 6, in US-A-4,754,014 in columns 5 to 9, in DE-A-44 21 823 or in the international patent application WO
92/22615 on page 12, line 18 to page 18, line 10.
and/or a14) Acryloyloxysilane-containing vinyl monomers, preparable by reacting hydroxy-functional silanes with epichlorohydrin and then reacting the reaction product with (meth)acrylic acid and/or hydroxyalkyl and/or hydroxycycloalkyl esters of (meth)acrylic acid (cf. monomers a2).
Each of the abovementTOned manomers (al) to (a14), with the exception of the monomer (a3), can be polymerized alone with the monomers (B). In accordance with the invention, however, it is advantageous to use at least two monomers (A), since by this means it is possible to vary the profile of properties of the resulting copolymers very widely, in a particularly advantageous manner, and to tailor said profile of properties very targetedly to the particular intended use of the primary dispersions of the invention or of the coating materials of the invention.

Further examples of suitable manam~rs (A) are disclosed in the German patent application DE-A-196 28 142, page 2, line 50 to page 3, line 7.
Preferably, the monomers (A) are selected so as to give (meth)acrylate cagolymers whose profile of properties is determined primarily by the (meth)acrylates described above. In that case it is preferred as comanamer (A) to use vinylaramatis hydrocarbons (a9), especially styrene.
The second starting products, essential to the invention, far preparing the primary dispersions and coating materials of the invention and far the process of the invention is at least one olefinically unsaturated monomer (B) which is different than the above-described monomers (A).
The olefinically unsaturated monomer (B) for use in accordance with the invention has the general formula I
In the general formula I, the radicals R1, Rz, R3 and R4 each independently of one another are hydrogen atoms or substituted or unsubstituted alkyl, cycloalkyl, alkylcycloalkyl, cycloalkylalkyl, aryl, alkylaryl, cycloalkylaryl arylalkyl or arylcycloalkyl radicals, with the proviso that at least two of the variables Rl, R2, R3 and R4 are substituted or unsubstituted aryl, arylalkyl or arylcycloalkyl radicals, especially substituted or unsubstituted aryl radicals.
Examples of suitable alkyl radicals are methyl, ethyl, propyl, isaprapyl, n-butyl, isobutyl, tart-butyl, amyl, hexyl or 2-ethylhexyl.
Examples of suitable cycloalkyl radicals are cyclobutyl, cyclogentyl or cyclohexyl.
Examples of suitable alkylcycloalkyl radicals are methylenecyclohexane, ethylenecyclohexane or propane-1,3-diylcyclohexane.
Examples of suitable cycloalkylalkyl radicals are 2-, 3- or 4-methyl-, -ethyl-, -propyl- or -butylcyclohex-1-y1.
Examples of suitable aryl radicals are phenyl, naphthyl or biphenylyl, preferably phenyl and naphthyl, and especially phenyl.
Examples of suitable alkylaryl radicals are benzyl or ethylene- ar propane-1,3-diylbenzene.
Examples of sui-table cycloalkylaryl radicals are 2-, 3-or 4-phenylcyclohex-1-yl.
Examples of suitable arylalkyl radicals are 2-, 3- or 4-methyl-, -ethyl-, -propyl- or -butylphen-1-yl.
Examples of suitable arylcycloalkyl radicals are 2-, 3-or 4-cyclohexylphen-1-yl.
The above-des~ril;sed radicals Rl, R2, R3 and R4 may be substituted. For this purpose it is possible to use electron-withdrawing or electron-donating atoms or organic radicals.
Examples of suitable substituents are halogen atoms, especially chorine and fluorine, nitrile groups, nitro groups, partially or fully halogenated, especially chlorinated and/or fluorinated, alkyl, cycloalkyl, alkylcycloalkyl, cycloalkylalkyl, aryl, alkylaryl, cycloalkylaryl arylalkyl and arylcycloalkyl radicals, including those exemplified above, especially tert-butyl; aryloxy, alkyloxy and cycloalkyloxy radicals, especially phenoxy, naphthoxy, methoxy, ethoxy, propoxy, butyloxy or cyclohexyloxy; arylthio, alkylthio and cycloalkylthio radicals, especially phenylthio, naphthylthio, methylthio, ethylthio, propylthio, butyl-thio or cyclohexylthio; hydroxyl groups; and/or primary, secondary and/or tertiary amino groups, especially amino, N-methylamino, N-ethylamino, N-propylamino, N-phenylamino, N=cyclohexylamino, N,N-dimethylamino, N,N-diethylamino, N,N-dipropylamino, N,N-diphenylamino, N,N-dicyclohexylamino, N-cyclohexyl-N-methylamino yr N-ethyl-N-methylamino.

Examples of monomers (B) used with particular preference in accordance with the invention are diphenylethylene, dinaphthaleneethylene, cis- or trans-stilbene, vinylidenebis(4-N,N-dimethylaminobenzene), vinylidenebis(4-aminobenz~ne) or vinylidenebis(4-nitrobenzene) .
In accordance with the invention, the monomers (B) may be used individually or as a mixture of at least two monomers (B).
The proportion of the monomers (B) in the monomer mixture (A) and (B), based in each case on the mixture, is preferably from 0.01 to 10%, mare preferably from 0.1 to 9.0%, with particular preference from 0.15 to 8.0%, with very particular preference from 0.2 to 7.0%, and in particular from 0.25 to 6.0% by weight.
As regards the reaction regime and the properties of the resulting copolymers, especially the acrylate copolymers, diphenylethylene is of very particular advantage and is therefore used with very particular preference in accordance with the invention.
The monomers (A) and (B) to be used in accordance with the invention are reacted with one another to form copolymers in the presence of at least one water-soluble and/or oil-soluble initiator which forms free radicals. Examples of initiators which can be used are:
dialkyl peroxides, such as di-tart-butyl peroxide or dicumyl peroxide; hydropervxides, such as cumene hydroperoxide yr tart-butyl hydropervxide; peresters, such as tart-butyl perberizaate, tart-butyl perpivalate, tart-butyl per-3,5,5-tr.imethylhexan~ate yr tart-butyl per-2-ethylhexanoate; pervxvdicarbanates; potassium, sodium or ammonium peroxvdisulfate; azo initiators, examples being azvdinitriles such as azobisisvbutyro-nitrile; C-C-cleaving initiators such as ben~pinacol silyl ethers; or a combination of a nonvxidizing initiator with hydrogen peroxide. Further examples of suitable initiators are des~:ribed in the German patent application DE-A-196 28 142, page 3, line 49 to page 4, line 6. Combinations of these initiators may also be used.
It is preferred to add comparatively large amounts of free-radical initiator, the proportion of the initiator in the reaction mixture being, based in each case on the overall amount of the monomers (A) and of the initiator, with particular preference from 0.2 to 20~
by weight, with very particular preference from 0.5 to 15~s by weight, and in particular from 1.0 to 10~ by weight.
The weight ratio of initiator to the monomers (B) is preferably from 5:1 to 1:20.

The monomers (A) and (B) are, in accordance with the invention, cvpolymeri.zed in the presence of at least one hydrophobic crosslinking agent. The hydrophobic crosslinking agsrrts preferably cr~ntain the above-described reactive functional groups which undergo crosslinking reactions with the complementary reactive functional groups gre~ent in the resultant copolymers.
Examples of especially suitable crosslinking agents (C) are blocked polyisocyanates, tris(alkoxycarbonyl amino)triazines or fully etherified amino resins.
Examples of suitable blocking agents for preparing the blocked polyi ocyanates (C) are the blocking agents known from the U.S. patent US-A-4,444,954:
i) phenols such as phenol, cresol, xylenol, nitrophenol, chlorophenol, ethylphenol, t-butyl phenol, hydroxybenzaic acid, esters of these acids, or 2,5-di-tert-butyl-4-hydroxytoluene;
ii) lactams, such as s-caprolactam, 8-valerolactam, y-butyrolactam or ~i-prapiolactam;
iii) active methylenic compounds, such as diethyl malonate, dimethyl malonate, ethyl or methyl acetoacet-ate, or acetyl acetone;
iv) alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, t-butanol, n-amyl alcohol, t-amyl alcohol, lauryl alcohol, ethylene glycol manomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol mvnamethyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether, methoxymethanol, glycolic acid, glycolic esters, lactic acid, lactic esters, methylolurea, methylolmelamine, diacetone alcohol, ethylenechlc~rohydrin, ethylenebromvhydrin, 1,3-dichloro-2-propanol, 1,4-cyclohexyldimethanol or acetocyanohydrin;
v) mercaptans such as butyl mercagtan, hexyl mercaptan, t-butyl mercaptan, t-dodecyl mercaptan, 2-mercapt~benzathiazole, thiophenol, methylthio-phenol yr ethylthiophenol;
vi) acid amides such as acetaanilide, acetoanisidine amide, acrylamide, methacrylamide, acetamide, stearamide ar benzamide;
vii) imides such as succinimide, phthalimide or maleimide;
viii)amines such as diphenylamine, phenylnaphthylamine, xylidine, N-phenylxylidine, carbazole, aniline, naphthylamine, butylamine, dibutylamine or butylphenylamine;

ix) imidazoles such as imida-zole or 2-ethylimidazole;
x) ureas such as urea, thiourea, ethyleneurea, ethylenethiourea or 1,3-diphenylurea;
xi) carbamates such. as phenyl N-phenylcarbamate or 2-oxazolidone;
xii) imines such as ethyleneimine;
xiii)~oximes such as acetone axime, formaldoxime, acetaldoxime, acetoxime, methyl ethyl ketoxime, diisobutyl ketoxime, diacetyl monoxime, berrzophenone oxime or chlarohaxanane oximes;
xiv) salts of sulfurous acid such as sodium bisulfite or potassium bisulfite;
xv) hydroxamic esters such as benzyl meth-acrylohydroxamate (BMH) or allyl meth-aorylohydroxamate; or xvi) substituted pyrazoles, especially dimethyl-pyrazole, or triazoles; and also xvii)mixtures of these blocking agents, especially dimethylpyrazole and tr:iazvles, malonic esters and acetoacetic esters or dimethylpyrazole and succinimide.
Examples of suitable organic polyisocyanates for blocking are in particular the so-called paint polyisvcyanat~s having isocyanate groups attached to aliphatic, cycloaliphatic, araliphatic and/or aromatic structures. Preference is given to polyisocyanates having from 2 to 5 isocyarrate groups ger molecule and having viscosities of from 100 to 10,000, preferably from 100 to 5000.
Further examples of suitable polyisocyanates for blocking are described in "Methoden der organischen Chemie", Houben-Weyl, Volume 14/2, 4th edition, Georg Thieme Verlag, Stuttgart 1963, pages 61 to 70, and by W. Siefken, Liebigs Annalen der Chemie, Volume 562, pages 75 to 136. Examples of these suitable are the polyurethane grepolymers containing isocyanate groups, which can be prepared by reacting polyols with an excess of polyisvcyanates and which are preferably of low viscosity.
Further examples of suitable polyisocyanates far blocking are polyisocyanates containing isocyanurate, biuret, allophanate, iminvvxadiazinedione, urethane, urea and/or uretdione groups. Polyisocyanates containing urethane groups, for example, are prepared by reacting some of the isocyanate groups with polyols, such as trimethylolgropane and glycerol, for example.

Preference is given to the use of aliphatic or cycloaliphatic polyisocyanates, especially hexamethylene diisocyanate, dimerized and trimerized hexamethylene di.isocyanate isophorone diisocyanate, dicyclohexyl-methane 2,4'-diisocyanate, dicyclohexyl-methane 4,4'-diisocyanate, diisocyanates derived from dimeric fatty acids, as markete3 under the commercial designation DDI 1410 by Henkel and described in patents DO 97/49745 and WO 97/49747, especially 2-heptyl-3,4-bis(9-isocyanatononyl)-1-pentylcyclohexane; or 1,2-, 1,4- or 1,3-bis(isocyanatomethyl)cyclohexane, 1,2-, 1,4- or 1,3-bis(2-isocyanatoeth-1-yl)cyclohexane, 1,3-bis(3-isocyanatoprop-1-yl)cyclohexane or 1,2-, 1,4- or 1,3-bis(4-isocyanatobut-1-yl)cyclohexane, 1,8-diiso-cyanato-4-isocya~ratomethyloctane, 1,7-diisocyanato-4-isocyanatamethylheptane or 1-isocyanato-2-(3-iso-cyanatagrapyl)cyclohexane, or mixtures of these polyisocyanates.
Very particular preference is given to the use of mixtures of polyisocyanates containing uretdione and/or isocyanurate groups and/or allophanate groups based on hexamethylene diisocyanate, as are formed by catalytic oligomerization of hexamethylene diisocyanate using appropriate catalysts.
Examples of particularly highly suitable amino resins (C) are melamine resins, guanamine resins or urea resins. In this context it is possible to use any amino resin that is suitable fr~r clearcaats, or a mixture of such amino resins. For further details refer to Rampp Lexikon Lacke and Druckfarben, Gearg Thieme Verlag, 1998, page 29, "Amino resins", and the textbook "Lackadditive" by Johan Bieleman, Wiley-VCH, Weinheim, New York, 1998, pages 242 ff . , or to the book "Paints, ..
Coatings and Solvents", second completely revised edition, editors: D. Stoye and W. Freitag, Wiley-VCH, Weinheim, New York, 1998, pages 80 ff. Also suitable are the customary and known amino resins some of whose methylol and/or methoxymethyl groups have been defunctionalized by means of carbamate or allophanate groups. Crosslinking agents of this kind are described in the patent s US-A-4,710,542 and EP-B-0 245 700 and also in the article by B. Singh and coworkers "Carbamylmethylated Melamines, Novel Crosslinkers for the Coatings Industry" in Advanced Organic Coatings Science and Technology Series, 1991, Volume 13, pages 193 to 207.
The particularly highly suitable tris-(alkoxycarbanylanrino)triazines had the following formula:

H H
N N N
R 0 C '~ / I ~C OR
N !N 0 N
H 'r ~''' C OR

Examples of particularly highly suitable tris(alkoxy-carbanylamino)tziazines are described in the patents US-A-4,939,213, US-A-5,084,541 or EP-A-0 624 577. Use is made in particular of the tris(methaxy-, tris(butaxy- and/or tris(2-ethylhexaxycarbvnylamino)-triazines.
The methyl butyl mixed esters, the butyl 2-ethylhexyl mixed esters and the butyl esters are of advantage.
They have the advantage over the simple methyl ester of better solubility in polymer melts and also have a lower tendency to crystallize out.
Of the crasslinking agents (C) described above, the blocked polyisacpanates Qffer particular advantages and are therefore usEd with very particular preference in accordance with the invention.
In the process of the i~ntion, the ratio of the monomers (A) comprising complementary reactive functional groups to the crosslinking agents (C) may vary very widely. In accordance with the invention it is of advantage if the molar ratio of complementary reactive functional groups in (A) to complementary reactive functional groups in (C) is from 5.0 . 1.0 to 1.0 . 5.0, preferably from 4.0 . 1.0 to 1.0 . 4.0, with particular preference from 3.0 . 1.0 to 1.0 . 3.0, and in particular from 2.0 . 1 to 1 . 2Ø Particular advantages result if the molar ratio is apgraximately or precisely 1.0 . 1Ø
In addition to the hydrophobic crosslinking agents (C) for use in accordance with the invention and described above, the cvpolymerzzation of the monomers (A) and (B) to be used in accordance with the invention may also be accompanied by hydrophobic compounds (D) which differ from (C). These hydrophobic compounds (D) are also referred to by those in the art as costabilizers.
The hydrophobic compounds (D) comprise water-insoluble polymers, ol.igomers or substances of low molecular mass. Examples of suitable hydrophobic compounds (D) are esters of alpha, beta-monoolefinically unsaturated carboxylic acids, having 3 to 6 carbon atoms, with alcohols having 12 to 30 carbon atoms in the alkyl radical; esters of vinyl alcohol and/or allyl alcohol with alkanemonacarboxylic, -sulfonic and/or -phosphonic acids having 12 to 30 carbon atoms in the molecule;
amides of alpha, beta-monoolefinically unsaturated carboxylic acids having 3 to 6 carbon atoms with alkylamines having 12 to 30 carbr~n atoms in the alkyl radical; macromonomers based on olefinically unsaturated compounds having on average at least one olefinically unsaturated group, in particular at least one terminal olefinical_ly unsaturated group, in the molecule; polysilaxane macramonomars having on average at least one olefvinically unsaturated group, in particular at least one terminal olefinically unsaturated grr~up, in the molecule; oligameric and/or polymeric products of addition polymerization, polycondensation and/or polyaddition; water-insoluble molecular weight regulators, especially mercaptans;
aliphatic, cycloaliphatic and/or aromatic halogenated and/or nonhalogenated hydrocarbons; alkanols and/or alkylamines having at least 12 carbon atoms in the alkyl radical; arganosilanes and/or organosiloxanes;
vegetable, animal, semisynthetic and/or synthetic oils;
hydrophobic dyes. Further examples of suitable hydrophobic crsmpr~unds (D) yr costabilizers (D) , and the amounts in which they are advantageously used, are disclosed in the German patent application DE-A-196 28 142, page 4, lines 37 to 59.
The monomers (A) and (B) for use in accordance with the invention may further be copolymerized in the presence of emulsifiers and/or protective colloids (E). Examples of suitable emul ifiers and/or protective colloids (E), and the amounts in which they are advantageously used, are disclosed in the German patent application DE-A-196 28 142, page 3, lines 8 to 48.
In terms of the molecular weight distribution, the copolymer farmed from the cvmonvmers (A) and (B) is not subject to any restrictions whatsoever. Advantageously, however, the copolymeri.zation is conducted so as to result in a molecular weight distribution Mw/Mn, measured by gel permeation chromatography using polystyrene as standard, of <_ 12, with particular preference S 10, and in particular <_ 7. The molecular weights of the constituents (A) are controllable within wide ranges by the choice of the ratio of monomer (A) to monomer (B) to free-radical initiator. In this relationship, the amount of monomer (B) is a particular determinant of the molecular weight, Specifically such that the higher the fraction of monomer (B) the lower the molecular weight obtained.
Suitable reactors for the copolymerization processes are the customary and known stirred vessels, cascades of stirred vessels, tube reactors, loop reactors or Taylor reactors, as described, for example, in the patents DE-B-1 071 241, EP-A-0 498 583 or in the article by K. Kataoka in Chemical Engineering Science, Volume 50, No. 9, 1995, pages 1409 to 1416. The free-radical cvpolymerization is grefsrably conducted in stirred vessels or Taylor reactors, the Taylor reactors being configured such that the conditions of Taylor flow are met over the entire 7.ength of the reactor, even if the kinematic viscosity of the reaction medium alters greatly - in particular, increases - as a result of the copolymex-ization.
In accordance with the invention, the c~polymerization is conducted in an aqueous medium.
The aqueous medium contains essentially water. Besides the crosslinking agents (C) described in detail above and also any hydrophobic compounds (D) and/or emulsifiers and/or protective colloids (E) the aqueous medium may comprise customary and known coatings additives (F) and/or other dissolved solid, liquid or gaseous, organic and/or inorganic substances of low and/or high molecular mass, provided these do not adversely affect, let alone inhibit, the copolymerization. For the purposes of the present invention, the term "miner amount" means an amount which does not destroy the aqueous nature of the aqueous medium.
Alternatively, the aqueous medium may simply consist of water.
The copolymerization is advantageously conducted at temperatures above room temperature, preference being given to the choice of a temperature range of from 30 to 95°C, with very particular preference from 50 to 90°C.

When using particularly volatile monomers (A) and/or (B) the capolymerization may also be conducted under pressure, preferably under from 1.5 to 3000 bar, with particular preference from 5 to 1500 and, in particular, from 10 to 1000 bar. In specific cases, temperatures higher than 95°C may be used here.
It proves here to be a particular advantage of the process of the invention that it can also be conducted in batch mode. Otherwise, use may also be made of the regimes described in the German gatent application DE-A-196 28 142, page 4, lines 6 to 36.
In accordance with the invention, the copolymerization is conducted in a microemulsion or miniemulsion, in particular a miniemulsion. In this case the average particle diameter of the emulsified monomer droplets is below 500 nm. It is preferably from 10 to 500 nm, more preferably from 50 to 400 nm, and with very particular preference from 100 to 350 nm. The particle diameter is the so-called z-average particle diameter, which is determined by means of photon correlation spectroscopy in accordance with the principle of dynamic, quasielastic light scattering. Far this purpose use may be made, far example, of a Coulter N4 Plus Particle Analyzer from Coulter Scientific Instruments or a PC5 Malvern Zetasizer 1000. The measurement is normally made on an aqueous emulsion containing 0.01 by weight of the emulsified monome-r droplets. The aqueous emulsion further comprises, in the aqueous phase, the corresponding monomers in dissolved form (up to saturation), so that the emulsified monomer droplets do not break up.
The process of the invention may be performed so as to give the bimodal particle size distribution described above. Methods of producing bimodal particle size distributions are customary and known in the technological field in question here. It is preferred to use the seed method described in the German patent application DE-A-196 28 142, page 5, lines 31 to 49.
The preparation of the miniemulsion as part of the process of the irmention has no particular features as to method, but instead takes place in accordance with the customary and known methods of dispersing or emulsifying in a high shear field. Examples of suitable methods are described in the patents DE-A-196 28 142, page 5, lines 1 to 30, DE-A-196 28 143, page 7, lines to 58, or EP-A-0 401 565, [lacuna] lines 27 to 51.
An essential advantage of the primary dispersions of the invention is that they can be used per se as 25 coating materials of the invention, preferably as surfacers, solid-color topcoat, aqueous basecoat and clearcoat materials, in particular as clearcoat materials. For these end uses; at least one customary and known coatings additive (F) in effective amounts may be added to the primary dispersions of the invention before, during and/or after their preparation. Before or during the preparation of the primary disgers-ivns of the invention, the only coatings additives (F) added are those which do not disrupt, or even totally inhibit, the miniemulsion polymerization.
The general technical knowledge of the skilled worker allows him or her to identify such additives (F).
Preferably, said additives (F) are added after the preparation of the primary dispersions of the invention.
Examples of suitable coatings additives (F) are pigments, as described in Rompp Lexikon Lacke and Druckfarben, Gearg Thieme Verlag, 1998, pages 176, "Effect pigments" ; pages 380 and 381 "Metal oxide-mica pigments" to "Metal pigments"; pages 180 and 181, "Iron blue pigments" to "Black ixon oxide"; pages 451 to 453, "Pigments" to "Pigment volume concent-ratibn"; page 563, "Thioindigo pigments"; and page 567, "Titanium dioxide pigments". These additives (F) are used when the coating materials of the invention are used as surfacers, solid-color topcoats or aqueous basecoats, but in particular as aqueous basec~ats in the context of the so-called wet-on-wet technique (cf., for example, European patent 0 089 497), to produce multicoat color and/or effect paint systems.
Further examples of suitable coatings additives (F), which may be used both in the pigmented paints and in the unpigmented coating materials, are oligomeric and polymeric, thermally curable, linear and/or branched poly(meth)acrylates or acrylate copolymers of block, comb and/or random structure, especially those described in the patent DE-A-197 36 535, polyesters, especially those described in the patents DE-A-40 09 858 or DE-A-44 37 535, alkyds, acrylated polyesters, polylactones, polycarbonate~, polyethers, epoxy resin-amine adducts, (meth)acrylate diols, partially hydrolyzed polyvinyl esters, polyurethanes and acrylated polyurethanes, as described in the patents EP-A-0 521 928, EP-A-0 522 420, EP-A-0 522 419, EP-A-0 730 613 or DE-A-44 37 535, or polyureas.
Further examples of suitable coatings additives (F) are organic and inorganic fillers, thermally curable reactive diluents, low-boiling and/or high-boiling organic solvents ("long solvents"), W absorbers, light stabilizers, free- radical scavengers, thermally labile free-radical initiators, crosslinking catalysts, devolatilizers, slip additives, polymerization inhibitors, defoamers, emulsifiers, wetting agents, adhesion promoters, leveling agents, film-forming auxiliaries, theology control additives, or flame retardants. Further examples of suitable coatings additives are described in the textbook "Lackadditive"
by Johan Bieleman, Wiley-VCH, Weinheim, New York, 1998.

If the coating materials of the invention are to be curable with actinic radiation as well (dual cure), they comprise additives (F) curable with actinic radiation. Said actinic radiation may comprise electx-omagnetic radiation such as near infrared (NIR), visible light, W light or X-rays, yr corpuscular radiation such as electron beams. Examples of suitable additives (F) curable with actinic radiation are known from German patent DE-C-197 09 467.
In terms of method, the application of the coating materials of the imrention has no special features, but instead can be carried out by all customary application methods, such as spraying, knife coating, brushing, flow coating, dipping, trickle coating yr roller coating, for example. It is preferred to use spray application methods, such as, for example, compressed air spraying, airless spraying, high-speed rotation, electrostatic spray application (ESTA), alone or in conjunction with hDt spray application such as hot air spraying, for example.
Suitable coating substrates are all surfaces which are not damaged by curing of the coatings present on them with application of heat; examples include metals, plastics, wood, ceramic, stone, textile, fiber composites, leather, glass, glass fibers, glasswool and rockwool, mineral-bound and resin-bound building materials, such as plasterboard and cement slabs or roof shingles, and also assemblies of these materials.
Accordingly, the coating material of the invention is also suitable for applications outside of automotive finishing, especially in the coating of furniture and in industrial coating, including coil coating, container coating and the impregnation or coating of electrical components. In the context of industrial coatings, it is suitable for coating virtually all parts for private or industrial use, such as radiators, domestic appliances, small metal parts such as nuts and bolts, hub caps, wheel rims, packaging, or electrical components such as motor windings or transformer windings.
In the case of electrically conductive substrates it is possible to usa primers produced in a customary and known manner from electrodeposition (ED) coating materials. Suitable for this purpose are both anodic (AED) and cathodic (CED) electrodeposition coating materials, but especially CED. Unfunctivnalized and/or apolar plastic surfaces can be subjected to conventional pretreatment before coating, such as with a plasma or by flaming, or may be provided with an aqueous primer.
The method of curing the applied coating materials of the invention also has no special features, but instead takes place in accordance with the customary and known thermal methods such as heating in a circulating air oven or irradiation with IR lamps, which in the case of dual cure may be supplemented by exposure to actinic radiation. In this context it is possible to use radiation sources such as high-pressure or low-pressure mercury vapor lamps, which may be doped with lead in order to open up a radiation window up to 405 nm, or 1 electron beam sources.
The resultant coatings of the invention, especially the single-coat or multicoat color and/or effect paint systems and clearcoat systems of the invention, are easy to produce and have outst-anding optical properties and very high chemical resistance and weathering stability. Accordingly, the substrates of the invention, comprising at least one coating of the invention, are also of particularly high service value and have a particularly long service life, which makes them particularly attractive, economically and technically, far producers and users.

Examples Examp.l~s 1 to 4 The greparativn cf primaxg dispsrs~rs of the invention and of cog as~t~eri:als of the izxventiaa by the process's of th8 i~vex~tion For carrying out Examples 1 to 4, first of all an emulsifier was di solved in water. Then olefinically unsaturated monomers (A), diphenylethylene (B), a blocked polyisvcyanate (C), and an oil-soluble initiator were mixed with one another. The resultant organic solution was converted into a milky emulsion using an Ult~atuzrax at room t~nperature aver the course of 40 seconds. The resultant preemulsians were stable for s8veral minutes, i.e., they did not exhibit phase separation and hence could be processed further to finely divided miniemulsions without problems by means of a high-pressure homogenizing apparatus. For preparing the miniemuls-ions of Examples 1 to 4 the individual preemulsions were introduced into the storage vessel of a pressure release homagenizer and were emulsified under maximum pressure in circulation mode with cooling far 10 minutes. Following emulsification, the miniemulsions of Examples 1 to 4 had particle sizes in the range from 100 nm to 500 nm and contained 40~ by weight of monomer mixture and polyisocyanate (1000 , based on the total amount of the respective miniemulsion, and were stable on storage for several weeks.
Table 1 gives an overview of the starting products used for the miniemulsions of Examples 1 to 4, the amounts in which they were used, and the z-average particle diameters of the monomer droplets, which were determined by means of photon correlation spectroscopy in accordance with the principle of dynamic, quasielastic light scattering.
The miniemulsians of Examples 1 to 4 were transferred to suitable steel reactors and heated slowly with stirring at ~rr~m 80 to 90'C. The miniemulsions were stirred at this temperature until the solids content of the resultant primary dispersions 1 to 4 of the invention no longer rose. The primary dispersions of the invention were sedimentation-stoble for several weeks.
Table 1 gives an overview of the polymerization period, the theoretical glass transition temperature Tg, calculated by the method of Fox, of the copolymers present in the primary dispersions of the invention, their hydroxyl number, their molecular weight and their polydispersity of the molecular weight distribution, and also the z-average particle diameters and the solids contents and pH values of the primary dispersions of the invention.

The z-average particle diameters of the miniemulsions 1 to 4 and of the primary dispersions 1 to 4 of the invention were measured using a PCS Malvern Zetasizer 1000.
The primary dispersions of the invention from Examples 1 to 4 were knife coated onto glass plates at a wet film thickness of 150 ~,m and were baked for 30 minutes at 145°C, 160°C and 180°C.
Table 1 gives an overview of imgvrt-ant performance properties of the resultant clearcaats of the invention from Examples 1 to 4.
The results dem~anstrate that the clearcoats of the invention have a high solvent stability, a high gloss, and a smooth surface.

Table l: Mat~al cnn~itivn said grvperties of the a~iai~mul.si.vns 1 to 4 of the ixxventivn, pv.ly~izatian cvaditious, x~aterial cvmpasitivn card gragErt3es of the primary dispsrsioxrs 1 to 4 of the invention, and iacptrrt~.t gerf-vas properties of the cle~va~ts 1 to 4 of the ~:av~eativn Example 1 2 3 4 Miniemulsion:
Composition (parts by weight):

Emulsifiera~ 0.521 0.521 0.521 0.521 Methyl methacrylate 16.95 16.95 16.95 16.95 n-Butyl methacrylate 13.69 13.69 13.69 13.69 Styrene 15.32 14.99 14.34 13.04 Hydroxygrogyl methacrylate 18.25 18.25 18.25 18.25 Diphenylethylene 0.978 1.3 1.955 3.264 Blocked polyisocyanateb~ 34.29 34.29 34.29 34.29 OH:NCO ratio 1:1 1:1 1:1 1:1 Particle diametEr (nm) 151 144 153 151 Polymerization:
Initiatar'~ (parts by weight per 100 parts by weight of emulsifier, monomer mixture and blocked polyisoapanate) 3.26 3.26 3.26 3.26 Polymerization time (h) 10.5 7.0 17.5 11.0 Prima die ersian:

Solids contenta~ (% by weight) 37.9 36.2 35.7 34.7 Particle diameter (nm) 143 154 154 153 pH 6.0 6.0 6.0 6.0 Sediment wet (g) 0 0 0 0 Copolymer:

Number-average molecular weight Mne~ (daltvns) 19.300 14.880 11.550 8.787 Mass-average molecular weight Mw~ (daltons) 110.600 80.490 59.150 44.660 Polydispersity Mw/Mn 5.73 5.41 5.18 5.08 Glass trairsitivn t-emperature (theoretical according to Fox) 74.55 74.55 74.55 74.55 (C) Hydroxyl number (mg KtJH/g) 109 109 109 109 Clearcoat:

MEK-DRf~ (145/160/180C) 3/190/ 5/45/ 3/90/ 1/74/

>200 >200 >200 >200 Gloss (visual) high high high high Surface tExture9~ (visual) 2 1 1 1 a) Sodium lauryl sulfate, Texapvn~ from Henkel;
b) Dimethylgyraznle-blocked commercial polyisocyanate;
c) tent-Hutyl peraxyethylhexanoate;
d) 130°C, one hour;
e) Measured by gel permeation chromatography using polystyrene as internal standard;
f ) Number of double rubs with a cotton pad soaked with methyl ethyl ketone;
l0 g) Rating: 1 = good, 2 - satisfactory, 3 - poor;
Exax~p 1 es 5 and 6 The gragax~~a of pri-ar~ry disps~siu~ of the irweativn and production of cl.ea~t.-s of the iav~errtivn by the prvcss-e of the i~v~tiva For carrying out Examples 5 and 6, the process of Example 2 was repeated but using the water-soluble initiator ammonium gerox~odisulfate instead of the oil-soluble initiator tert-butyl peroxyethylhexanoate.
Additionally, in Example 5, the miniemulsion and the 24~ strength aqueous ammonium peraxadisulfate solution ~~ were metered in as two separate feed streams simultaneously over a period of two hours.
Additionally, in Example 6, the miniemulsion was introduced as initial charge at 80°C and stirred, and the 24~ strength ammonium percrxvdisulfate solution was added dropwise at a uniform rate over the course of two hours. The miniemulsions 5 and 6 contained 35~ by weight of manor mixture and polyisocyanate (1000 , based on the total amount of the respective miniemulsion, and were stable on storage for several weeks.
Table 2 gives an vve-rview of the starting products and their amounts and also the results of the experiments.

' - 53 -Table 2: Mst~ial c mgQS-.f_tivn and grope~rtie-s of the m~niemulsioas 5 and 6 of the invention, golpmer'-.~sation cox~itioas, material compwsvtion and grvpsrti s of the gri~ary di spers-iaas 5 aid 6 of the irnrentivn, and ia~oztant ge~funaranc~e grvgerties of the clea~a<tts 5 and 6 of the invention 8xasapl a 5 6 Miniemulsion:
Composition (parts by weight):

Emulsifiera~ 0.2 0.2 Methyl methacrylate 17.0 17.0 n-Butyl msthacrylate 13.73 13.73 Styrene 15.04 15.04 Hydroxyprvpyl methacrylate 18.31 18.31 Diphenylethylene 1.31 1.31 Blocked polyisocyanateb~ 34.4 34.4 OH:NCO ratio 1:1 1:1 Particle diameter (nm) 210 210 Polymerization:
Initiator' (parts by weight pEr 100 parts by weight of emulsifier, monomer mixture and blocked polyisocyanate) 1.96 1.96 Polymerization time (h) 4.0 3.0 Prima die ersion:

Solids contentd~ (% by weight) 32.7 34.4 Particle diameter (nm) 273 314 pH 3.6 3.1 Copolymer:

Number-average molecular weight Mne~ 11.740 12.020 (daltons) Mass-average molecular weight Mwe~ (daltons)19.830 20.660 Polydispersity Mw/Mn 1.69 1.72 Glass transition tecaperature (theoretical aouvrding to Fox) (C) 74.55 74.55 Hydroxyl number (mg KOH/g) 109 109 Clearcoat:

MEK-DRf~ (145/160/180C) 78/200/ 81/200/

>200 >200 Surface texture9~ (visual)' 2 2 a) Sodium lauryl sulfate, Texagan~ from Henkel;
b) Dimethylpyrazole-blocked commercial polyisocyanate;
c) 100 strength ammonium peraxodisulfate;
d) 130°C, one hour;
e) Measured by gel permeation chromatography using polystyrene as internal standard;
f ) Number of double rubs with a cotton pad soaked with methyl ethyl ketone;
g) Rating: 1 = good, 2 = satisfactory, 3 - poor;
The results demonstrate the particularly high solvent resistance of the clearcoats 5 and 6 of the invention.

Claims (17)

Claims

1. Aqueous primary dispersions and coating materials comprising dispersed and/or emulsified, solid and/or liquid polymer particles and/or dispersed solid core-shell particles having a diameter <= 500 nm, preparable by controlled free-radical microemulsion or miniemulsion polymerization of A) at least one olefinically unsaturated monomer and B) at least one olefinically unsaturated monomer which is different than the olefinically unsaturated monomer (A) and has the general formula I
R1R2C=CR3R4 (I) in which the radicals R1, R2, R3 and R4 each independently of one another are hydrogen atoms or substituted or unsubstituted alkyl, cycloalkyl, alkylcycloalkyl, cycloalkylalkyl, aryl, alkylaryl, cycloalkylaryl arylalkyl or arylcycloalkyl radicals, with the proviso that at least two of the variables R1, R2, R3 and R4 are substituted or unsubstituted aryl, arylalkyl or arylcycloalkyl radicals, especially substituted or unsubstituted aryl radicals;
in the presence of at least C) at least one hydrophobic crosslinking agent for the copolymer resulting from the starting products (A) and (B).

2. A process for preparing aqueous primary dispersions and coating materials comprising dispersed and/or emulsified, solid and/or liquid polymer particles and/or dispersed solid core-shell particles having a diameter <= 500 nm by controlled free-radical microemulsion or miniemulsion polymerization of A) at least one olefinically unsaturated monomer and B) at least one olefinically unsaturated monomer which is different than the olefinically unsaturated monomer (A) and has the general formula I
R1R2C-CR3R4 (I) in which the radicals R1, R2, R3 and R4 each independently of one another are hydrogen atoms or substituted or unsubstituted alkyl, cycloalkyl, alkylcycloalkyl, cycloalkylalkyl, aryl, alkylaryl, cycloalkylaryl arylalkyl or arylcycloalkyl radicals, with the proviso that at least two of the variables R1, R2, R3 and R4 are substituted or unsubstituted aryl, arylalkyl or arylcycloalkyl radicals, especially substituted or unsubstituted aryl radicals;
in the presence of at least C) at least one hydrophobic crosslinking agent for the copolymer resulting from the starting products (A) and (B).

3. The aqueous primary dispersions and coating materials of claim 1 and the process of claim 2, characterized in that the aryl radicals R1, R2, R3 and/or R4 of the compound (B) are phenyl or naphthyl radicals, especially phenyl radicals.

4. The aqueous primary dispersions and coating materials of claim 1 or 3 and the process of claim 2 or 3, characterized in that the substituents in the radicals R1, R2, R3 and/or R4 of the compound (B) are electron-withdrawing or electron-donating atoms or organic radicals, especially halogen atoms, nitrile, nitro, partially or fully halogenated alkyl, cycloalkyl, alkylcycloalkyl, cycloalkylalkyl, aryl, alkylaryl, cycloalkylaryl arylalkyl and arylcycloalkyl radicals; aryloxy, alkyloxy and cycloalkyloxy radicals;
arylthio, alkylthio and cycloalkylthio radicals and/or primary, secondary and/or tertiary amiono groups.

5. The aqueous primary dispersions and coating materials of one of claims 1, 3 or 4 and the process of one of claims 2 to 4, characterized in that blocked polyisocyanates, tris(alkoxycarbonylamino)triazines and/or fully etherified amino resins are used as crosslinking agents (C).

6. The aqueous primary dispersions and coating materials of one of claims 1 or 3 to 5 and the process of one of claims 2 to 5, characterized in that the monomers (A) and (B) are copolymerized in the presence of at least one further hydrophobic compound (D) other than the crosslinking agent (C).

7. The aqueous primary dispersions and coating materials and the process of claim 6, characterized in that the hydrophobic compounds (D) are water-insoluble polymers, oligomers or substances of low molecular mass.

8. The aqueous primary dispersions and coating materials and the process of claim 7, characterized in that esters of alpha, beta-monoolefinically unsaturated carboxylic acids having 3 to 6 carbon atoms with alcohols having 12 to 30 carbon atoms in the alkyl radical; esters of vinyl alcohol and/or allyl alcohol with alkanemonocarboxylic, -sulfonic and/or -phosphonic acids having 12 to 30 carbon atoms in the molecule;
amides of alpha, beta-monoolefinically unsaturated carboxylic acids having 3 to 6 carbon atoms with alkylamines having 12 to 30 carbon atoms in the alkyl radical; macromonomers based on olefinically unsaturated compounds having on average at least one olefinically unsaturated group, in particular at least one terminal olefinically unsaturated group, in the molecule; polysiloxane macromonomers having on average at least one olefinically unsaturated group, in particular at least one terminal olefinically unsaturated group, in the molecule; oligomeric and/or polymeric products of addition polymerization, polycondensation and/or polyaddition; water-insoluble molecular weight regulators, especially mercaptans;
aliphatic, cycloaliphatic and/or aromatic halogenated and/or nonhalogenated hydrocarbons; alkanols and/or alkylamines having at least 12 carbon atoms in the alkyl radical; organosilanes and/or organosiloxanes;
vegetable, animal, semisynthetic and/or synthetic oils;
and/or hydrophobic dyes are used as hydrophobic compounds (D).

9. The aqueous primary dispersions and coating materials of one of claims 1 or 3 to 8 and the process of one of claims 2 to 8, characterized in that the monomers (A) and (B) are copolymerized in the presence of emulsifiers and/or protective colloids (E).

10. The aqueous primary dispersions and coating materials of one of claims 1 or 3 to 9 and the process of one of claims 2 to 9, characterized in that as monomers (A) a1) substantially acid-group-free (meth)acrylic esters;
a2) monomers which carry per molecule at least one hydroxyl group and are substantially free from acid groups;
a3) monomers which carry per molecule at least one acid group which can be converted into the corresponding acid anion group;
a4) vinyl esters of alpha-branched monocarboxylic acids having 5 to 18 carbon atoms in the molecule;
a5) reaction products of acrylic acid and/or methacrylic acid with the glycidyl ester of an alpha-branched monocarboxylic acid having from 5 to 18 carbon atoms per molecule;
a6) cyclic and/or acyclic olefins;
a7) (meth)acrylamides;

a8) monomers containing epoxide groups;
a9) vinylaromatic hydrocarbons;
a10) nitriles;
a11) vinyl compounds, especially vinyl halides and/or vinylidene dihalides, N-vinylpyrrolidone, vinyl ethers and/or vinyl esters;
a12) allyl compounds, especially allyl ethers and allyl esters;
a13) polysiloxane macromonomers having a number-average molecular weight Mn of from 1000 to 40,000 and containing on average from 0.5 to 2.5 ethylenically unsaturated double bonds per molecule; and/or a14) acryloyloxysilane-containing vinyl monomers, preparable by reacting hydroxy-functional silanes with epichlorohydrin and then reacting the reaction product with methacrylic acid and/or hydroxyalkyl esters of (meth)acrylic acid;
are used, with the proviso that the monomers (a3) are not used as the sole monomers (A).

11. The aqueous primary dispersions and coating materials and the process of claim 10, characterized in that at least one monomer (A) containing reactive functional groups which are able to undergo crosslinking reactions with the complementary reactive functional groups of the crosslinking agents (C) is used.

12. The aqueous primary dispersions and coating materials of one of claims 1 or 3 to 11 and the process of one of claims 2 to 11, characterized in that the controlled free-radical microemulsion or miniemulsion polymerization is initiated by water-soluble and/or oil-soluble initiators which form free radicals.

13. The aqueous primary dispersions and coating materials of one of claims 1 or 3 to 12 and the process of one of claims 2 to 12, characterized in that the dispersed particles are core-shell particles with cores of organic solids and with shells of polymers which contain in copolymerized form at least one monomer (A) and at least one monomer (B).

14. The aqueous primary dispersions and coating materials of one of claims 1 or 3 to 13 and the process of one of claims 2 to 13, characterized in that the cores of the core-shell particles are prepared by free-radical, especially controlled free-radical, microemulsion or miniemulsion polymerization.

15. The aqueous primary dispersions and coating materials of one of claims 1 or 3 to 14, characterized in that they comprise at least one coatings additive (F).

16. The aqueous primary dispersions and coating materials of one of claims 1 or 3 to 15, characterized in that they comprise constituents which can be cured with actinic radiation.
17. Use of the aqueous primary dispersions and coating materials of one of claims 1 or 3 to 16 or of the aqueous primary dispersions and coating materials prepared by the process of one of claims 2 to 13 in automotive OEM finishing and refinishing, industrial coating, including coil coating, container coating and the coating of electrical components, and furniture coating.

17. Primed or unprimed substrates comprising at least one single-coat or multicoat clearcoat system and/or at least one single-coat or multicoat color and/or effect paint system based on the aqueous primary dispersions and coating materials of one of claims 1 or 3 to 16 or on the aqueous primary dispersions and coating materials prepared by the process of one of claims 2 to 14.