EP1727834A1

EP1727834A1 - Aqueous polymer dispersion containing effect materials method for production and use thereof

Info

Publication number: EP1727834A1
Application number: EP05731798A
Authority: EP
Inventors: Rainer Dyllick-Brenzinger; Alban Glaser; Arno BÖHM
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 2004-03-12
Filing date: 2005-03-09
Publication date: 2006-12-06
Also published as: BRPI0508516A; RU2395526C2; RU2006135932A; JP4575432B2; DE102004012576A1; CN100535021C; US20070218089A1; CN1930192A; JP2007528926A; WO2005087816A1; IL177653A0

Abstract

The invention relates to an aqueous polymer dispersion containing effect materials with an average particle diameter for the dispersed particles of < 500 nm, said polymer particles comprising a core of a polymer matrix made up of at least one ethylenically-unsaturated monomer, on the surface of which an effect material is at least partly arranged, which is soluble in the monomers which form the particles of the polymer matrix, a method for production of such a polymer dispersion by mini-emulsion polymerisation of ethylenically-unsaturated monomers, whereby a mini-emulsion with a mean particle size for the emulsified particles of < 500 nm is produced by emulsification of ethylenically-unsaturated monomers in water in the presence of at least one effect material and one surface active material and the above is polymerised in the presence of at least one radical polymerisation initiator such that, firstly, only a maximum of 50 % of the monomers in the polymerisation zone polymerise and the effect materials migrate to the surface of the emulsified particles, the polymerisation being only complete after extensive or complete aggregation of the effect material on the surface of the generated polymer particles and use of the dispersion, or of a powder obtained by evaporation of water to stabilise the polymers against the effects of UV radiation, acids and heat, in cosmetic and pharamceutical formulations, in paint coatings, in the production of paper, leather and textiles and formulations for animal feedstuffs.

Description

Aqueous polymer dispersions containing effect substances, process for their preparation and their use

description

The invention relates to aqueous polymer dispersions containing effect substances, a process for the preparation of these aqueous polymer dispersions by mini-emulsion polymerization of ethylenically unsaturated monomers in the presence of effect substances and the use of polymers containing effect substances for stabilizing polymers against the action of UV radiation, oxygen and heat cosmetic and pharmaceutical formulations, in lacquer layers, in the manufacture of paper, leather and textiles and in formulations for animal nutrition.

From JP-A-7-292009 aqueous polymer dispersions are known which contain functional substances such as in particular UV absorbers or epoxy resins. They are prepared by dissolving the functional substances in an unsaturated monomer, emulsifying this solution in water in the presence of a surface-active agent to give a monomer emulsion with average particle sizes between 5 and 500 nm, and polymerizing the miniemulsion in the presence of a radical initiator. The aqueous dispersions, which contain the functional substances such as UV absorbers, epoxy resins, acrylic-based polymers, phenolic resins, unsaturated polyesters, phenolic-based substances and petroleum resins, are used as binders and as additives for protective film.

From WO-A-99/40123 a process for the production of aqueous polymer dispersions is known, the dispersed polymer particles of which contain an organic dye homogeneously, ie distributed in a molecular dispersion. Such aqueous dispersions are prepared by mini-emulsion polymerization by polymerizing ethylenically unsaturated monomers which contain an organic dye in solution in the form of an oil-in-water emulsion in the presence of radical-forming polymerization initiators, the disperse phase of the emulsion being essentially composed of dye containing monomer droplets with a diameter <500 nm is formed. In an advantageous embodiment of the invention, monomer mixtures which contain crosslinking monomers are used in the polymerization. The polymer dispersions are stable to sedimentation. The dispersed particles have an average particle diameter of 100 to 400 nm. They can be obtained from the aqueous dispersions using conventional drying methods. The dye-containing polymer dispersions are used, for example, for pigmenting high molecular weight organic and inorganic materials, for pigmenting printing inks and inks for ink-jet printing. From EP-A-1 092416 the use of dyes, optical brighteners or UV absorbers containing finely divided, aqueous polymer dispersions or a powdery polymer obtainable therefrom, the polymer matrix of which contains dyes, optical brighteners or UV absorbers homogeneously distributed, as a coloring component in known cosmetic products. The dispersions are preferably prepared by the process known from WO-A-99/40123 by mini-emulsion polymerization of ethylenically unsaturated monomers which contain a dye, optical brightener or UV absorber in solution.

Further colorant-containing polymer dispersions, the colorant-containing polymer particles of which have an average particle diameter below 1000 nm, are known from EP-A-1 191 041. In addition to organic dyes, UV absorbers and optical brighteners can also be used as colorants. They are obtained by dissolving a colorant in at least one ethylenically unsaturated monomer, emulsifying this solution in water to form a conventional macroemulsion, homogenizing the macroemulsion to form a miniemulsion with an average droplet size below 1000 nm and polymerizing the miniemulsion in the presence of a radical-forming polymerization initiator, 0.1 to 20% by weight of at least one nonionic surface-active compound and 1 to 50% by weight, based in each case on the monomers used, of at least one amphiphilic polymer. The polymer particles contain 0.5 to 50% by weight, homogeneously distributed, of at least one organic dye, optical brightener or UV absorber, which is to be understood to mean that the organic colorants are monomolecularly dissolved in the polymer matrix or in the form of bi- or higher molecular weight Aggregates are present.

WO-A-01/10936 discloses particles with a core / shell structure, in which the core comprises a polymer with a glass transition temperature T _g of below 40 ° C. and a UV absorber and the shell preferably consists of a polymer made from methyl acrylate , Ethyl acrylate, ethyl methacrylate and / or methyl methacrylate. The polymer that forms the core of the particle can optionally be cross-linked. The polymer particles are made by emulsion polymerization. The polymer particles containing UV absorbers are used to produce UV-absorbing polymer compositions.

Aqueous polymer dispersions containing alkyldiketenes are known from the older DE application 10248 879.7, which can be obtained by miniemulsion polymerization of hydrophobic monoethylenically unsaturated monomers in the presence of alkyldiketenes. These dispersions are used as sizing agents for paper, as water repellents for leather, natural and / or synthetic fibers and textiles. The older DE application 102 54 548.0 discloses the use of finely divided polymer powders containing at least one UV absorber for stabilizing polymers against the action of UV radiation. The polymer particles of the polymer powders have a particle size of 500 nm or less. They are preferably produced by mini-emulsion polymerization using processes which are known from the abovementioned documents WO-A-99/40123, EP-A-1 092415 and EP-A-1 191 041. The polymer particles contain 0.5 to 50% by weight of at least one UV absorber, which is either homogeneously distributed therein in molecular or nanocrystalline form or is completely or only partially enveloped by the polymer matrix.

US Pat. No. 6,309,787 discloses a process for encapsulating dyes by mini-emulsion polymerization, the mini-emulsion being prepared in the presence of a surface-active agent, a co-surfactant and a nonionic surface-active agent. After the polymerization, dispersed particles are obtained which are composed of a dye core and a polymer shell.

DE-A-196 28 143 discloses a process for the preparation of an aqueous polymer dispersion. The monomers are polymerized in the manner of a free-radical aqueous miniemulsion polymerization, in which at least part of the aqueous monomer miniemulsion is fed continuously to the polymerization zone with continuous polymerization.

The object of the present invention is to provide aqueous polymer dispersions containing further effect substances.

The object is achieved according to the invention with aqueous polymer dispersions containing effect substances with an average particle diameter of the dispersed particles of <500 nm, the polymer particles containing as core a polymer matrix composed of at least one ethylenically unsaturated monomer, on the surface of which an effect substance is at least partially arranged is soluble in the monomers that form the polymer matrix of the particles. The effect substances are preferably arranged as a shell around the core of the polymer particles.

The invention also relates to a process for the preparation of finely divided aqueous polymer dispersions containing effect substances with an average particle diameter of the dispersed polymer particles of <500 nm by miniemulsion polymerization of ethylenically unsaturated monomers, if by emulsifying ethylenically unsaturated monomers in water in the presence of at least one Effect substance and a surfactant produces a mini emulsion with an average particle size of the emulsified particles of <500 nm, and so polymerizes in the presence of at least one radical polymerization initiator, that initially only polymerize a maximum of 50% of the monomers that are in the polymerization zone and the effect substances migrate to the surface of the emulsified particles, and the polymerization only after the effect substances have largely or completely accumulated on the surface of the resulting polymer particles.

In the context of the invention, effect substances are to be understood as products which are selected, for example, from the group of UV absorbers, organic dyes, optical brighteners, stabilizers and auxiliaries for organic polymers, IR dyes, flame retardants, alkenylsuccinic anhydrides, active pharmaceutical ingredients and biocides. The effect substances in question are soluble in the ethylenically unsaturated monomers which form the core of the polymer particles of the aqueous dispersion. The solubility of the effect substances in the monomers is at a temperature of 20 ° C. and a pressure of 1 bar, for example at least 1 g / l, preferably at least 10 g / l. The amount of the effect substances which is arranged on the surface of the dispersed polymer particles is, for example, 0.5 to 50% by weight, preferably 2 to 20% by weight, based on the polymer matrix.

The mini-emulsion polymerization of ethylenically unsaturated monomers in the presence of oil-soluble dyes is known, for example, from WO-A-99/40123 cited in the prior art. Because of the details of this polymerization method, particular reference is made to page 3, line 30 to page 38, line 6 and to page 69, line 11 to page 84, line 43 of WO-A-99/40123. This part of the WO application is hereby made by reference to the disclosure content of the present invention. The ethylenically unsaturated monomers, non-polymerizable organic dyes, auxiliaries and process measures for producing the miniemulsion described there are used in the same way in the process according to the invention. According to the invention, the essential difference from the known process consists in the special implementation of the polymerization. In addition to an oil-soluble, non-polymerizable dye, other effect substances which are also soluble in ethylenically unsaturated monomers can be used in the process according to the invention. UV absorbers, which are also oil-soluble and are preferably dissolved in the monoethylenically unsaturated monomers from which the core of the polymers is essentially formed, are particularly preferably used as effect substances. UV absorbers are commercial products. For example, they are sold under the trademark Uvinul® by BASF Aktiengesellschaft, Ludwigshafen. As is known, UV absorbers are understood to mean compounds which absorb UV rays and deactivate the absorbed radiation without radiation. UV absorbers absorb light of the wavelength <400 nm and convert it into heat radiation. Such compounds are used, for example, in sunscreens and for stabilizing organic polymers. Examples of UV absorbers are derivatives of p-aminobenzoic acid, in particular their esters, for example ethyl 4-aminobenzoate and ethyl ethoxylated 4-aminobenzoate, salicylates, substituted cinnamates (cinnamates) such as octyl-p-methoxycinnamate and 4-isopentyl-4-methoxycinnam , 2-phenylbenzimidazole-5-sulfonic acid and its salts. A particularly preferred UV absorber is 4-n-octyloxy-2-hydroxy-benzophenone. Other examples of UV absorbers are:

substituted acrylates, e.g. Ethyl or isooctyl-α-cyano-y-., _-Diphenyl acrylate (mainly 2-ethylhexyl-α-cyano-jf, -diphenyl acrylate), methyl α-methoxycarbonyl - ^ - phenyl acrylate, methyl α-methoxycarbonyl- 0- (p-methoxyphenyl) acrylate, methyl or butyl-α-cyano-j-Nmethyl-? - (p-methoxyphenyl) acrylate, NG -? - methoxycarbonyl- -cyanovinyl) -2-methylindoline, octyl-p-methoxycinnamate , isopentyl-4-methoxycinnamate, urocanic acid and its salts and esters;

2-hydroxybenzophenone derivatives, e.g. 4-hydroxy, 4-methoxy, 4-octyloxy, 4-decyloxy, 4-dodecyloxy, 4-benzyloxy, 4,2 ', 4'-trihydroxy, 2'-hydroxy-4,4' di-methoxy-2-hydroxybenzophenone and 4-methoxy-2-hydroxybenzophenone sulfonic acid sodium salt;

Esters of 4,4-diphenylbutadiene-1,1-dicarboxylic acid, e.g. the bis (2-ethylhexyl) ester;

2-phenylbenzimidazole-4-sulfonic acid and 2-phenylbenzimidazole-5-sulfonic acid and its salts;

Derivatives of benzoxazoles;

Derivatives of benzotriazoles and 2- (2'-hydroxyphenyl) benzotriazoles, such as 2- (2H-benzotriazol-2-yl) -4-methyl-6- (2-methyl-3- ((1, 1, 3,3-tetramethyl) -1- (trimethylsilyloxy) disiloxanyl) propyl) phenol, 2- (2'-hydroxy-5'-methylphenyl) benzotriazole, 2- (3 ', 5'-di-tert-butyl-2'- hydroxyphenyl) benzotriazole, 2- (5'-tert-butyl-2'-hydroxyphenyl) benztriazole, 2- [2'-hydroxy-5 '- (1, 1, 3,3-tetramethylbutyl) phenyl] benzotriazole, 2- (3 ', 5'-di-tert-butyl-2'-hydroxyphenyl) -5-chlorobenzotriazole, 2- (3'-tert-butyl-2'-hydroxy-5'-methylphenyl) -5- chlorobenzotriazole, 2- (3'-sec.-butyl-5'-tert.-butyl-2'-hydroxyphenyl) benzotriazole, 2- (2'-hydroxy-4'-octyloxyphenyl) benzotriazole, 2- (3 ' , 5'-di-tert-amyl-2'-hydroxyphenyl) benzotriazole, 2- [3 ', 5'-bis (α, α-dimethylbenzyl) -2'-hydroxyphenyl] benzotriazole, 2- [3'-tert-butyl-2'-hydroxy-5 '- (2-octyloxycarbonylethyl) phenyl] - 5-chlorobenzotriazole, 2- [3'-tert-butyl-5' - (2- (2nd -ethylhexyloxy) - carbonylethyl) -2'-hydroxyphenyl] -5-chlorobenzthazole, 2 [3'-tert-butyl-2'-hydroxy-5 '- (2-methoxycarbonylethyl) phenyl] -5-chlorobenzthazole, 2- [ 3'-tert-butyl-2 ^, -hydroxy-5 '- (2-methoxycarbonylethyl) phenyl] benzotriazoI, 2- [3'-tert-butyl-2'-hydroxy-5' - (2-octyloxycarbonylethyl) phenyl ] benzotriazole, 2- [3'-tert-butyl-5 '- (2- (2-ethylhexyloxy) carbonylethyl) -2'-hydroxyphenyl] benzotriazole, 2- (3'-dodecyl-2'-hydroxy- 5'-methylphenyl) benzotriazole, 2- [3'-tert-butyl-2 ^, -hydroxy-5 ^, - (2-isooctyloxycarbonylethyl) - phenyl] - benztriazole, 2,2'-methylene-bis [4- (1.1 _I 3,3-tetramethylbutyl) -6-benzotriazol-2-yl-phenol], the fully esterified product of 2- [3'-tert-butyl-5 '- (2-methoxycarbonylethyl) -2'- hydroxyphenyl] -2H-benzotriazole with polyethylene glycol 300, [R-CH ₂ CH ₂ -COO (CH ₂ ) ₃ -] ₂ with R equal to 3'-tert-butyl-4-hydroxy-5'-2H-benzotriazole-2 -ylphenyl, 2- [2'-hydroxy-3 '- (α, α- di methylbenzyl) -5 '- (1, 1, 3,3-tetramethylbutyl) phenyl] benzotriazole, 2- [2'-hydroxy-3'- (1,1,3,3-tetramethylbutyl) -5' - (α, α-dimethylbenzyl) phenyl] benzotriazole;

Benzylidene camphor and its derivatives, such as z. B. are mentioned in DE-A 3836 630, e.g. 3-benzylidene camphor, 3 (4'-methylbenzylidene) d-1-camphor;

α- (2-oxoborn-3-ylidene) toluoI-4-sulfonic acid and its salts, N, N, N-trimethyl-4- (2-oxoborn-3-ylidene methyl) anilinium methosulfate;

Dibenzoylmethanes, e.g. 4-tert-butyl-4'-methoxydibenzoylmethane;

2,4,6-triaryltriazine compounds such as 2,4,6-tris- {N- [4- (2-ethylhex-1-yl) oxycarbonylphenyl] amino} -1, 3,5-triazine, 4,4 ' - ((6- (((tert-Butyl) aminocarbonyl) phenylamino) -1, 3,5-triazine-2,4-diyl) imino) bis (2'-ethylhexyl benzoate); and

2- (2-hydroxyphenyl) -1,3,5-thazines, such as 2,4,6-tris (2-hydroxy-4-octyloxyphenyl) 1,3,5-triazine, 2- (2-hydroxy-4 -octyloxyphenyl) -4,6-bis (2,4-dimethylphenyl) -1, 3,5-triazine, 2- (2,4-dihydroxyphenyl) -4,6-bis (2,4-dimethylphenyl) - 1, 3,5-triazine, 2,4-bis (2-hydroxy-4-propyloxyphenyl) -6- (2,4-dimethylphenyl) -1, 3,5-triazine, 2- (2-hydroxy-4-octyloxyphenyl ) -4,6-bis (4-methylphenyl) - 1,3,5-triazine, 2- (2-hydroxy-4-dodecyloxyphenyl) -4,6-bis (2,4-dimethylphenyl) -1,3, 5-triazine, 2- [2-hydroxy-4- (2-hydroxy-3-butyloxypropyloxy) phenyl] -4,6-bis (2,4-dimethylphenyl) -1,3,5-triazine, 2- [2 - hydroxy-4- (2-hydroxy-3-octyloxypropyloxy) phenyl] -4,6-bis- (2,4-dimethylphenyl) -1, 3,5-triazine, 2- (2-hydroxy-4- tridecyloxyphenyl) -4,6-bis (2,4-dimethylphenyl) -1, 3,5-thazine, 2- [4- (dodecyloxy / tridecyloxy-2-hydroxypropoxy) -2-hydroxyphenyl] -4,6-bis ( 2,4-dimethylphenyl) -1,3,5-triazine, 2- [2-hydroxy-4 (2-hydroxy-3-dodecyloxypropoxy) phenyl] -4,6-bis- (2,4-dimethylphenyl) -1,3,5-triazine, 2- (2-hydroxy-4-hexyloxyphenyl) -4,6-dipheny l-1,3,5-triazine, 2- (2-hydroxy-4-methoxyphenyl) 4,6-diphenyl-1,3,5-triazine, 2,4,6- Tris [2-hydroxy-4- (3-butoxy-2-hydroxypropoxy) phenyl] -1, 3,5-triazine, 2- (2-hydroxyphenyl) -4- (4-methoxyphenyl) -6-phenyl- 1,3,5-triazine, 2- {2-hydroxy-4- [3- (2-ethylhexyl-1-oxy) -2-hydroxypropyloxy] phenyl} -4,6- bis (2,4-dimethylphenyl) - 1, 3,5-triazine.

Further suitable UV absorbers can be found in Cosmetic Legislation, Vol. 1, Cosmetic Products, European Commission 1999, pp. 64-66, to which reference is hereby made.

Suitable UV absorbers are also described in lines 14 to 30 on page 6 of EP-A-1 191 041.

Other effect substances are organic dyes and optical brighteners, which each dissolve in ethylenically unsaturated monomers and which are themselves not polymerizable. Such dyes and optical brighteners are described in detail in WO-A-99/40123, page 10, line 14 to page 25, line 25, which are referred to in the prior art and to which reference is once again expressly made here. While organic dyes have an absorption maximum in the wavelength range from 400 to 850 nm, optical brighteners have one or more absorption maxima in the range from 250 to 400 nm. As is known, optical brighteners emit fluorescent radiation in the visible range when irradiated with UV light. Examples of optical brighteners are compounds from the classes of bisstyrylbenzenes, stilbenes, benzoxazoles, coumarins, pyrenes and naphthalenes. Commercial optical brighteners are sold under the brands Tinopal® (Ciba), Ultraphor® (BASF Aktiengesellschaft) and Blankophor® (Bayer). Optical brighteners are also described in Römpp, 10th edition, volume 4, 3028-3029 (1998) and in Ullmanns, Encyclopedia of Industrial Chemistry, vol. 24, 363-386 (2003).

Stabilizers for organic polymers are also suitable as effect substances. These are compounds that stabilize polymers against degradation when exposed to oxygen, light or heat. Such stabilizers are also referred to as antioxidants or as UV and light stabilizers, cf. Ullmanns, Encyclopadia of Industrial Chemistry, Vol. 3, 629-650 (ISBN-3-527-30385-5) and EP-A-1 110 999, page 2, line 29 to page 38, line 29. With such stabilizers practically all organic polymers are stabilized, cf. EP-A-1 110 999, page 38, line 30 to page 41, line 35. This reference is also by the

Reference is made to the disclosure content of the present invention. The stabilizers described in the EP application belong to the class of compounds of pyrazolones, organic phosphites or phosphonites, sterically hindered phenols and sterically hindered amines (stabilizers of the so-called HALS type, cf. Römpp, 10th edition, volume 5, Pages 4206-4207 Commercial stabilizers and Aids are sold under the Tinuvin® and Cyasorb® brands from Ciba and Tenox® brands from Eastman Kodak. Stabilizers and auxiliaries are described, for example, in Plastic Additives Handbook, 5th edition, Hanser, ISBN 1-56990-295-X. The stabilizers and auxiliaries are soluble in ethylenically unsaturated monomers, with at least 1 g / l, preferably at least 10 g / l, dissolving at a temperature of 20 ° C. and a pressure of 1 bar.

Other suitable effect substances are IR dyes, which are sold, for example, by BASF Aktiengesellschaft as Lumogen® IR, and flame retardants, for example in Römpp, 10th edition, pages 1352 and 1353 and in Ullmanns, Encyclopedia of Industrial Chemistry, Vol. 14, 53-71. The flame retardants in question are soluble in ethylenically unsaturated monomers.

Effect substances are also to be understood as meaning alkenylsuccinic anhydrides which are known, for example, as mass sizing agents for paper and are used industrially on a large scale. Examples of such sizing agents are the isomers 4-, 5-, 6-, 7- and 8-hexadecenyl succinic anhydrides, decenyl succinic anhydride, octenyl succinic anhydride, dodecenyl succinic anhydride and n-hexadecenyl succinic anhydride, cf. also C.E. Farley and R.B. Wasser, The Sizing of Paper, Second Edition, (3), Sizing With Alkenyl Succinic Anhydride, TAPPI PRESS, 1989, ISBN 0-89852-051-7.

In addition, all pharmaceutical active ingredients which are soluble in ethylenically unsaturated monomers can be used as effect substances. An overview of pharmaceutical active substances can be found, for example, in Römpp, 10th edition, volume 4, page 3235 (ISBN-3- 13-734910-9) and in Ullmanns, Encyclopedia of Industrial Chemistry, Vol. 25, 549 - 579 (2003 ). In the present context, pharmaceutical active ingredients are also to be understood as vitamins. Vitamins are soluble in ethylenically unsaturated monomers. A summary of vitamins can be found, for example, in Römpp, 10th edition, volume 6, pages 4877-4887 (1999) and in Ullmanns, Encyclopedia of Industrial Chemistry, Vol. 38, 109-294.

Other suitable effect substances are perfumes, cf. Ullmanns, Encyclopedia of Industrial Chemistry, Vol. 14, 73-199, and biocides, cf. Ullmanns, Encyclopedia of Industrial Chemistry, Vol. 5, 269-280. The core of the dispersed particles is essentially made of a polymer

(a) at least one ethylenically unsaturated monomer A with a water solubility of> 0.01 g / l, if appropriate

(b) at least one ethylenically unsaturated monomer B with a water solubility of <0.01 g / l and optionally

(c) at least one ethylenically unsaturated monomer with at least two double bonds

built up. The water solubility of the monomers relates in each case to the solubility of the monomers in water at a temperature of 25 ° C. and a pressure of 1 bar.

In most cases, the dispersed polymer particles contain

(a) 50 to 99.5% by weight of at least one monomer A,

(b) 0.5 to 50% by weight of at least one monomer B and

(c) 0 to 30% by weight of at least one monomer C

in polymerized form.

The monomers under consideration are described in detail in WO-A-99/40123, page 4, line 41 to page 10, line 12, which is referred to again at this point. Individual monomers of groups (a) to (c) should be mentioned merely by way of example, specifically as monomers of group (a) styrene, σ-methylstyrene, vinyl acetate, vinyl propionate, dimethyl maleate, diethyl maleate, esters from ethylenically unsaturated C ₃ - bis C ₅ carboxylic acids and monohydric alcohols with 1 to 6 carbon atoms and allyl acetate.

The monomers (a) also include those monomers A ^' which have an increased solubility in water, ie> 60 g / l at 25 ° C. and 1 bar. The monomers A ^' are used to modify the polymers and are usually involved in the structure of the polymer matrix in amounts of 0.1 to 20% by weight, preferably 0.5 to 10% by weight. Examples of these monomers are acrylic acid, methacrylic acid, styrenesulfonic acid, 2-acrylic-2-methylpropanesulfonic acid and vinylphosphonic acid and also cationic monomers such as dimethylaminoethyl acrylate or 1-vinylimidazole and N-vinylformamide and N-vinylpyrrolidone. The basic monomers are used in the form of the free bases, as a salt or in quaternized form in the polymerization. The monomers containing acid groups can be used in the polymerization in the form of the free acids or in a form partially or completely neutralized with alkali metal bases or ammonium bases. Suitable monomers of group (b) are, for example, 2- and 4-methylstyrene, p-tert-butylstyrene, esters of ethylenically unsaturated C ₃ to C ₅ carboxylic acids and alcohols with more than 12 C atoms in the molecule, vinyl laurate, Vinyl stearate and macromonomers such as oligopropene acrylate.

Examples of monomers of group (c) are glycol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, butanediol diacrylate, allyl acrylate, di-vinylbenzene, divinyl urea and methylenebisacrylamide.

For example, the polymer matrix of the dispersed polymer particles can be made from a polymer

(a) methyl methacrylate, styrene, vinyl acetate, methyl acrylate, ethyl methacrylate, acrylic acid and / or methacrylic acid, optionally (b) lauryl acrylate, palmitylacrylate and / or stearyl acrylate and optionally (c) butanediol diacrylate, divinylbenzene, pentaerythritol / dertraacrylate

be constructed.

The polymer matrix of the particles dispersed in water preferably consists of a copolymer which is obtained by polymerizing

(a) methyl methacrylate, ethyl methacrylate and / or acrylic acid, (b) stearyl acrylate and / or palmity acrylate and

(c) butanediol diacrylate, pentaerythritol tetraacrylate and / or pentaerythritol triacrylate

is available.

The aqueous polymer dispersions according to the invention contain dispersed particles with an average particle diameter <500 nm, preferably 50 to 400 nm. The polymer particles essentially consist of a polymer core, on the surface of which at least one effect substance is arranged. Ideally, the effect fabric forms a shell around the polymer core. Such a structure of polymer particles can be seen in FIG. 1. It is an electron micrograph of a section of a powder sample obtained from an aqueous polymer dispersion by distilling off the water. The effect substances are practically incompatible with the polymer or insoluble in the polymer which forms the core of the dispersed particle. They can therefore be found on or on the surface of the polymer matrix as a nanoscale shell. Aqueous polymer dispersions whose dispersed polymer particles consist of a polymer are particularly preferred

(a) methyl methacrylate or methyl methacrylate and acrylic acid, (b) optionally stearyl acrylate and

built up and coated with a shell made of a UV absorber, in particular 4-n-octyloxy-2-hydroxy-benzophenone.

The monomers are used in the polymerization, for example, in amounts such that the resulting polymers

(a) 50 to 99.5% by weight, preferably 80 to 99% by weight, of at least one monomer A and

(b) contain 0.5 to 50% by weight, preferably 1 to 20% by weight, of at least one monomer B in copolymerized form.

The polymer matrix which forms the core of the dispersed particles preferably contains a monomer (c) copolymerized in an amount of 0.1 to 30% by weight, in particular 0.5 to 20, usually 1 to 10% by weight.

The aqueous polymer dispersions according to the invention containing effect substances and having an average particle diameter of the dispersed polymer particles of <500 nm are prepared by mini-emulsion polymerization of ethylenically unsaturated monomers. Here one proceeds, for example, by first dissolving at least one effect substance in at least one monomer. The effect substances are in most cases monomolecularly dissolved, but can also be present in a colloidally dispersed form. The monomer solutions containing the effect substances are then emulsified in water in the presence of at least one surface-active agent. Instead of or in addition to a surface-active agent, microparticles or nanoparticles which are insoluble in water and / or the monomers can also be used as stabilizers for the emulsion (Pickering effect). Stabilizers of this type are, for example, nanoscale silicon dioxide, aluminum oxide and magnesium sulfate. A miniemulsion with an average particle size of the emulsified droplets of <500 nm is obtained. The emulsification is carried out by methods which are described in detail in WO-A-99/40123, page 26, line 11 to page 32, line 4. For example, high-pressure homogenizers of various types are used for emulsification, or ultrasound is applied to a macroemulsion which contains at least one effect substance, which is dissolved in at least one monomer, and water as essential constituents. In the in most cases the mixture is emulsified in the presence of a surfactant. However, it is also possible to dose the effect substances to the mini emulsion. However, as described above, they are preferably first dissolved in at least one monomer and emulsified in water in dissolved or colloidally dispersed form.

The aqueous phase which is used to prepare the mini-emulsions consists of water and optionally contains a surface-active agent which stabilizes the finely divided monomer droplets formed in the emulsion of the organic phase in the aqueous phase. The surface-active agent is used, for example, in amounts of up to 15% by weight, for example from 0.05 to 15% by weight, preferably 0.05 to 5 and in particular 0.1 to 2% by weight, based on the entire dispersion. It is found either in the aqueous phase, the organic phase or in both phases. It is preferably added to the aqueous phase before emulsification. In principle, all surfactants can be used. Surface-active agents used with preference are anionic compounds. Examples of suitable surface-active agents are sodium lauryl sulfate, sodium dodecyl sulfate, sodium hexadecyl sulfate, sodium dioctyl sulfosuccinate and / or addition products of 15 to 50 moles of ethylene oxide with 1 mole of a C ₁₂ to C ₂₂ alcohol.

In order to stabilize a miniemulsion, at least one non-polymerizable hydrophobic compound, for example a hydrocarbon, an alcohol having 10 to 24 carbon atoms, hydrophobic polymers with molecular weights M _w of <50,000, preferably <10,000, are used in the preparation of these emulsions , Tetraalkylsilanes and / or mixtures of the compounds mentioned. Examples of such stabilizers are hexadecane, decahydronaphthalene, olive oil, polystyrene with an average molecular weight M _w <50,000, preferably from 500 to 5000, siloxanes with a molecular weight Mw from 500 to 5000, poly-n-butyl acrylate such as Acronal® A 150 F, Cetyl alcohol, stearyl alcohol, palmityl alcohol and / or behenyl alcohol. The hydrophobic, non-polymerizable compounds are used optionally. They have a water solubility of <0.1 g / l at 25 ° C and 1 bar. If they are used, they are used in amounts of, for example, 1 to 20, usually 1 to 10 and preferably 2 to 6% by weight, based on the monomers used in the polymerization.

In order to obtain stable aqueous polymer dispersions, the polymerization can optionally also be carried out in the presence of protective colloids. They generally have average molecular weights M _w of above 500, preferably more than 1000. Examples of protective colloids are polyvinyl alcohols, cellulose derivatives such as carboxymethyl cellulose, polyvinyl pyrrolidone, polyethylene glycols, graft polymers of vinyl acetate and / or vinyl propionate on polyethylene glycols, on one or both sides with alkyl , Carboxyl or amino groups end-capped polyethylene glycol le, polydiallyldimethylammonium chlorides and / or polysaccharides such as, in particular, water-soluble starches, starch derivatives and proteins. Such products are described, for example, in Römpp, Chemistry Lexicon 9th Edition, Volume 5, page 3569 or in Houben-Weyl, Methods of Organic Chemistry, 4th Edition, Volume 14/2 Chapter IV Conversion of Cellulose and Starch from E. Husemann and R. Werner, pages 862 - 915 and in Ullmanns Encyklopedia for Industrial Chemistry, 6th edition, volume 28, pages 533 ff under Polysaccharides.

For example, all types of starch are suitable, e.g. both amylose and amylopectin, native starches, hydrophobically or hydrophilically modified starches, anionic starches, cationically modified starches, degraded starches, the starch degradation being able to be carried out, for example, oxidatively, thermally, hydrolytically or enzymatically, and for the starch degradation being both native and modified starches can be used. Other suitable protective colloids are dextrins and cross-linked water-soluble starches that are water-swellable.

Preference is given to using native, water-soluble starches as protective colloids, which can be converted into a water-soluble form, for example with the aid of a starch digestion, and anionically modified starches such as oxidized potato starch. Anionically modified starches which have been subjected to a reduction in molecular weight are particularly preferred. The molecular weight reduction is preferably carried out enzymatically. The average molar mass M _{w of} the degraded starches is, for example, 500 to 100,000, preferably 1000 to 30,000. The degraded starches have, for example, an intrinsic viscosity [η] of 0.04 to 0.5 dl / g. Such starches are described, for example, in EP-B-0257412 and in EP-B-0276770. If protective colloids are used in the polymerization, the amounts used are, for example, 0.5 to 15, in particular 1 to 10,% by weight, based on the monomers used in the polymerization.

In order to modify the properties of the polymers, the polymerization can optionally be carried out in the presence of at least one polymerization regulator. Examples of polymerization regulators are organic compounds which contain sulfur in bound form, such as dodecyl mercaptan, thiodiglycol, ethylthioethanol, di-n-butyl sulfide, di-n-octyl sulfide, diphenyl sulfide, diisopropyl disulfide, 2-mercaptoethanol, 1, 3-mercaptopropanol, 3-mercaptopropane 1, 2-diol, 1, 4-mercaptobutanol, thioglycolic acid, 3-mercaptopropionic acid, mercaptosuccinic acid, thioacetic acid and thiourea, aldehydes such as formaldehyde, acetaldehyde and propionaldehyde, organic acids such as formic acid, sodium formate or ammonium formopropane, alcohols and in particular such as, in particular, alcohols Phosphorus compounds such as sodium hypophosphite. If a regulator is used in the polymerization, the one used in each case is Amount, for example 0.01 to 5, preferably 0.1 to 1 wt .-%, based on the monomers used in the polymerization. Polymerization regulators and crosslinkers can be used together in the polymerization.

The mini emulsion is polymerized in the presence of at least one radical polymerization initiator. All compounds which can trigger a polymerization are suitable as the polymerization initiator. Essentially, these are peroxides, hydroperoxides, azo compounds and redox catalysts. Examples of initiators can be found in WO-A-99/40123, page 32, line 45 to page 34, line 9. The polymerization can also be triggered by exposure to high-energy radiation such as UV radiation. The polymerization temperature is, for example, 0 to 120 ° C., it being carried out at temperatures above 100 ° C. under increased pressure in pressure-tight apparatus. The mini emulsion is usually polymerized in the temperature range from 0 to 95 ° C.

The polymerization is carried out according to the invention in such a way that initially only a maximum of 50% of the monomers which are in the polymerization zone polymerize. The effect substances migrate to the surface of the emulsified particles. There is probably an incompatibility between the effect substances and the developing polymer, or the effect substances are not soluble in the resulting polymer or the mixture of monomer, oligomers and polymers. One only has to give the polymerizing system sufficient time for the effect substances to be separated from the polymer being formed. The polymerization is only completed after the effect substances have largely or completely accumulated on the surface of the polymer particles formed. With the help of sampling during the polymerization, the separation of the effect substance and the polymer being formed can be followed. The effect substances essentially remain on the surface of the polymer particle, but, depending on the polymerization conditions, can also partially enter the aqueous phase, form domains in the polymer particle or otherwise accumulate in the polymer.

For example, a miniemulsion containing at least one effect substance is preferably first prepared

(a) at least one ethylenically unsaturated monomer A with a water solubility of> 0.01 g / l (at 25 ° C and 1 bar), if appropriate

(b) at least one ethylenically unsaturated monomer B with a water solubility of <0.01 g / l (at 25 ° C. and 1 bar) and optionally

(c) at least one ethylenically unsaturated monomer C with at least two double bonds, at least one emulsifier and a hydrophobic organic compound with a water solubility of <0.1 g / l (at 25 ° C. and 1 bar), where the effect substances can also be added to the miniemulsion during or after the emulsification process, the monomers polymerize the miniemulsion then up to a conversion of at most 50%, then metered an aqueous macroemulsion of at least one ethylenically unsaturated monomer C with at least two double bonds in the molecule and leads to the end of the polymerization after the effect substances have largely accumulated on the surface of the resulting polymer particles. If a crosslinking agent is used, it can also be introduced into the miniemulsion together with the monomers (a) and (b), or it can also be emulsified in water and the aqueous

Use the emulsion of the crosslinking agent as a template during the polymerization or dose it batchwise or continuously as an emulsion feed. If at least two crosslinking agents are used, these can be metered in either as a mixture or separately from one another synchronously or with a time delay.

As a rule, up to a maximum of 40% by weight of the miniemulsion is placed in a polymerization zone, the portion of the miniemulsion is then heated to the polymerization temperature and a sufficient amount of polymerization initiator is added to add up to a maximum of 50% of the submitted monomers polymerize, then metered an aqueous macroemulsion of at least one ethylenically unsaturated monomer C with at least two double bonds in the molecule and, after the effect substances have largely accumulated on the surface of the resulting polymer particles, the polymerization is completed by further addition of at least one polymerization initiator.

The miniemulsion containing at least one effect substance is preferably introduced in an amount of at most 30% by weight together with an amount of polymerization initiator which is sufficient to polymerize 5 to 25% of the monomers initially introduced. An embodiment is particularly preferred in which the miniemulsion containing at least one effect substance is introduced in an amount of at most 25% by weight together with an amount of polymerization initiator which is sufficient to polymerize at most 15% of the monomers introduced.

In another embodiment of the invention, a mixture of a miniemulsion of monomers (a) and (b) and a polymerization initiator, which is sufficient for the initiation of a maximum of 25% of the monomers presented, is added to a mixture of a miniemulsion of monomers (a) and (b) and at least one effect substance and heated to the polymerization temperature , the remaining portions of this miniemulsion and an aqueous mixture of a monomer (c) and metered in after the consumption of the added initiator by polymerization further polymerization initiator for the polymerization of the remaining monomers. The preferred monomers are those of the group

(a) methyl methacrylate, styrene, vinyl acetate, methyl acrylate, acrylic acid and / or methacrylic acid, (b) lauryl acrylate, palmityl acrylate and / or stearyl acrylate and

(c) Butanediol diacrylate, divinylbenzene, pentaerythritol triacrylate and / or pentaerythritol tetraacrylate

Aqueous polymer dispersions containing effect substances are obtained in which the effect substances are arranged on the surface of the dispersed polymer particles. The solids concentration of these aqueous dispersions is, for example, 10 to 60, preferably 20 to 45,% by weight. Polymer powders containing effect substances can be obtained from such aqueous dispersions by evaporating the volatile constituents of a polymer dispersion containing aqueous effect substances. In order to obtain pulverulent products, the aqueous dispersions containing effect substances are preferably subjected to spray drying. The dispersions according to the invention and the polymer powders obtained therefrom have the advantage that they contain the effect substances on their surface. The effect substances are therefore in a modification which is particularly advantageous for their application. This fact applies in particular to those polymer powders which have a UV absorber, preferably 4-n-octyloxy-2-hydroxybenzophenone, on their surface.

The aqueous polymer dispersions described above, which contain effect substances on the surface of dispersed polymer particles, are used, for example, to stabilize polymers against the action of UV radiation, oxygen and heat, in cosmetic and pharmaceutical formulations, in lacquer layers, in the production of paper and leather and textiles and used in formulations for animal feeding. Depending on the application, customary additives such as defoamers, thickeners, biocides, buffers, antifreezes, fats and / or oils can be added to the dispersions according to the invention. The application of the dispersions according to the invention is essentially determined by the effect substances contained in the dispersions. For example, aqueous dispersions containing UV absorbers or the powders obtained therefrom are used in cosmetic formulations or for stabilizing polymers, in particular films made of polymers such as polyethylene, polypropylene, polyvinyl chloride, polycarbonate, polyamide or polyester, against the action of UV radiation , The stabilization of films against the influence of UV radiation is particularly important for those films which are used for greenhouses. In addition to the application in the film sector, the Products according to the invention which contain a UV absorber can also be used to stabilize moldings of any shape made from at least one of the abovementioned polymers, in particular polyethylene, polypropylene, acrylonitrile-butadiene-styrene polymers (ABS) and PVC. A concrete example is the use of the products according to the invention for stabilizing PVC profiles for window frames. Aqueous dispersions containing UV absorbers or the polymer powders obtained therefrom can also be used together with other dispersions according to the invention, which contain, for example, stabilizers for polymers such as antioxidants, for stabilizing polymers and lacquer layers.

Aqueous polymer dispersions containing alkenylsuccinic anhydrides, which are obtainable according to the invention, are added to the paper stock as pulp sizing agents in the production of paper. According to the process of the invention, it is also possible to deposit C 1 -C ₄ -alkyl ketene dimers like the other effect substances described above on the surface of polymer particles with an average diameter of <500 nm, which likewise results in aqueous polymer dispersions containing alkyldiketenes, used as bulk sizing agents or surface sizing agents for paper. They are added to the paper stock in the manufacture of paper or applied in a film or size press or in a gate roll.

Examples

The percentages in the examples mean percent by weight. The droplet size of the mini emulsion and the average particle size of the aqueous polymer dispersions prepared by mini emulsion polymerization were determined using a Coulter N4 Plus Particle Analyzer on 0.01% by weight samples of the emulsion.

The mean particle size of the dispersed polymer particles was determined using a Coulter LS 230 on 0.01% by weight samples of the aqueous dispersions.

example 1

Preparation of the UV absorber monomer solution In a mixture of 156.7 g of methyl methacrylate, 11.7 g of stearyl acrylate, 7 g of acrylic acid and 11.7 g of butanediol diacrylate, 46.8 g of the powdery UV absorber 4-n-octyloxy-2 -hydroxy-benzophenone dissolved at room temperature within 15 minutes. Production of the mini emulsion

This solution was then introduced into an aqueous solution of 3.5 g of an aqueous Steinapol NLS solution (15% strength) in 435.8 g of water with stirring. A macroemulsion was obtained, which was then brought to a droplet size of approximately 200 nm by passing three times through an APV-Gaulin high-pressure homogenizer. The mini emulsion thus produced was stable on storage.

miniemulsion

161.5 g (24% of the total amount) of the miniemulsion described above were placed in a reactor and heated to 80 ° C. 0.7 g of a 1% strength aqueous solution of Dissolvine E-Fe13 (iron / salt solution) and 9.35 g of a 2% strength aqueous sodium persulfate solution were then metered in at 80.degree. Thereafter, 511.6 g (76% of the total amount) of the mini-emulsion were metered in, and at the same time 112.2 g of a 2% strength aqueous sodium persulfate solution were added in a separate feed within 60 minutes.

emulsion

Following the mini-emulsion polymerization, an emulsion polymerization was carried out by making a macroemulsion which was stirred and consisting of 58.5 g of methyl methacrylate, 2.3 g of pentaerythritol tetraacrylate and 1.2 g of a 15% strength aqueous sodium lauryl sulfate solution in 30.4 g desalted water was composed, metered into the dispersion obtained by mini-emulsion polymerization within 60 minutes. For the postpolymerization were then added within 60 minutes 112.2 g of a 2% aqueous sodium persulfate solution, the reaction rate followed by stirring for mixing for 60 minutes at 80 ° C, then cooled to 25 ^C C, and filtered it through a 500μm and a 125μm mesh sieve to remove the coagulate (7 g). An aqueous polymer dispersion with an average particle diameter of the polymer particles of 62 nm was obtained. As Elmi photographs of powdery polymer particles which were obtained by drying the aqueous dispersion have shown, the UV absorber enveloped the polymer particles in a shell.

Example 2

Preparation of the UV absorber monomer solution 46.8 g of the powdery UV absorber 4 were added to a mixture of 156.7 g of methyl methacrylate, 11.7 g of stearyl acrylate, 7 g of acrylic acid and 11.7 g of butanediol 1,4-diacrylate - n-Octyloxy-2-hydroxy-benzophenone dissolved at room temperature within 15 minutes. Production of the mini emulsion

This solution was then added with stirring to an aqueous solution of 3.5 g of a 15% aqueous sodium lauryl sulfate solution in 435.8 g of water. A macroemulsion was obtained, which was then brought to a droplet size of 200 nm by passing it three times through an APV-Gaulin high-pressure homogenizer. The mini emulsion thus obtained was stable on storage.

miniemulsion

161.5 g (24% of the total amount) of the mini-emulsion were placed in a reactor and heated to 80.degree. At 80 ° C 0.7 g of a 1% aqueous solution of Dissolvine E-Fe13 (iron II salt solution) and 9.35 g of a 2% aqueous solution of sodium persulfate were added all at once. Then the remaining portion of the mini emulsion of 511.6 g (76% of the total amount) was metered in and, simultaneously, 112.2 g of a 2% aqueous sodium persulfate solution were added in a separate feed, each within 60 minutes.

emulsion

Immediately after the addition of the miniemulsion and the starter solution had ended, a stirred macroemulsion consisting of 58.5 g of methyl methacrylate, 2.3 g of divinylbenzene and 1.2 g of a 15% strength aqueous sodium lauryl sulfate solution in 30 was added to the aqueous dispersion heated to 80.degree , 4 g of completely demineralized water within 60 minutes.

Postpolymerization 112.2 g of a 2% aqueous sodium persulfate solution were then added to the reaction mixture described above within 60 minutes. The reaction mixture was then stirred for a further 60 minutes at 80 ° C., then allowed to cool to 25 ° C. and filtered through a 500 μm and a 125 μm mesh screen in order to remove the coagulum (7 g). An aqueous polymer dispersion with an average particle diameter of the polymer particles of 64 nm was obtained. As Elmi photographs of powdery polymer particles which were obtained by drying the aqueous dispersion have shown, the UV absorber enveloped the polymer particles.

Example 3

Production of the UV absorber monomer solution

47.5 g of the powdery UV absorber 4-n-octyloxy-2-hydroxy-benzophenone were dissolved in a mixture of 225.7 g of methyl methacrylate and 11.9 g of stearyl acrylate within 15 minutes at room temperature. Production of the mini emulsion

This solution was then added to an aqueous solution of 4.8 g of a 15% aqueous sodium lauryl sulfate solution in 626.4 g of water and emulsified. The macroemulsion thus produced was then brought to a droplet size of approximately 200 nm by passing it three times through an APV-Gaulin high-pressure homogenizer. The mini emulsion was stable in storage.

Crosslinking and prepolymerization

219.8 g (24% of the total amount) of the mini emulsion were placed in a reactor and heated to 80.degree. 0.7 g of a 1% strength aqueous solution of Dissolvine E-Fe13 (iron-II-sulfate solution) and 2.9 g of a 5% strength aqueous solution of sodium persulfate were then added at 80 ° C. all at once. Subsequently, 696.3 g (76% of the total amount) of the mini-emulsion was metered in and, at the same time, a stirred mixture (emulsion) of 23.8 g of water and 11.9 g of pentaerythritol tetraacrylate was added in a separate feed over the course of 60 minutes. The reaction mixture was then stirred at 80 ° C. for a further 30 minutes. After this time, only about 10% of the monomers had polymerized.

Polymerization To polymerize the monomers to a large extent, were metered into the heated to 80 ° C the reaction mixture over a period of 60 minutes, 44.6 g of a 5% aqueous solution of sodium persulfate, the mixture followed by stirring for postpolymerization further 60 minutes at 80 ^C C , then allowed to cool to 25 ° C and filtered through a 500 µm and a 125 µm mesh screen to remove the coagulum.

An aqueous polymer dispersion with an average particle diameter of the polymer particles of 61 nm was obtained. As shown by an Elmi uptake of powdery polymer particles, which was obtained by drying the aqueous dispersion, the UV absorber envelops the polymer particles. This can be seen clearly in FIG. 1.

Example 4

Production of the UV absorber monomer solution

46 g of Uvinul 3008 (4-n-octyloxy-2-hydroxy-benzophenone) were dissolved in a mixture of 218.5 g of methyl methacrylate and 11.5 g of decahydronaphthalene within 15 minutes at room temperature.

Production of the mini emulsion

This solution was then introduced into 4.6 g of a 15% aqueous sodium lauryl sulfate solution in 537.62 g of deionized water and emulsified. The mak- roemulsion was then brought to a droplet size of 200 nm by sonication with an ultrasonic finger from Hilscher. This mini emulsion was stable in storage.

Mini emulsion polymerization and emulsion polymerization 196.4 g (24% of the total amount) of the mini emulsion were placed in a reactor and heated to 80 ° C. At 80 ^G C 6.9 g of a 2% aqueous solution of sodium persulfate were then added all at once. Subsequently, 621.9 g (76% of the total amount) of the miniemulsion was metered in and, at the same time, a stirred mixture (emulsion) of 23 g of water, 11.5 g of pentaerythritol tetraacrylate and 1.15 g of a 15% strength aqueous sodium lauryl sulfate solution was added in a separate feed within 60 minutes each. The reaction mixture was then stirred at 80 ° C. for a further 30 minutes. After this time, only about 10% of the monomers were polymerized.

In order to complete the polymerization, 108.1 g of a 2% strength aqueous solution of sodium persulfate were metered into the reaction mixture heated to 80 ° C. over a period of 60 minutes, and the mixture was then stirred at 80 for a further 60 minutes ° C, then allowed to cool to 25 ° C and filtered through a 500 µm and a 125 µm mesh screen to remove the coagulum.

An aqueous polymer dispersion was obtained with an average particle diameter of the polymer particles of 492 nm. As Elmi photographs of powdery polymer particles obtained by drying the aqueous dispersion show, predominantly quite large to 1 μm large, in some cases very irregularly shaped, are found during the drying process agglomerated particles that carry the UV absorber in the shell and are almost empty in the core. Example 5

The aqueous polymer dispersion, which was prepared according to Example 3, was dried to a powder. In a twin-screw extruder, 96.88 parts of polyethylene (Lupolen® 1840 D) were then compounded at 3.12 parts of the powder obtained from the dispersion at a temperature of 200 ° C., and the granules were then processed into a film with a thickness of 100 microns. The zero UV-vis spectrum between 200 and 800 nm was first measured on this film. The film was then weathered according to ISO 4892-2. After the times given in the table, the transmission was measured at Λmax 265 nm. The results are shown in the table. Kneading the aqueous dispersion instead of the powder while evaporating the water gives similarly good results. Comparative Example 1

Example 4 was repeated with the exception that instead of the powder obtained from the aqueous dispersion prepared according to Example 3, 0.5% of the UV absorber 4-n-octyloxy-2-hydroxybenzophenone was now incorporated into polyethylene, made a film out of it, also weathered it according to ISO 4892-2 and examined it for the transmission according to the times given in the table.

table

Sample according to transmission at Λmax 265 nm [%] after loss of absorption at 0 1000h 2000h 3000h 4000h 265 nm [%] after 2000h

Example 5 32 34 34 38 47 1, 5

Comparative Example 1 32 43 75 68 Foil 63 was destroyed

Claims

claims

1. Aqueous polymer dispersions containing effect substances with an average particle diameter of the dispersed particles of <500 nm, the polymer particles containing as a core a polymer matrix composed of at least one ethylenically unsaturated monomer, on the surface of which at least partially an effect substance is arranged, which is arranged in the Soluble monomers that form the polymer matrix of the particles.

2. Aqueous polymer dispersions containing effect substances according to claim 1, characterized in that the effect substances are arranged as a shell around the core of the polymer particles.

3. Aqueous polymer dispersions containing effect substances according to claim 1 or 2, characterized in that the amount of the effect substances is 0.5 to 50% by weight, based on the polymer matrix.

4. Aqueous polymer dispersions containing effect substances according to claim 1 to 3, characterized in that the effect substances are selected from the group of UV absorbers, organic dyes, optical brighteners, stabilizers and auxiliaries for organic polymers, IR dyes, flame retardants, alkenyl succinic anhydrides, active pharmaceutical ingredients and biocides.

5. Aqueous polymer dispersions containing effect substances according to one of claims 1 to 4, characterized in that the core of the dispersed particles consists essentially of a polymer

(a) at least one ethylenically unsaturated monomer A with a water solubility of> 0.01 g / l (at 25 ° C. and 1 bar), optionally (b) at least one ethylenically unsaturated monomer B with a water solubility of <0.01 g / l (at 25 ° C. and 1 bar) and optionally (c) at least one ethylenically unsaturated monomer with at least two double bonds.

6. Aqueous polymer dispersions containing effect substances according to one of claims 1 to 5, characterized in that the dispersed polymer particles (a) 50 to 99.5% by weight of at least one monomer A, (b) 0.5 to 50% by weight. at least one monomer B and (c) 0 to 30% by weight of at least one monomer C. contained in polymerized form.

7. Aqueous polymer dispersions containing effect substances according to claims 1 to 6, characterized in that the dispersed polymer particles consist of a polymer

(a) methyl methacrylate, styrene, vinyl acetate, methyl acrylate, ethyl methacrylate, acrylic acid and / or methacrylic acid, optionally (b) lauryl acrylate, palmitylacrylate and / or stearyl acrylate and optionally (c) butanediol diacrylate, divinylbenzene, pentaerythritol triacrylate and / or.

8. Aqueous polymer dispersions containing effect substances according to claims 1 to 7, characterized in that the dispersed polymer particles from a polymer of (a) methyl methacrylate, ethyl methacrylate and / or acrylic acid, optionally (b) stearyl acrylate and / or palmitylacrylate and (c) butanediol diacrylate, Pentaerythritol tetraacrylate and / or pentaerythritol triacrylate are constructed.

9. Aqueous polymer dispersions containing UV absorbers as effect substances according to claims 1 to 6, characterized in that the dispersed polymer particles from a polymer of (a) methyl methacrylate or methyl methacrylate and acrylic acid, (b) stearyl acrylate and (c) butanediol diacrylate, pentaerythritol tetraacrylate and / or pentaerythritol triacrylate and are coated with a shell from the UV absorber 4-n-octyloxy-2-hydroxybenzophenone.

10. A process for the preparation of aqueous polymer dispersions containing effect substances with an average particle diameter of the dispersed polymer particles of <500 nm by miniemulsion polymerization of ethylenically unsaturated monomers, characterized in that by emulsifying ethylenically unsaturated monomers in water in the presence of at least one effect substance and one a mini emulsion with a surfactant produces average particle size of the emulsified droplets of <500 nm, and polymerizes them in the presence of at least one radical polymerization initiator in such a way that initially only a maximum of 50% of the monomers which are in the polymerization zone polymerize and the effect substances migrate to the surface of the emulsified particles, and the polymerization only comes to an end after the effect substances have largely or completely accumulated on the surface of the resulting polymer particles.

11. The method according to claim 10, characterized in that first a miniemulsion of the monomers

(a) at least one ethylenically unsaturated monomer A with a water solubility of> 0.01 g / l (at 25 ° C and 1 bar), optionally (b) at least one ethylenically unsaturated monomer B with a water solubility of <0.01 g / l (at 25 ° C and 1 bar) and optionally (c) at least one ethylenically unsaturated monomer C with at least two double bonds which contain at least one effect substance, at least one emulsifier and at least one hydrophobic organic compound with a water solubility of <0.1 g / l (at 25 ° C and 1 bar), then polymerizes the monomers of the miniemulsion up to a conversion of at most 50%, then adds an aqueous macroemulsion of at least one ethylenically unsaturated monomer C with at least two double bonds in the molecule and the polymer on to the end after extensive accumulation of the effect substances on the surface of the resulting polymer particles.

12. The method according to claim 10 or 11, characterized in that up to a maximum of 40% by weight of the miniemulsion is placed in a polymerization zone, the portion of the miniemulsion is then heated to the polymerization temperature and a sufficient amount of polymerization initiator is added, in order to polymerize a maximum of 50% of the monomers initially introduced, then add an aqueous macroemulsion of at least one ethylenically unsaturated monomer C with at least two double bonds in the molecule and, after the effect substances have largely accumulated on the surface of the resulting polymer particles, the polymerization is completed by further addition of at least one polymerization initiator ,

13. The method according to claim 12, characterized in that the miniemulsion is introduced in an amount of at most 30% by weight together with such an amount of polymerization initiator that is sufficient to polymerize 5 to 25% of the monomers introduced.

14. The method according to claim 12 or 13, characterized in that the miniemulsion is introduced in an amount of at most 25% by weight together with such an amount of polymerization initiator that is sufficient to polymerize at most 15% of the monomers introduced.

15. The method according to any one of claims 12 to 14, characterized in that to a mixture heated to the polymerization temperature from a submitted, at least one effect substance-containing miniemulsion of the monomers (a) and optionally (b) and polymerization initiator for Initiation of a maximum of 25% of the monomers submitted is sufficient, the remaining portions of this miniemulsion and an aqueous mixture of a monomer (c) are added and, after the initiator has been consumed, polymerization is used to polymerize the remaining monomers by polymerization.

16. The method according to claims 12 to 15, characterized in that to a heated to the polymerization temperature mixture of a submitted, at least one effect substance-containing miniemulsion of the monomers (a) and optionally (b) and polymerization initiator, which is used for the initiation sufficient of a maximum of 15% of the monomers initially introduced, add the remaining portions of this mini emulsion and an aqueous macroemulsion of a monomer (c) and, after the initiator used has been consumed, add further polymerization initiator by polymerization to polymerize the remaining monomers.

17. The method according to any one of claims 10 to 16, characterized in that the monomers of group (a) methyl methacrylate, styrene, vinyl acetate, methyl acrylate, acrylic acid and / or methacrylic acid, (b) lauryl acrylate, palmitylacrylate and / or stearyl acrylate and (c ) Uses butanediol diacrylate, divinylbenzene, pentaerythritol triacrylate and / or pentaerythritol tetraacrylate.

18. Polymer powders containing effect substances, obtainable by evaporating the volatile constituents of a polymer dispersion containing aqueous effect substances according to claims 1 to 9.

19. Polymer powders containing effect substances according to claim 18, characterized in that they contain a UV absorber, preferably 4-n-octyloxy-2-hydroxy-benzophenone, as the effect substance.

20. Use of polymer powder containing effect substances according to claim 18 or 19 for stabilizing polymers against the action of UV radiation, oxygen and heat, in cosmetic and pharmaceutical formulations, in lacquer layers, in the production of paper, leather or textiles and in formulations for animal nutrition.