HK1149035A - Emulsion polymers, aqueous dispersions and method for producing the same - Google Patents

Description

Emulsion polymers, aqueous dispersions and methods for their preparation

Technical Field

The present invention relates to emulsion polymers and aqueous dispersions comprising these emulsion polymers. The invention further relates to a process for the preparation of these dispersion and emulsion polymers.

Background

Coatings, in particular paints, have long been prepared synthetically. Many of these coatings are based on so-called alkyd resins, which are prepared using polybasic acids, alcohols and fatty acids and/or fatty acid derivatives. One particular class of these alkyds forms crosslinked films when exposed to oxygen, wherein the crosslinking is carried out by oxidation in the presence of unsaturated groups. Many of these alkyd resins contain organic solvents or dispersants so that the resin can be applied to the coated body in a thin layer. However, the use of these solvents should be abandoned for reasons of environmental protection and working safety. Corresponding resins based on aqueous dispersions have therefore been developed, but their storage stability is limited. In addition, many alkyd resins have too high a water absorption, or too low a solvent resistance and hardness. Therefore, attempts have been made to modify or replace the conventional alkyd-based paints described above.

For example, US 4,010,126 discloses compositions comprising an alkyd resin modified with a (meth) acrylate polymer and subsequently used in emulsion polymerization. The composition is prepared via multiple steps, making the resin very expensive and complex to prepare.

Paint compositions based on solution polymers based on vinyl monomers are described, for example, in DE-A-10106561. However, the composition comprises a high proportion of organic solvent.

Furthermore, aqueous dispersions based on (meth) acrylate polymers are also known. For example, the publication DE-A-4105134 describes aqueous dispersions which can be used as binders in paints. However, the preparation of these binders is carried out via a plurality of stages, wherein first a solution polymer is prepared, which after neutralization is used for the emulsion polymerization.

Furthermore, DE-A-2513516 describes aqueous dispersions comprising polymers based on (meth) acrylates, a portion of which contain unsaturated alcohol residues. The disadvantage of said dispersions is in particular their expensive and complicated preparation, in which the (meth) acrylate-based polymers are obtained by solution polymerization. The polymers here have a high proportion of acid groups, said proportion being 5 to 20% by weight, based on the solution polymer.

The publication DE-A-2638544 describes oxidatively drying aqueous dispersions comprising emulsion polymers based on (meth) acrylates, some of which have unsaturated alcohol residues. However, chain transfer agents have been used to prepare emulsion polymers such that the emulsion polymers exhibit high solubility.

In addition, aqueous dispersions comprising oxidatively drying Polymers are described in detail in F. -B.Chen, G.Bufkin, "Crosslinkable emulsions Polymers by autoxidation II", Journal of Applied Polymer Science, Vol.30, 4551-. The polymer contains from 2 wt% to 8 wt% units derived from a (meth) acrylate ester having an unsaturated, long chain alcohol residue. However, these polymers do not contain any units obtained by polymerization of monomers containing acid groups. For many applications, the shelf life of these dispersions and the hardness of the coating are insufficient.

Furthermore, publication US 5,750,751 describes polymers based on vinyl monomers which are capable of crosslinking at room temperature. The polymers may be obtained both by solution polymerization and by emulsion polymerization. The monomer mixture to be polymerized may contain, inter alia, (meth) acrylates whose alcohol residues have been modified by unsaturated fatty acids. The polymer obtained by solution polymerization and emulsion polymerization of the modified (meth) acrylate exhibits high solubility due to the use of a chain transfer agent. However, a disadvantage of the coating described in US 5,750,751 is that plasticizing solvents must be added, which should be avoided on the basis of environmental protection considerations.

An improvement in this respect is achieved viｃA the teaching of publication EP- ｃA-1044993. This document describes aqueous dispersions based on (meth) acrylates. The mixture to be polymerized comprises (meth) acrylates which have been modified by unsaturated fatty acids. A key aspect of this solution is the use of polymers having a particularly broad molecular weight distribution, with a number average of the molecular weight in the range of 300-3000 g/mol. However, a disadvantage of this system is that the resulting film is too soft for many applications.

Furthermore, document WO 2006/013061 describes dispersions comprising particles based on (meth) acrylates. The monomer mixture used to prepare such particles comprises a (meth) acrylate that has been modified by an unsaturated fatty acid. However, in the examples, the monomers containing acid groups were not polymerized. In addition, the proportion of (meth) acrylate modified with unsaturated fatty acids is very high. The disadvantages of the dispersions described in WO 2006/013061 are, in particular, their complicated preparation and the high proportion of residual monomers. The minimum proportion of soluble emulsion polymer is not described in this publication.

In addition, dispersions which can contain alkyd resins in addition to (meth) acrylate-based polymers are also known from the prior art. For example, document WO 98/22545 describes polymers having units derived from (meth) acrylates containing unsaturated alcohol residues. These polymers may be used in conjunction with an alkyd resin. However, solvents are used in order to prepare the lacquer from the polymer. Aqueous dispersions are not described in WO 98/22545. These compositions therefore have the disadvantages described above.

In addition, Japanese publication JP 59011376 describes (meth) acrylate-based emulsion polymers. Such a dispersion has a dynamic viscosity of at least 200mPas for a solids content of about 40%. Particle size is not mentioned in this publication. However, due to the high viscosity of the dispersion, the emulsion polymer can be considered to have a particle size below 40 nm. A disadvantage of the dispersions described in this publication is their low storage capacity.

Disclosure of Invention

In view of the prior art, it was therefore an object of the present invention to provide emulsion polymers which can be processed to give coatings and coatings having outstanding properties. In particular, such dispersion or emulsion polymers should have a very low residual monomer content. It is therefore a further object of the present invention to provide dispersions having particularly long storage capacities and shelf lives. In addition, the hardness of the coatings obtainable from coatings with such emulsion polymers should be able to be varied within wide limits. In particular, it should be possible to obtain particularly hard, scratch-resistant coatings. Another object may be considered to be to provide emulsion polymers which can be used to obtain coatings in the absence of volatile organic solvents. Coatings obtainable from such aqueous dispersions should have high weathering resistance, in particular high UV stability. In addition, films obtainable from such aqueous dispersions should have a low viscosity after a short time.

These objects, and others which are not explicitly mentioned but which can be easily deduced or inferred from the context of the introductory discussion herein, are achieved by emulsion polymers having all the features of claim 1. Suitable modifications of the emulsion polymers according to the invention are claimed in the dependent claims.

The present invention therefore provides emulsion polymers comprising at least one (meth) acrylate segment comprising

From 1% by weight to 30% by weight of units derived from (meth) acrylates having at least one double bond in the alkyl radical and from 8 to 40 carbon atoms,

from 0.1% to 10% by weight of units derived from acid group-containing monomers, and

from 50% by weight to 98.9% by weight of units derived from (meth) acrylates having from 1 to 6 carbon atoms in the alkyl radical,

in each case based on (meth) acrylate segments,

characterized in that the emulsion polymer has a particle radius of at least 50 nm.

Via the measures according to the invention, advantages can also be obtained, among others, including the following:

the dispersions and emulsion polymers of the present invention have a very low residual monomer content.

The hardness of the coatings obtainable from the emulsion polymer-containing dispersions of the invention can vary within wide limits. In a preferred development, particularly hard scratch-resistant coatings can be obtained according to the invention. The coatings obtainable from the dispersion and emulsion polymers of the invention exhibit surprisingly high solvent resistance, which is demonstrated in particular in tests with methyl isobutyl ketone (MIBK) or ethanol. For example, the coatings obtained show excellent grading, in particular in experiments according to DIN 68861-1 furniture test. In this case, the coating can be cleaned even with nonpolar solvents, in particular with washing gasoline, without the coating being irreversibly damaged thereby.

The coatings obtainable using the emulsion polymers of the present invention generally require volatile organic solvents. In addition, the dispersions of the invention exhibit high storage stability, long shelf life and very good storage capacity. In particular, aggregates are hardly formed.

The coatings obtainable from such aqueous dispersions exhibit high weathering resistance, in particular high UV stability. In addition, films obtainable from such aqueous dispersions have a low viscosity after a short time. In addition, the coatings of the present invention exhibit high wet film stand-up stability (Standfestigkeit) and increased open time.

Furthermore, the coatings obtainable from the dispersions of the invention exhibit particularly high adhesive strength, abrasion resistance and load-bearing capacity on many substrates. In particular, the preferred coatings, and substrates coated with the coatings of the present invention, can be exposed to high mechanical loads without crack formation of the coating occurring.

The dispersion and emulsion polymers of the present invention can be prepared inexpensively on a large scale. The dispersion and emulsion polymers of the present invention are environmentally friendly and can be safely processed and prepared without significant cost and complexity. The dispersions of the invention here exhibit very high shear stability.

The emulsion polymers of the present invention comprise at least one (meth) acrylate segment. The expression "emulsion polymer" here denotes a macromolecular compound which can be obtained by emulsion polymerization. The term "segment" means that the emulsion polymer comprises at least one segment having (meth) acrylate repeating units. The emulsion polymer can be composed of one segment thus constructed or can have further segments. The emulsion polymer can preferably be obtained by means of free-radical polymerization.

The weight proportion of the units is thus derived from the weight proportion of the corresponding monomers used to prepare such polymers. The weight proportion of (meth) acrylate segments is preferably at least 10% by weight, more preferably at least 20% by weight, based on the weight of the emulsion polymer. The emulsion polymer preferably comprises at least 40% by weight, more preferably at least 60% by weight, very particularly preferably at least 90% by weight, of (meth) acrylate.

The (meth) acrylate segment comprises from 1 to 30% by weight, preferably from 5% to 25% by weight, more preferably from 10% to 20% by weight, of units derived from a (meth) acrylate containing at least one double bond in the alkyl group and from 8 to 40 carbon atoms, based on the total weight of such (meth) acrylate segment.

The expression "(meth) acrylate" covers both methacrylates and acrylates and also mixtures of the two. (meth) acrylic acid esters containing at least one double bond and 8 to 40 carbon atoms in the alkyl group are esters of (meth) acrylic acid whose alcohol residue has at least one double bond and 8 to 40 carbon atoms. The alkyl or alcohol residue may preferably contain 10 to 30, more preferably 12 to 20 carbon atoms, wherein such groups may include heteroatoms, especially oxygen, nitrogen or sulfur atoms. The alcohol residue may have one, two, three or more double bonds. The polymerization conditions in the preparation of the emulsion polymers are preferably selected such that as large a proportion as possible of the double bonds of the alcohol residues remain during the polymerization. This can be achieved, for example, by steric hindrance of the double bond present in the alcohol residue.

The iodine number of the (meth) acrylates containing at least one double bond in the alkyl radical and from 8 to 40 carbon atoms used for preparing the emulsion polymers is preferably at least 40, more preferably at least 80, very preferably at least 140g of iodine per 100g of (meth) acrylate.

Such (meth) acrylates generally correspond to the general formula (I)

(1)，

Wherein the radical R represents hydrogen or methyl, R¹Represents a linear or branched group containing 8 to 40 carbon atoms containing at least one double bond.

(meth) acrylic esters containing at least one double bond and 8 to 40 carbon atoms in the alkyl radical can be obtained, for example, by esterification of (meth) acrylic acid with alcohols containing at least one double bond and 8 to 40 carbon atoms, reaction of (meth) acrylic acid halides with the alcohols or transesterification of (meth) acrylic esters with the alcohols. These reactions are described, for example, in Ullmann's Encyclopedia of Industrial Chemistry, 5 th edition on CD-ROM, or F. -B.Chen, G.Bufkin, "Crosslinkable emulsions Polymers by Autooxidation I", Journal of Applied Polymer Science, Vol.30, 4571-4582 (1985).

Alcohols suitable for this purpose include, in particular, octenol, nonenol, decenol, undecenol, dodecenol, tridecenol, tetradecenol, pentadecenol, hexadecenol, heptadecenol, octadecenol, nonadecenol, eicosenol, docosenol, octadienol, nonadienol, decadienol, undecenol, dodecadienol, tridecadiene-ol, tetradecadiene-ol, pentadecedienol, hexadecadiene-ol, heptadecadienol, octadecadienol, nonadecadienol, eicosadiene-ol and/or docosedienol. These so-called fatty alcohols are in some cases commercially available or can be obtained from fatty acids, wherein the reaction is described, for example, in F. -B.Chen, G.Bufkin, Journal of Applied Polymer Science, Vol.30, 4571-4582 (1985).

Preferred (meth) acrylates obtainable by the present process include, inter alia, octadecenylene (meth) acrylate, octadecatrienyl (meth) acrylate, hexadecenyl (meth) acrylate, octadecenyl (meth) acrylate and hexadecadienyl (meth) acrylate.

In addition, (meth) acrylates having at least one double bond and 8 to 40 carbon atoms in the alkyl radical can also be obtained by reacting unsaturated fatty acids with (meth) acrylates having reactive groups in the alcohol residue. The reactive groups include, inter alia, hydroxyl groups as well as epoxy groups. Thus, for example, hydroxyalkyl (meth) acrylates such as 3-hydroxypropyl (meth) acrylate, 3, 4-dihydroxybutyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2, 5-dimethyl-1, 6-hexanediol (meth) acrylate, 1, 10-decanediol (meth) acrylate; or an epoxy group-containing (meth) acrylate, an example being glycidyl (meth) acrylate, as a reactant for preparing the above-mentioned (meth) acrylate.

Fatty acids suitable for the above (meth) acrylate reaction are in many cases commercially available and obtained from natural sources. They include, in particular, undecylenic acid, palmitoleic acid, oleic acid, elaidic acid, vaccenic acid, eicosenoic acid, cetoleic acid, erucic acid, nervonic acid, linoleic acid, linolenic acid, arachidonic acid, eicosapentaenoic acid, 4, 7, 11-docosatriene-18-ynoic acid and/or docosahexaenoic acid (b)。

Preferred (meth) acrylates obtainable by the present process include, inter alia, (meth) acryloyloxy-2-hydroxypropyl-linoleate, (meth) acryloyloxy-2-hydroxypropyl-linolenate and (meth) acryloyloxy-2-hydroxypropyl-oleate.

The reaction of unsaturated fatty acids with (meth) acrylates containing reactive groups in the alcohol residue is known per se and is described, for example, in DE-A-4105134, DE-A-2513516, DE-A-2638544 and U.S. Pat. No. 3, 5,750,751.

The above-mentioned (meth) acrylates containing at least one double bond may be used singly or as a mixture of two or more (meth) acrylates.

In particular (meth) acrylate segments comprising a high proportion of units derived from (meth) acryloyloxy-2-hydroxypropyl-linoleate show surprising advantages. In particular, a comparatively scratch-resistant, solvent-resistant coating can be obtained, wherein the coating can be processed particularly easily and has surprisingly high storage stability.

These advantages can be achieved in particular with (meth) acrylate segments comprising at least 20% by weight, preferably at least 40% by weight, very preferably at least 50% by weight, of units derived from (meth) acryloyloxy-2-hydroxypropyl-linoleate, based on the weight of units derived from (meth) acrylates having at least one double bond and from 8 to 40 carbon atoms in the alkyl group. Preferably, the (meth) acrylate segment contains from 45 wt% to 80 wt%, more preferably from 55 wt% to 70 wt% of units derived from (meth) acryloyloxy-2-hydroxypropyl-linoleate, based on the weight of units derived from a (meth) acrylate ester containing at least one double bond and from 8 to 40 carbon atoms in the alkyl group.

According to another aspect of the present invention, it is preferred that the (meth) acrylate segment comprising at least 5 wt%, preferably at least 10 wt%, more preferably at least 15 wt% of units derived from (meth) acryloyloxy-2-hydroxypropyl-oleate is based on the weight of units derived from a (meth) acrylate ester having at least one double bond and 8 to 40 carbon atoms in the alkyl group. Preferably, the polymer contains from 15 wt% to 45 wt%, more preferably from 20 wt% to 35 wt% of units derived from (meth) acryloyloxy-2-hydroxypropyl-oleate, based on the weight of units derived from a (meth) acrylate ester containing at least one double bond and from 8 to 40 carbon atoms in the alkyl group.

In addition, a particular improvement can be achieved by the weight ratio of units derived from (meth) acryloyloxy-2-hydroxypropyl-linoleate to units derived from (meth) acryloyloxy-2-hydroxypropyl-oleate being greater than or equal to 1, wherein such weight ratio is more preferably in the range from 8: 1 to 1: 1, particularly preferably from 5: 1 to 3: 2.

In addition, the (meth) acrylate segments of the emulsion polymers of the present invention comprise from 0.1% to 10% by weight, preferably from 0.5% to 8% by weight, more preferably from 1% to 5% by weight, of units derived from acid group-containing monomers, based on the total weight of the (meth) acrylate segments.

The acid group-containing monomer is a compound which can be preferably subjected to radical copolymerization with the above-mentioned (meth) acrylate. They include, for example, sulfonic acid group-containing monomers such as vinylsulfonic acid; phosphonic acid group-containing monomers, such as vinylphosphonic acid; and unsaturated carboxylic acids such as methacrylic acid, acrylic acid, fumaric acid, and maleic acid. Methacrylic acid and acrylic acid are particularly preferred. The acid group-containing monomers may be used alone or as a mixture of two, three or more acid group-containing monomers.

The (meth) acrylate segments of the emulsion polymers of the present invention also comprise from 50% to 98.9% by weight, preferably from 60% to 95% by weight, more preferably from 70 to 90% by weight, based on the total weight of the (meth) acrylate segments, of units derived from a (meth) acrylate having from 1 to 6 carbon atoms in the alkyl group.

Such (meth) acrylates generally correspond to the following general formula (II)

(11)，

Wherein the radical R represents hydrogen or methyl, R²Denotes straight-chain or branched radicals having from 1 to 6 carbon atoms, preferably from 1 to 4 carbon atoms.

They include, in particular, (meth) acrylates derived from saturated alcohols, such as methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, tert-butyl (meth) acrylate and pentyl (meth) acrylate, hexyl (meth) acrylate; cycloalkyl (meth) acrylates such as cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate; and (meth) acrylic esters derived from unsaturated alcohols, such as 2-propynyl (meth) acrylate, allyl (meth) acrylate, and vinyl (meth) acrylate.

It is particularly preferred to use mixtures comprising methacrylates and acrylates. Thus, mixtures of methyl methacrylate and acrylates containing 2 to 6 carbons, such as ethyl acrylate, butyl acrylate and hexyl acrylate, among others, may be used.

In addition to the units mentioned above, the (meth) acrylate segments of the emulsion polymers of the invention may also have units derived from comonomers. These comonomers are different from the units of the emulsion polymer described above, but can be copolymerized with the monomers described above.

These include, for example, (meth) acrylic esters having at least 7 carbon atoms in the alkyl group and derived from saturated alcohols, such as 2-ethylhexyl (meth) acrylate, heptyl (meth) acrylate, 2-tert-butyl heptyl (meth) acrylate, octyl (meth) acrylate, 3-isopropyl heptyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, undecyl (meth) acrylate, 5-methylundecyl (meth) acrylate, dodecyl (meth) acrylate, 2-methyldodecyl (meth) acrylate, tridecyl (meth) acrylate, 5-methyltrodecyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, fatty acid esters such as fatty acid esters, fatty acid esters such as fatty acid, Cetyl (meth) acrylate, 2-methylhexadecyl (meth) acrylate, heptadecyl (meth) acrylate, 5-isopropylheptadecyl (meth) acrylate, 4-tert-butyloctadecyl (meth) acrylate, 5-ethyloctadecyl (meth) acrylate, 3-isopropyloctadecyl (meth) acrylate, octadecyl (meth) acrylate, nonadecyl (meth) acrylate, eicosyl (meth) acrylate, cetyleicosyl (meth) acrylate, stearyleicosyl (meth) acrylate, docosyl (meth) acrylate, and/or eicosyltridecyl (meth) acrylate; cycloalkyl (meth) acrylates such as 3-vinylcyclohexyl (meth) acrylate, bornyl (meth) acrylate, cycloalkyl (meth) acrylates such as 2, 4, 5-tri-tert-butyl-3-vinylcyclohexyl (meth) acrylate, 2, 3, 4, 5-tetra-tert-butylcyclohexyl (meth) acrylate; nitriles of (meth) acrylic acid and other nitrogen-containing methacrylates, such as N- (methacryloyloxyethyl) diisobutyl ketimine, N- (methacryloyloxyethyl) dihexadecyl ketimine, methacrylamidoacetonitrile, 2-methacryloyloxyethyl methyl cyanamide, cyanomethyl methacrylate; aryl (meth) acrylates, for example benzyl (meth) acrylate or phenyl (meth) acrylate, where the aryl radicals may each be unsubstituted or substituted up to four times; (meth) acrylates containing two or more (meth) acryloyl groups, glycol di (meth) acrylates such as ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetra-and polyethylene glycol di (meth) acrylate, 1, 3-butanediol (meth) acrylate, 1, 4-butanediol (meth) acrylate, 1, 6-hexanediol di (meth) acrylate, glycerol di (meth) acrylate; ethoxylated bisphenol a dimethacrylate; (meth) acrylates having three or more double bonds, such as glycerol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate and dipentaerythritol penta (meth) acrylate;

vinyl halides such as vinyl chloride, vinyl fluoride, vinylidene chloride and vinylidene fluoride; heterocyclic (meth) acrylates such as 2- (1-imidazolyl) ethyl (meth) acrylate, 2- (4-morpholinyl) ethyl (meth) acrylate and 1- (2-methacryloyloxyethyl) -2-pyrrolidone;

vinyl esters, such as vinyl acetate;

styrene, substituted styrenes having an alkyl substituent in the side chain, such as α -methylstyrene and β -ethylstyrene, substituted styrenes having an alkyl substituent in the ring, such as vinyltoluene and p-methylstyrene, and halogenated styrenes, such as monochlorostyrene, dichlorostyrene, tribromostyrene and tetrabromostyrene;

heterocyclic vinyl compounds, for example 2-vinylpyridine, 3-vinylpyridine, 2-methyl-5-vinylpyridine, 3-ethyl-4-vinylpyridine, 2, 3-dimethyl-5-vinylpyridine, vinylpyrimidine, vinylpiperidine, 9-vinylcarbazole, 3-vinylcarbazole, 4-vinylcarbazole, 1-vinylimidazole, 2-methyl-1-vinylimidazole, N-vinylpyrrolidone, 2-vinylpyrrolidone, N-vinylpyrrolidine, 3-vinylpyrrolidine, N-vinylcaprolactam, N-vinylbutyrolactam, vinyloxolane, vinylfuran, vinylthiophene, vinylthiacyclopentane, vinylmethyloxacyclopentane, vinylmethyloxa, Vinyl and hydrogenated vinyl thiazoles, vinyl oxazoles and hydrogenated vinyl oxazoles;

vinyl ethers and isoprenyl ethers;

maleic acid derivatives, for example maleic anhydride, esters of maleic acid, for example dimethyl maleate, methylmaleic anhydride, maleimide, methylmaleimide; and fumaric acid derivatives such as dimethyl fumarate.

The proportion of units derived from the comonomer can vary depending on the intended use and property profile of the polymer. In general, such a proportion may be in the range of 0 wt% to 45 wt%, preferably 2 wt% to 30 wt%, more preferably 3 wt% to 10 wt%, based on the total weight of the (meth) acrylate segment.

The weathering resistance of the coatings can be improved in particular by reducing the proportion of styrene monomer in the coating or emulsion polymer, so that coatings which are particularly UV-resistant can be obtained with styrene-free coatings. According to a particular development of the invention, the emulsion polymer comprising at least one (meth) acrylate segment preferably contains up to 30% by weight, more preferably up to 15% by weight, of units derived from styrene, substituted styrene having alkyl substituents in the side chains, substituted styrene having alkyl substituents in the ring and/or halogenated styrene, based on the total weight of the (meth) acrylate segment.

Coatings which are particularly scratch-and solvent-resistant can be obtained in particular by: the emulsion polymer comprising at least one (meth) acrylate segment comprises up to 10% by weight of units derived from (meth) acrylates obtainable by reacting saturated fatty acids with at least one (meth) acrylate containing reactive groups in the alcohol residue, based on the total weight of the (meth) acrylate segment. These coatings, in particular comprising emulsion polymers, which preferably comprise from 0.05% to 5% by weight, more preferably from 0.1 to 3% by weight, of units derived from (meth) acrylates obtainable by reacting saturated fatty acids with at least one (meth) acrylate containing reactive groups in the alcohol residue, based on the total weight of the (meth) acrylate segments, show surprising improvements. As the (meth) acrylate containing a reactive group in the alcohol residue, glycidyl (meth) acrylate can be preferably used. The saturated fatty acids which can be reacted with the (meth) acrylates containing at least one reactive group in the alcohol residue, preferably glycidyl (meth) acrylate, preferably contain from 10 to 26, more preferably from 12 to 22 carbon atoms. Saturated fatty acids having from 10 to 26 carbon atoms include, in particular, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, margaric acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, palmitoleic acid and stearic acid.

Preferably, the emulsion polymer may have a fraction soluble in Tetrahydrofuran (THF) at 20 ℃ of 2 wt% to 60 wt%, more preferably 10 wt% to 50 wt%, and very preferably 20 wt% to 40 wt%, based on the weight of the emulsion polymer. To determine the soluble fraction, a sample of a polymer containing at least one (meth) acrylate segment, which has been dried with exclusion of oxygen, is stored in a 200-fold amount of solvent at 20 ℃ for 4h, based on the weight of the sample. To exclude oxygen, the sample may be dried under nitrogen or under reduced pressure, for example. Subsequently, the solution is separated from the insoluble fraction, for example by filtration. After evaporation of the solvent, the weight of the residue was determined. For example, a sample of 0.5g of the emulsion polymer dried under reduced pressure can be stored in 150ml of THF for 4 hours.

According to a preferred development of the invention, the emulsion polymer can exhibit a degree of swelling in Tetrahydrofuran (THF) at 20 ℃ of at least 1000%, more preferably at least 1400%, very preferably at least 1600%. The upper limit of the degree of swelling is not critical per se, with a degree of swelling of preferably up to 5000%, more preferably up to 3000%, very preferably up to 2500%. To determine the degree of swelling, samples of the emulsion polymer which had been dried with exclusion of oxygen were stored in 200-fold amounts of THF at 20 ℃ for 4 hours. As a result, the sample swelled. The thus swollen sample was separated from the upper solvent. Subsequently, the solvent was removed from the sample. For example, most of the solvent may be evaporated at room temperature (20 ℃). The solvent residue can be removed in a drying oven (140 ℃), wherein it is generally achieved within 1 hour. The swelling degree is obtained from the weight of the solvent absorbed by the sample and the weight of the dried sample. In addition, the soluble fraction of the emulsion polymer was obtained from the difference between the weight of the sample before the swelling experiment and the weight of the dried sample after the swelling experiment.

The particle radius of the emulsion polymer is at least 50 nm. The radius of the particles is preferably in the range of 60nm to 500nm, more preferably 70 to 150nm, and most preferably 75 to 100 nm. The radius of the particles can be determined using PCS (photon correlation spectroscopy), where the data given relate to d₅₀Values (50% smaller, 50% larger of the particles). For this purpose, for example, a Beckman Coulter N5 Submicron Particle Size Analyzer can be used.

The glass transition temperature of the (meth) acrylate segment is preferably in the range of-30 ℃ to 70 ℃, more preferably-20 to 40 ℃, and very preferably 0-25 ℃. The glass transition temperature may be influenced by the nature and proportions of the monomers used to prepare the (meth) acrylate segment. The glass transition temperature Tg of the polymers can be determined in a known manner by means of Differential Scanning Calorimetry (DSC). Further, the glass transition temperature Tg can also be roughly calculated in advance using the Fox equation. According to Fox t.g., fill.am. physics soc.1, 3, page 123 (1956) the following applies:

wherein x_nDenotes the mass fraction (% by weight/100) of the monomer n, Tg_nDenotes the glass transition temperature (in kelvin) of the homopolymer of the monomer n. Other useful information can be obtained from Polymer Handbook, second edition, J.Wiley, to those skilled in the art&Sons, New York (1975), which gives the Tg values of the most common homopolymers.

For many applications and properties, the architecture of the emulsion polymer and/or the (meth) acrylate segments is not critical. The emulsion polymer and/or (meth) acrylate segment may thus be a random copolymer, a gradient copolymer, a block copolymer, and/or a graft copolymer. The block copolymer and/or gradient copolymer may be obtained, for example, by: the monomer composition is changed discontinuously during the chain extension. According to a preferred aspect of the present invention, the emulsion polymer is a random copolymer in which the monomer composition is substantially constant during the polymerization. However, because the monomers may have different copolymerization parameters, the precise composition within the polymer chain of the emulsion polymer and/or the (meth) acrylate segment may fluctuate.

The emulsion polymer may be a homogeneous polymer that forms particles of the same composition, for example, in an aqueous dispersion. In this case, the emulsion polymer may be composed of one or more (meth) acrylate segments comprising from 1% to 30% by weight of units derived from a (meth) acrylate having at least one double bond in the alkyl group and from 8 to 40 carbon atoms, from 0.1% to 10% by weight of units derived from an acid group-containing monomer, and from 50% to 98.9% by weight of units derived from a (meth) acrylate having from 1 to 6 carbon atoms in the alkyl group, based on the weight of the (meth) acrylate segments.

According to another embodiment, the emulsion polymer may be a core-shell polymer, which may have one, two, three or more shells. In this case, the (meth) acrylate segment preferably forms the outermost shell of such core-shell polymers. The shell may be covalently linked to the core or the inner shell. In addition, the shell may be polymerized onto the core or the inner shell. In this embodiment, the (meth) acrylate segment can in many cases be separated and isolated from the core by means of a suitable solvent.

The weight ratio of the (meth) acrylate segment to the core may preferably be in the range of 2: 1 to 1: 6, more preferably 1: 1 to 1: 3.

The core may preferably be formed from a polymer comprising from 50 wt% to 100 wt%, preferably from 60 wt% to 90 wt%, of units derived from a (meth) acrylate ester. Preference is given here to esters of (meth) acrylic acid whose alcohol residue preferably contains from 1 to 30 carbon atoms, more preferably from 1 to 20 carbon atoms, very preferably from 1 to 10 carbon atoms. They include, in particular, (meth) acrylates derived from saturated alcohols, such as methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, tert-butyl (meth) acrylate and pentyl (meth) acrylate, hexyl (meth) acrylate.

According to a particular embodiment of the invention, for the preparation of the core, a mixture comprising methacrylates and acrylates can be used. For example, mixtures of methyl methacrylate and acrylates containing 2 to 6 carbons, such as ethyl acrylate, butyl acrylate and hexyl acrylate, among others, may be used.

In addition, the polymer of the core may comprise the comonomers described above. According to a preferred refinement, the core can be crosslinked. Such crosslinking may be achieved by using monomers containing two, three or more free-radically polymerizable double bonds.

The shell comprising (meth) acrylate segments of the emulsion polymer of the invention may preferably comprise from 15% to 28% by weight of units derived from (meth) acrylates having at least one double bond in the alkyl group and from 8 to 40 carbon atoms.

According to a particular aspect, the core may preferably have a glass transition temperature of-30 to 200 ℃, more preferably-20 to 150 ℃. The shell preferably formed by the (meth) acrylate segments of the emulsion polymer of the invention may preferably have a glass transition temperature of from-30 ℃ to 70 ℃, more preferably from-20 ℃ to 40 ℃, very preferably from 0 ℃ to 25 ℃. According to a particular aspect of the invention, the glass transition temperature of the core may be greater than the glass transition temperature of the shell. Suitably, the glass transition temperature of the core may be at least 10 ℃, preferably at least 20 ℃ above the glass transition temperature of the shell.

The iodine number of the emulsion polymers of the invention, measured in accordance with DIN 53241-1, is preferably from 1 to 150g of iodine per 100g of emulsion polymer, more preferably from 2 to 100g of iodine per 100g of emulsion polymer, very preferably from 5 to 40g of iodine per 100g of emulsion polymer. The iodine value can be measured in particular with the aid of the dispersions of the invention.

Suitably, the emulsion polymer may have an acid number of from 0.1 to 40mg KOH/g, preferably from 1 to 20mg KOH/g, very preferably from 2 to 10mg KOH/g. The acid number can be determined by means of dispersions in accordance with DIN EN ISO 2114.

The hydroxyl number of the emulsion polymer may preferably be in the range from 0 to 200mg KOH/g, more preferably from 1 to 100mg KOH/g, very preferably from 3 to 50mg KOH/g. The hydroxyl number can be determined by means of dispersions according to ASTM E222.

The emulsion polymers of the invention can be obtained by known emulsion polymerization processes which are described in particular in Ullmann's Encyclopedia of Industrial Chemistry, fifth edition. For this purpose, an aqueous phase is generally prepared which, in addition to water, may also comprise the customary additives, in particular emulsifiers and protective colloids for emulsion stabilization.

Monomers are then added to this aqueous phase and polymerized in the aqueous phase. When producing homogeneous polymer particles, the monomer mixture can be added here continuously or in portions over a time interval.

The dispersion of the monomer-containing phase in the aqueous phase can be carried out using known reagents. This includes, inter alia, mechanical methods and the application of ultrasound.

The monomer mixture used to prepare the emulsion polymers of the present invention preferably comprises from 1% to 30% by weight of a (meth) acrylate ester having at least one double bond in the alkyl group and from 8 to 40 carbon atoms, from 0.1% to 10% by weight of a monomer having an acid group, and from 50% to 98.9% by weight of a (meth) acrylate ester having from 1 to 6 carbons in the alkyl group.

The monomer mixture more preferably contains 1% to 5% by weight of acid group-containing monomers.

In the preparation of homogeneous emulsion polymers, preference is given to using monomer mixtures which comprise from 10% to 20% by weight of (meth) acrylates having at least one double bond in the alkyl radical and from 8 to 40 carbon atoms.

When preparing the core-shell polymers, the composition of the monomer mixture can be varied stepwise, wherein the polymerization is preferably carried out until a conversion of at least 80% by weight, more preferably at least 95% by weight, in each case based on the total weight of the monomer mixture used, before the composition is changed. The core-shell polymers here represent polymers prepared by two-stage or multistage emulsion polymerization, whereas the core-shell structure has not been shown, for example, by means of electron microscopy. The monitoring of the progress of the polymerization reaction in each step can be carried out in a known manner, for example gravimetrically or by means of gas chromatography.

The monomer mixture used for the preparation of the core preferably comprises from 50% to 100% by weight of (meth) acrylates, wherein mixtures of acrylates and methacrylates are particularly preferably used. After the preparation of the core, a monomer mixture comprising from 15% to 28% by weight of a (meth) acrylate having at least one double bond in the alkyl radical and from 8 to 40 carbon atoms can be grafted onto this core or polymerized onto this core.

The emulsion polymerization is preferably carried out at a temperature of from 0 to 120 ℃ and more preferably from 30 to 100 ℃. It has proven very particularly advantageous in this connection to have a polymerization temperature in the range from more than 60 to less than 90 ℃, expediently from more than 70 to less than 85 ℃, preferably from more than 75 to less than 85 ℃.

The polymerization is initiated with the initiators customary for emulsion polymerization. Suitable organic initiators are, for example, hydroperoxides, such as tert-butyl hydroperoxide or cumene hydroperoxide. Suitable inorganic initiators are the alkali metal and ammonium salts of hydrogen peroxide and peroxodisulfuric acid, in particular ammonium peroxodisulfate, sodium peroxodisulfate and potassium peroxodisulfate. Suitable redox initiator systems are, for example, combinations of tertiary amines with peroxides or sodium disulfite and the alkali metal and ammonium salts of peroxodisulfuric acid, in particular sodium and potassium peroxodisulfate. Further details can be taken from the specialist literature, in particular H.Rauch-Puntigam, Th."Acryl-und Methacryl very bingungen" (acrylic and methacrylic compounds), Springer, Heidelberg, 1967 or Kirk-Othmer, Encyclopedia of Chemical Technology, Vol.1, p.386 and subsequent pages, J.Wiley, New York, 1978. The use of organic and/or inorganic initiators is particularly preferred within the scope of the present invention.

The initiators mentioned may be used both individually and in the form of mixtures. They are preferably used in amounts of from 0.05% to 3.0% by weight, based on the total weight of the monomers of the respective stage. It is also preferred that the polymerization can be carried out with a mixture of different polymerization initiators having different half-lives in order to keep the radical flow constant during the polymerization and at different polymerization temperatures.

The stabilization of the batch is preferably carried out using emulsifiers and/or protective colloids. The emulsion is preferably stabilized by emulsifiers to obtain a low dispersion viscosity. The total amount of emulsifiers is preferably from 0.1% to 15% by weight, in particular from 1% to 10% by weight, more preferably from 2% to 5% by weight, based on the total weight of the monomers used. According to a particular aspect of the invention, a portion of the emulsifier may be added during the polymerization.

Particularly suitable emulsifiers are anionic or nonionic emulsifiers or mixtures thereof, especially

Alkyl sulfates, preferably those having from 8 to 18 carbon atoms in the alkyl radical, alkyl-and alkylaryl ether sulfates having from 8 to 18 carbon atoms in the alkyl radical and from 1 to 50 ethylene oxide units;

sulfonates, preferably alkylsulfonates having 8 to 18 carbon atoms in the alkyl radical, alkylarylsulfonates having 8 to 18 carbon atoms in the alkyl radical, esters and half-esters of sulfosuccinic acid with monohydric alcohols or alkylphenols having 4 to 15 carbon atoms in the alkyl radical; where appropriate, these alcohols or alkylphenols may also be ethoxylated with from 1 to 40 ethylene oxide units;

partial phosphates and their alkali metal and ammonium salts, preferably alkyl-and alkylaryl phosphates having from 8 to 20 carbon atoms in the alkyl or alkylaryl radical and from 1 to 5 ethylene oxide units;

alkyl polyglycol ethers, preferably having 8 to 20 carbon atoms in the alkyl radical and 8 to 40 ethylene oxide units;

alkylaryl polyglycol ethers, preferably having from 8 to 20 carbon atoms in the alkyl or alkylaryl radical and from 8 to 40 ethylene oxide units;

ethylene oxide/propylene oxide copolymers, preferably block copolymers, advantageously having from 8 to 40 ethylene oxide and/or propylene oxide units.

Particularly preferred anionic emulsifiers include, in particular, fatty alcohol ether sulfates, diisooctyl sulfosuccinates, lauryl sulfates, C15-paraffin sulfonates, it being possible to use these compounds in the form of their alkali metal salts, in particular their sodium salts, in general. These compounds are commercially available, especially under the trade nameFES 32、OT 75、K1296 andk1 is commercially available from the companies Cognis GmbH, Cytec Industries, Inc. and Bayer AG.

Suitable nonionic emulsifiers include, in particular, tert-octylphenol ethoxylates having 30 ethylene oxide units and fatty alcohol polyglycol ethers preferably having 8 to 20 carbon atoms in the alkyl radical and 8 to 40 ethylene oxide units. These emulsifiers may be sold under the trade nameX 305(Fluka)、15-S-7(Sigma-Aldrich Co.)、1618/25(Sasol Germany) and013/400 (Sasol Germany) is commercially available.

Preferably, mixtures of anionic and nonionic emulsifiers can be used. The weight ratio of anionic emulsifier to nonionic emulsifier may suitably be in the range of from 20: 1 to 1: 20, preferably from 2: 1 to 1: 10, more preferably from 1: 1 to 1: 5. Mixtures which have proven very particularly suitable here are those which comprise sulfates, in particular fatty alcohol ether sulfates, lauryl sulfates, or sulfonates, in particular diisooctyl sulfosuccinate or paraffin sulfonates, as anionic emulsifiers, and alkylphenol ethoxylates or fatty alcohol polyglycol ethers, each preferably having from 8 to 20 carbon atoms in the alkyl radical and from 8 to 40 ethylene oxide units, as nonionic emulsifiers.

Emulsifiers may also be used, where appropriate, in a mixture with protective colloids. Suitable protective colloids include, in particular, partially hydrolyzed polyvinyl acetate, polyvinylpyrrolidone, carboxymethylcellulose, methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, starch, protein, poly (meth) acrylic acid, poly (meth) acrylamide, polyvinylsulfonic acid, melamine-formaldehyde sulfonate, naphthalene-formaldehyde sulfonate, styrene-maleic acid copolymers and vinyl ether-maleic acid copolymers. If protective colloids are used, they are preferably used in amounts of from 0.01 to 1.0% by weight, based on the total amount of monomers. The protective colloid can be initially added or metered in before the polymerization begins. The initiator can be initially charged or metered in. In addition, it is also possible to initially charge a portion of the initiator and to meter in the remainder.

The polymerization is preferably initiated by heating the batch to the polymerization temperature and metering in the initiator, preferably in aqueous solution. The metered feeding of the emulsifier and the monomers can be carried out separately or as a mixture. In the case of the metered addition of a mixture of emulsifier and monomer, the procedure is as follows: the emulsifier and the monomers are premixed in a mixer upstream of the polymerization reactor. Preferably, the remainder of the emulsifier and the monomers not initially charged are metered in separately from one another after the start of the polymerization. The metering can preferably be started 15 to 35 minutes after the start of the polymerization.

Emulsion polymers having a high proportion of insoluble polymer can be obtained in the manner described above, wherein the reaction parameters for obtaining high molecular weights are known. For example, the use of molecular weight regulators can be omitted in this connection, among others.

The adjustment of the particle radius can be influenced in particular via the proportion of emulsifier. The higher this proportion, especially at the start of the polymerization, the smaller the particles obtained.

The aqueous dispersions obtained by the process of the invention can be used as coatings. Thus, aqueous dispersions are a further subject of the present invention. The aqueous dispersion preferably has a solids content of 10% to 70% by weight, more preferably 20% to 60% by weight. The dispersions may suitably have a dynamic viscosity of from 0.1 to 180mPas, preferably from 1 to 80mPas, very particularly preferably from 5 to 20mPas, measured at 25 ℃ in accordance with DINEN ISO 2555 (Brookfield).

In addition, the aqueous dispersions of the invention can be provided in a known manner with additives or other components in order to adapt the properties of the coating to specific requirements. These additional substances include, inter alia, drying aids (so-called siccatives), flow improvers, pigments and dyes.

The coating materials according to the invention preferably have a minimum film-forming temperature of at most 50 ℃, particularly preferably at most 35 ℃, very particularly preferably at most 25 ℃, which can be measured according to DIN ISO 2115.

It is particularly preferred that a siccative can be added to the aqueous dispersion. They include in particular organometallic compounds, examples being transition metals, such as cobalt, manganese, lead, zirconium; metal soaps of alkali or alkaline earth metals, e.g. lithium, potassium and calcium. Examples that may be exemplarily mentioned include cobalt naphthalenedicarboxylate and cobalt acetate. The siccatives can be used individually or as mixtures, with mixtures comprising cobalt, zirconium and lithium salts being particularly preferred.

The aqueous dispersions of the invention can be used in particular as coatings or as additives for them. Such materials include, inter alia, paints, impregnating compositions, adhesives and/or primer systems. It is particularly preferred that the aqueous dispersion can be used for the preparation of a paint or impregnating composition for application on wood and/or metal.

The coatings obtainable from the coatings according to the invention exhibit high solvent resistance, with in particular only a low proportion being dissolved from the coating by the solvent. Preferred coatings exhibit high resistance, especially to methyl isobutyl ketone (MIBK). For example, the weight loss after treatment with MIBK is preferably at most 50 wt.%, more preferably at most 35 wt.%. The absorption of MIBK is preferably up to 300% by weight, particularly preferably up to 250% by weight, based on the weight of the coating used. These values are measured at a temperature of about 25 ℃ and for an exposure time of at least 4 hours, wherein a completely dry coating is measured. Here, this drying is carried out in the presence of oxygen, for example air, so that crosslinking can be achieved.

The coatings obtained from the coatings of the invention exhibit high mechanical stability. The pendulum hardness, measured according to DIN ISO 1522, is preferably at least 20s, more preferably at least 25 s.

The invention will be further elucidated with reference to examples and comparative examples, without being limited thereby.

Detailed Description

Example 1

First, 172g of Butyl Acrylate (BA), 128g of Methyl Methacrylate (MMA), 80g of methacryloxy-2-hydroxypropyl-linoleate, 20g of Methacrylic Acid (MAS), 1.2g of Ammonium Peroxodisulfate (APS), 12.0g of Disponil FES 32 (30% strength) and 359.18g of water were emulsified for 3 minutes in a 2 l PE beaker at 4000rpm using an Ultra-Turrax. Methacryloxy-2-hydroxypropyl-linoleate was obtained by reacting linoleic acid with glycidyl methacrylate.

A2 l glass reactor, tempered with a water bath and equipped with a paddle stirrer, was initially charged with 230g of water and 0.3g of Disponil FES 32 (30% strength) and this initial charge was heated to 80 ℃ and admixed with 0.3g of Ammonium Peroxodisulfate (APS) (in dissolved form in 10g of water). 5 minutes after the addition of APS, the emulsion prepared beforehand was metered in over 240 minutes (interval: 3 minutes of feeding, 4 minutes of pause, 237 minutes of remaining portion of feeding).

After the end of the feed, the batch is poststirred for 1 hour at 80 ℃. Thereafter, it was cooled to room temperature and the dispersion was filtered through a VA mesh fabric having a mesh size of 0.09 mm.

The emulsion prepared had a solids content of 40. + -. 1%, a pH of 2.6, a viscosity of 15mPas and r at 83nm_N5The value is obtained.

Subsequently, the degree of swelling of the emulsion polymer in THF, and the proportion in which it is soluble, were determined. For this purpose, a sample of the emulsion polymer is dried under reduced pressure at 20 ℃. The dried sample had a weight of 0.462 g. This sample was stored in 150ml THF for 4 hours, after which the swollen sample was separated off via a sieve fabric (mesh size 0.09 mm). The swollen sample weight was 5.795g, and was initially at room temperature, followed by drying in a drying oven. The dry sample weight was 0.332 g. This gives a soluble fraction of (0.462-0.332)/0.462 × 100 ═ 28.1%. The swelling degree was (5.975-0.332)/0.332 × 100 ═ 1645%.

The properties of the coatings thus obtained were investigated by different methods. For this purpose, experiments relating to solvent resistance, water absorption and hardness were carried out on the dried films.

Solvent resistance was determined using methyl isobutyl ketone (MIBK) which was used to swell the sample with MIBK at room temperature for 4 hours. Thereafter, the sample was taken out of the solvent and the excess solvent was removed. Subsequently, the sample was dried at about 140 ℃ for 1 hour. The proportion of sample removed by the solvent was calculated from the weight loss.

The water absorption can be measured using test pieces made of untreated solid pine wood (size: 45-50 mm. times.45-50 mm. times.17 mm). The test piece was provided with a paint layer and placed in water at room temperature so that only the coated side was in contact with water. The water absorption was calculated from the weight increase amount of the test piece.

The hardness of the coating, which is typically a measure of scratch resistance, is studied using a pencil hardness test and a pendulum test. The tensile strength of the films is determined according to DIN EN ISO 527, part 3, which is generally a measure of the mechanical stress of the coatings. The results obtained are given in table 1.

Example 2

Example 1 was substantially repeated, but 80g of methacryloxy-2-hydroxypropyl-oleate were used therein. The methacryloxy-2-hydroxypropyl oleate is obtained by the reaction of oleic acid with glycidyl methacrylate.

The emulsion prepared has a solids content of 40. + -. 1%, a pH of 2.5, a viscosity of 16mPas and r at 71nm_N5The value is obtained.

The results obtained with the analytical method described above are given in table 1.

For comparison, a commercially available alkyd resin was investigated, wherein as comparative example 1, an alkyd resin having the designation E150W commercially available from the company Worl é was investigated, and as comparative example 2, Xyladcor, which is marketed by the company ICI, was investigated. The results obtained are described in table 1.

Comparative example 3

First, 216g of Butyl Acrylate (BA), 180g of Methyl Methacrylate (MMA), 4g of Methacrylic Acid (MAS), 1.2g of Ammonium Peroxodisulfate (APS), 12.0g of Disponil FBS32 (30% strength) and 359.18g of water were emulsified for 3 minutes in a 2 liter PE beaker at 4000rpm using an Ultra-Turrax.

A2 l glass reactor, tempered with a water bath and equipped with a paddle stirrer, was charged with 230g of water and 0.3g of Disponil FBS32 (30% strength) and this initial charge was heated to 80 ℃ and admixed with 0.3g of Ammonium Peroxodisulfate (APS) (in dissolved form in 10g of water). 5 minutes after the addition of APS, the emulsion prepared beforehand was metered in over 240 minutes (interval: 3 minutes of feed, 4 minutes of pause, 237 minutes of remaining portion of feed).

After the end of the feed, the batch is poststirred for 1 hour at 80 ℃. Thereafter, cool to room temperature and let the dispersion pass through a VA mesh fabric with a mesh size of 0.09 mm.

The dried film was subjected to experiments relating to solvent resistance, water absorption and scratch resistance.

Table 1: results of Performance Studies

	Example 1	Example 2	Comparative example 1	Comparative example 2	Comparative example 3
						Pendulum hardness [ s ]]	14	13.5	13.3	12.6	7
Hardness of pencil	3H	2H	＜6B	B	-
						Weight loss in MIBK [% ]]	11.7	16.1	47.7	23.5	Dissolution
Weight loss in ethanol [% ]]	14.7	18.5	-	24.0	6.3
						Water absorption after 24h (blank value 38.7%)	22.2％	23.2	45.5％	25.2％	-
Tensile strength [ MPa ]]	3.6	2.7			1.9

Example 3

Example 1 was substantially repeated, wherein the dispersion was prepared via a miniemulsion process. For this purpose, 400g of butyl acrylate, 390g of methyl methacrylate, 200g of methacryloxy-2-hydroxypropyl linoleate and 10g of methacrylic acid are emulsified with 20g of sodium dodecyl sulfate. As a hydrophobing agent, 4% hexadecane was additionally added. The polymerization was initiated with 1% AIBN at 75 ℃. The dispersion obtained had an r of 51nm_N5Value and pH of 4.1. The coating formed from this dispersion showed a weight loss in MIBK of 11.7%, a water absorption after 24h of 22.8% and a tensile strength of 5.1 MPa.

Example 4

Example 1 was substantially repeated, wherein the dispersion was prepared via a miniemulsion process. For this purpose, 400g of butyl acrylate and 390g of methacrylic acid were reacted with 20g of sodium dodecyl sulfateMethyl ester, 200g methacryloxy-2-ethyl-linoleate and 10g methacrylic acid. Methacryloxy-2-ethyl-linoleate was obtained by the reaction of linoleic acid with hydroxyethyl methacrylate. As a hydrophobing agent, 4% hexadecane was additionally added. Polymerization was initiated with 1% AIBN at 75 ℃. The dispersion obtained had an r of 65nm_N5Value and pH of 3.9. The coating formed from this dispersion showed a weight loss in MIBK of 13.6%, a water absorption after 24h of 9.2% and a tensile strength of 2.8 MPa.

Claims (36)

1. Emulsion polymers comprising at least one (meth) acrylate segment comprising

From 1% by weight to 30% by weight of units derived from (meth) acrylates having at least one double bond in the alkyl radical and from 8 to 40 carbon atoms,

from 0.1% to 10% by weight of units derived from acid group-containing monomers, and

from 50% by weight to 98.9% by weight of units derived from (meth) acrylates having from 1 to 6 carbon atoms in the alkyl radical,

characterized in that the emulsion polymer has a particle radius of at least 50nm, based in each case on the weight of the (meth) acrylate segments.

2. An emulsion polymer as claimed in claim 1, characterized in that the (meth) acrylate segment comprises from 2% to 30% by weight of units derived from comonomers, based on the weight of the (meth) acrylate segment.

3. An emulsion polymer as claimed in claim 1 or 2, characterized in that the emulsion polymer has an iodine value of from 5 to 40g per 100g of emulsion polymer.

4. An emulsion polymer according to at least one of the preceding claims, characterized in that the (meth) acrylate containing at least one double bond and 8 to 40 carbon atoms in the alkyl radical is obtainable by reacting at least one unsaturated fatty acid with at least one (meth) acrylate having at least one reactive group in the alcohol residue.

5. An emulsion polymer according to claim 4, characterized in that the (meth) acrylate having at least one reactive group in the alcohol residue is a hydroxyalkyl (meth) acrylate or a (meth) acrylate having at least one epoxy group.

6. An emulsion polymer as claimed in claim 4 or 5, characterized in that said (meth) acrylic acid ester having at least one double bond in the alkyl radical and 8 to 40 carbon atoms is obtainable by reacting an unsaturated fatty acid with glycidyl (meth) acrylate.

7. An emulsion polymer according to at least one of the preceding claims, characterized in that the (meth) acrylate segments comprise units derived from (meth) acryloyloxy-2-hydroxypropyl-linoleate, (meth) acryloyloxy-2-hydroxypropyl-linolenate and/or (meth) acryloyloxy-2-hydroxypropyl-oleate.

8. An emulsion polymer according to claim 7, characterized in that the weight ratio of units derived from (meth) acryloyloxy-2-hydroxypropyl-linoleate to units derived from (meth) acryloyloxy-2-hydroxypropyl-oleate is greater than or equal to 1.

9. An emulsion polymer according to claim 7 or 8, characterized in that the (meth) acrylate segment comprises at least 40% by weight of units derived from (meth) acryloyloxy-2-hydroxypropyl-linoleate, based on the weight of the units derived from the (meth) acrylate containing at least one double bond in the alkyl group and 8 to 40 carbon atoms.

10. An emulsion polymer according to claim 9, characterized in that the (meth) acrylate segment comprises from 45% to 80% by weight of units derived from (meth) acryloyloxy-2-hydroxypropyl-linoleate, based on the weight of the units derived from the (meth) acrylate ester containing at least one double bond in the alkyl group and from 8 to 40 carbon atoms.

11. An emulsion polymer according to at least one of claims 8 to 10, characterized in that the (meth) acrylate segments comprise at least 10% by weight of units derived from (meth) acryloyloxy-2-hydroxypropyl-oleate, based on the weight of the units derived from the (meth) acrylates having at least one double bond in the alkyl group and 8 to 40 carbon atoms.

12. An emulsion polymer according to claim 11, characterized in that the (meth) acrylate segment comprises from 15% to 45% by weight of units derived from (meth) acryloyloxy-2-hydroxypropyl-oleate, based on the weight of the units derived from the (meth) acrylate ester having at least one double bond in the alkyl group and from 8 to 40 carbon atoms.

13. An emulsion polymer according to at least one of the preceding claims, characterized in that the (meth) acrylate segments comprise up to 30% by weight of units derived from styrene, substituted styrenes having alkyl substituents in the side chains, substituted styrenes having alkyl substituents in the ring and/or halogenated styrenes, based on the weight of the (meth) acrylate segments.

14. An emulsion polymer according to at least one of the preceding claims, characterized in that the (meth) acrylate segment comprises up to 10% by weight of units derived from a (meth) acrylate obtainable by reacting a saturated fatty acid with at least one (meth) acrylate containing a reactive group in the alcohol residue, based on the weight of the (meth) acrylate segment.

15. An emulsion polymer as claimed in claim 14, characterized in that said (meth) acrylate segment comprises from 0.1% to 3% by weight, based on the weight of said (meth) acrylate segment, of units derived from a (meth) acrylate obtainable by reacting a saturated fatty acid with at least one (meth) acrylate containing a reactive group in the alcohol residue.

16. An emulsion polymer as claimed in claim 14 or 15 characterised in that said saturated fatty acid has from 10 to 26 carbon atoms.

17. An emulsion polymer according to at least one of claims 14 to 16, characterized in that the (meth) acrylic esters are obtainable by reacting saturated fatty acids with glycidyl (meth) acrylate.

18. An emulsion polymer according to at least one of the preceding claims, characterized in that the (meth) acrylate segments are grafted onto the core or polymerized onto the core.

19. An emulsion polymer as claimed in claim 18 characterised in that said core comprises from 50% to 100% by weight of units derived from a (meth) acrylate.

20. An emulsion polymer according to claim 18 or 19, characterized in that the core comprises units derived from an acrylate and units derived from a methacrylate.

21. An emulsion polymer according to at least one of claims 18 to 20, characterized in that the core is crosslinked.

22. An emulsion polymer according to at least one of claims 18 to 21, characterized in that the (meth) acrylate segments comprise from 15% to 28% by weight of units derived from (meth) acrylates having at least one double bond in the alkyl group and from 8 to 40 carbon atoms.

23. An emulsion polymer according to at least one of the preceding claims, characterized in that the (meth) acrylate segments comprise from 1% to 5% by weight of units derived from acid group-containing monomers, based on the total weight of the (meth) acrylate segments.

24. An emulsion polymer according to at least one of the preceding claims, characterized in that the (meth) acrylate segment comprises from 10% by weight to 20% by weight of units derived from a (meth) acrylate having at least one double bond in the alkyl group and from 8 to 40 carbon atoms, based on the total weight of the (meth) acrylate segment.

25. An emulsion polymer according to at least one of the preceding claims, characterized in that the (meth) acrylate segments comprise units derived from acrylates and units derived from methacrylates.

26. An emulsion polymer according to at least one of the preceding claims, characterized in that 2% to 60% by weight of the emulsion polymer is soluble in Tetrahydrofuran (THF) at 20 ℃.

27. An emulsion polymer according to at least one of the preceding claims, characterized in that the emulsion polymer exhibits a swelling degree of at least 1000% in Tetrahydrofuran (THF) at 20 ℃.

28. Aqueous dispersion comprising an emulsion polymer according to at least one of the preceding claims.

29. Aqueous dispersion according to claim 28, characterized in that the aqueous dispersion has a dynamic viscosity of 1 to 80 mPas.

30. Aqueous dispersion according to claim 28 or 29, characterized in that the aqueous dispersion has a solids content of 20% to 60% by weight.

31. Method for preparing an aqueous dispersion according to any of claims 28 to 30, characterized in that a mixture comprising an aqueous phase and a monomer-containing phase is prepared and the monomers of the monomer-containing phase are polymerized, characterized in that a monomer mixture is used which comprises:

from 1% by weight to 30% by weight of a (meth) acrylate having at least one double bond in the alkyl radical and from 8 to 40 carbon atoms,

from 0.1% to 10% by weight of monomers containing acid groups, and

50% to 98.9% by weight of a (meth) acrylate having 1 to 6 carbon atoms in the alkyl radical.

32. The method according to claim 31, characterized in that the monomer mixture comprises 1% to 5% by weight of acid group-containing monomers.

33. The process according to claim 31 or 32, characterized in that a monomer mixture comprising 10% to 20% by weight of a (meth) acrylate ester having at least one double bond in the alkyl group and 8 to 40 carbon atoms is used.

34. The process according to at least one of claims 31 to 33, characterized in that the core is first prepared with a monomer mixture comprising 50% to 100% by weight of (meth) acrylates having 1 to 6 carbons in the alkyl group.

35. The method according to claim 34, characterized in that the monomer mixture used for preparing the core comprises acrylates and methacrylates.

36. The process according to any one of claims 34 or 35, characterized in that a monomer mixture is grafted onto the core or polymerized onto the core, the core comprising from 15% to 28% by weight of a (meth) acrylate ester containing at least one double bond in the alkyl group and from 8 to 40 carbon atoms.