EP1999163A1 - Polymer dispersions comprising effect substances and use thereof - Google Patents

Abstract

Aqueous polymer dispersions whose dispersed particles comprise at least one effect substance from the group of UV absorbers, antistats, antioxidants and antifogging agents, have a mean particle size of at most 500 nm and a glass transition temperature of at least 85°C and which are obtainable by emulsion polymerization of ethylenically unsaturated monomers in the presence of at least one effect substance and the use of the polymer dispersions comprising effect substances or of the polymer powders obtained therefrom for modifying and for stabilizing polymers, especially for stabilizing thermoplastic polymers against the action of UV radiation.

Description

Effect dispersions containing polymer dispersions and their use

description

The invention relates to aqueous polymer dispersions whose dispersed particles contain at least one effect substance from the group of UV absorbers, antistatic agents, antioxidants and antifogging agents, have an average particle size of at most 500 nm and which are obtainable by emulsion polymerization of ethylenically unsaturated monomers in the presence of at least one of Effect substances and the use of the polymer dispersions containing polymer blends or the polymer powders obtained therefrom for equipping and / or stabilizing thermoplastic polymers, in particular for stabilizing against the action of UV radiation.

For the protection of materials such as polymers against the action of UV rays, z. B. so-called UV absorber. In the application of UV absorbers, it is necessary to distribute a small amount of the active ingredient in a large amount of a polymer or on a large area of a substance as evenly as possible. The UV absorbers are lipophilic and therefore practically insoluble in water. As a rule, less than 5 g / l of the active ingredient dissolve at 23 ° C. and 1013 mbar. However, to apply them according to the desired purpose, they must be in finely divided form. There are different methods for this.

By way of example, UV absorbers are incorporated into a polymer by melting it and mixing the melt under the action of shearing forces with a formulation containing the UV absorber. For example, it is possible to use a dilute aqueous polymer dispersion for this purpose, the polymers of which contain a UV absorber. The dispersions are usually diluted with water to the respective application concentration shortly before use. The dispersions always contain a dispersion stabilizer which stabilizes the inherently metastable systems. Aqueous polymer dispersions whose dispersed particles contain a UV absorber can be prepared, for example, by two different polymerization processes, namely by the process of emulsion polymerization or miniemulsion polymerization.

So z. For example, JP-A 7-292009 discloses aqueous polymer dispersions which contain functional substances, 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 form a monomer emulsion with average particle sizes between 5 and 500 nm and polymerizing the miniemulsion in the presence of a free-radical initiator. The aqueous dispersions containing the functional substances such as UV absorbers, epoxy resins, acrylic-based polymers, phenolic resins, unsaturated polyesters, substances based on phenol and petroleum resins are used as a binder and as an additive for protective film.

WO 99/40123 discloses a process for the preparation of aqueous polymer dispersions whose dispersed polymer particles are homogeneous, ie. H. distributed molecularly dispersed. Such aqueous dispersions are prepared by miniemulsion polymerization by polymerizing ethylenically unsaturated monomers which contain an organic dye dissolved in the form of an oil-in-water emulsion in the presence of radical-forming polymerization initiators, the disperse phase of the miniemulsion essentially being colored 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 sedimentation-stable. The dispersed particles have a mean 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 US 3,400,093 a method for producing a polymer latex-containing ^{insecticides'} or polymer is known, said emulsifying a solution of a substantially water-insoluble insecticide in at least one vinyl monomer in an aqueous solution containing at least one surfactant, and this mixture is then subjected to the emulsion polymerization.

According to the process known from EP-A 875 544, it is possible, for example, to prepare UV absorber-containing polymer dispersions by dissolving at least one UV absorber in at least one ethylenically unsaturated monomer and subsequently subjecting the solution to an emulsion polymerization in water comprising a polymerization initiator and contains an emulsifier. The polymer particles may be composed of a single polymer or have a core / shell structure, where the UV absorber may be either in the core or in the shell of the polymer particle or both in the core and in the shell. The glass transition temperature of the fine-particle polymers is preferably 30 ° C. or below.

WO 01/10936 discloses particles with a core / shell structure in which the core comprises a polymer having a glass transition temperature T ₉ of below 40 ° C. and a polymerized UV absorber. The monomer composition which constitutes the core consists essentially of ethyl acrylate, optionally one

(Meth) acrylate function-containing UV absorber and optionally a crosslinking agent. zer. The shell is preferably made of a polymer of ethyl acrylate and / or methyl methacrylate. The polymer particles containing a UV absorber are prepared by two-stage emulsion polymerization. They have an average particle diameter of 40 to 200 nm and are used to make UV-absorbing polymer compositions.

From DE-A 102 54 548 the use of finely divided, at least one UV absorber-containing polymer powder for the stabilization of polymers against the action of UV radiation is known. The polymer particles of the polymer powders have a particle size of 500 nm or below. They are prepared by miniemulsion polymerization according to methods known from the above-mentioned WO 99/40123. The polymer particles contain 0.5 to 50 wt .-% of at least one UV absorber, which is present either homogeneously distributed in molecular or nanocrystalline form or completely or even partially surrounded by the polymer matrix.

WO 05/087816 discloses aqueous polymer dispersions containing effect substances having an average particle diameter of the dispersed particles of <500 nm, the polymer particles containing a polymer matrix composed of at least one ethylenically unsaturated monomer as the core, on the surface of which at least partially arranged an effect substance which is soluble in the monomers which form the polymer matrix of the particles. These polymer dispersions are prepared by emulsifying a solution of an effect substance in at least one ethylenically unsaturated monomer in the presence of at least one surface-active agent in water to give a miniemulsion and polymerizing the monomers in the presence of a free-radical polymerization initiator in such a way that initially only a maximum of 50% of the monomers polymerize. which are in the polymerization zone and wherein the effect substances migrate to the surface of the emulsified particles, and the polymerization only after extensive or complete accumulation of the effect substances on the surface of the resulting polymer particles to an end. Following the miniemulsion polymerization, a customary emulsion polymerization of neutral ethylenically unsaturated monomers takes place in the dispersion obtained by miniemulsion polymerization. Suitable effect substances are, for example, UV absorbers, stabilizers for organic polymers, organic dyes, flameproofing agents, alkenylsuccinic anhydrides, alkyldiketenes, active pharmaceutical ingredients, biocides and optical brighteners.

WO 2006/015791 discloses a process for preparing aqueous active substance compositions of active substances which are sparingly soluble in water. The method comprises the following steps: a) providing an aqueous suspension of solid drug particles of at least one active ingredient having a water solubility of not more than 5 g / l at

25 ° C / 1013 mbar, containing at least one surface-active substance for stabilizing the dispersed active ingredient particles, wherein the active substance particles in the suspension have an average particle size, determined by dynamic light scattering, of not more than 1200 nm,

b) emulsion polymerization of a first monomer composition M1 in the aqueous suspension of the active ingredient, wherein the monomer composition M1 contains at least 95% by weight, based on its total weight, of at least one neutral, monoethylenically unsaturated monomer M1.1 having a water solubility of not more than 30 g / l at 25 ° C / 1013 mbar to obtain an aqueous dispersion of polymer-drug particles, and

c) emulsion polymerization of a second monomer composition M2 in an aqueous dispersion of the polymer active agent particles obtained in step b), wherein the monomer composition M2 at least 60 wt .-%, based on their total weight, of at least one neutral, monoethylenically unsaturated monomer M2.1 having a water solubility of not more than 30 g / l at 25 ° C / 1013 mbar.

In this context, active ingredients are understood to be substances which already cause a physiological reaction in a low concentration in an organism. Preferably, they are active ingredients for crop protection and for the protection of material, for. For example, herbicides, fungicides, insecticides, acaricides, nematicides, bactericides, growth regulators and other biocides.

The object of the invention is to provide further dispersions containing water-insoluble effect substances.

The object is achieved according to the invention with aqueous polymer dispersions whose dispersed particles contain at least one effect substance from the group of UV absorbers, antistatic agents, antioxidants and antifogging agents, have an average particle size of at most 500 nm and which are obtainable by emulsion polymerization of ethylenically unsaturated monomers in the presence of at least one effect substance, when the matrix polymers of the dispersed particles have a glass transition temperature of at least 85 ° C.

The dispersed polymer particles may be single particles or preferably those having a core / shell structure, and wherein the matrix polymers have a glass transition temperature T ₉ of at least 95 ° C and at least one effect substance, preferably a non-polymerizable UV absorber, in the core, in the shell or in the core and in the shell. The particles may also contain several shells, for example 2 to 5 shells. Particular preference is given to dispersed polymer particles which have a core / shell structure and contain at least one UV absorber in the polymer matrix of the core. The polymer matrix of the dispersed discrete particles of the dispersion and the polymer matrix forming the core of the core / shell polymer particles is preferably crosslinked.

The crosslinked polymer is preferably from at least one monomer of the group

(i) Cr to Cio-alkyl acrylates, C 1 to C 10 -alkyl methacrylates, styrene, acrylonitrile and methacrylonitrile and

(Ii) at least one crosslinker from the group taerythrittriacrylat allyl acrylate, Allyllmethacrylat, Pen, pentaerythritol tetraacrylate, pentaerythritol trimethacrylate, pentaerythritol rythrittetramethacrylat, ethylene glycol diacrylate, ethylene glycol dimethacrylate, tandioldiacrylat Bu, butanediol dimethacrylate, trimethylolpropane triacrylate, trimethylolpropane lolpropantrimethacrylat, butadiene, divinyl benzene, methylene bisacrylamide and divinylurea

built up.

The eligible effect substances are usually used in unmodified form as an additive to organic polymers to equip the polymers, for example, antistatic or fogging or to stabilize them against oxidation, exposure to UV rays, heat and / or light. Such stabilizers are commercial products. For example, UV absorbers are sold under the trademark Uvinul® by BASF Aktiengesellschaft, Ludwigshafen. The suitable UV absorbers have, for example, a water solubility of at most 5 g / l (determined at 25 ° C. and 1013 mbar) and are soluble in the monomers which form polymers having a glass transition temperature of at least 85 ° C.

Under UV absorbers are known to UV-absorbing compounds that disable the absorbed radiation without radiation. UV absorbers absorb light of wavelength <400 nm and convert it into heat radiation. Such compounds are used for example in sunscreens and for the stabilization of organic polymers. Examples of UV absorbers are derivatives of p-aminobenzoic acid, in particular their esters z. Ethyl 4-aminobenzoate and ethoxylated 4-aminobenzoic acid ethyl esters, salicylates, substituted cinnamates (cinnamates) such as octyl-p-methoxycinnamate or 4-isopentyl-4- methoxycinnamate, 2-phenylbenzimidazole-5-sulfonic acid and its salts. A particularly preferred UV absorber is 4-n-octyloxy-2-hydroxybenzophenone. Further examples of UV absorbers are:

Substituted acrylates, such as. As ethyl or isooctyl-α-cyano-ß, ß-diphenylacrylate

(mainly 2-ethylhexyl-α-cyano-β, β-diphenylacrylate), methyl-α-methoxycarbonyl-β-phenylacrylate, methyl-α-methoxycarbonyl-β- (p-methoxyphenyl) acrylate, methyl or butyl-α-cyano β-methyl-β- (p-methoxyphenyl) acrylate, N- (β-methoxycarbonyl-β-cyanovinyl) -2-methylindoline, octyl-p-methoxycinnamate, isopentyl-4-methoxycinnamate, urocanic acid and its salts and esters;

2-Hydroxybenzophenone derivatives, such as. 4-hydroxy, 4-methoxy, 4-octyloxy, 4-decyloxy, 4-dodecyloxy, 4-benzyloxy, 4, 2 ', 4'-trihydroxy, 2'-hydroxy-4, 4'-dimethoxy-2-hydroxybenzophenone and 4-methoxy-2-hydroxybenzophenone sulfonic acid sodium salt;

Esters of 4,4-diphenylbutadiene-1, 1-dicarboxylic acid, such as. The bis (2-ethylhexyl) ester;

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

Derivatives of benzoxazoles;

Derivatives of benzotriazoles and 2- (2'-hydroxyphenyl) benzotriazoles, such as. B. 2- (2H-Benztriazol-2-yl) -4-methyl-6- (2-methyl-3- ((1,1,3,3-tetramethyl-1- (trimethylsilyloxy) disiloxanyl) -propyl) - phenol, 2- (2'-hydroxy-5'-methylphenyl) benztriazole, 2- (3 ', 5'-di-tert-butyl-2'-hydroxyphenyl) benztriazole, 2- (5'-tert-butyl) 2'-hydroxyphenyl) benztriazole, 2- [2'-hydroxy-5 '- (1,1,3,3-tetramethylbutyl) phenyl] benztriazole, 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 tert-butyl-2'-hydroxyphenyl) benzotriazole, 2- (2'-hydroxy-4'-octyloxyphenyl) benzotriazole, 2- (3 ', 5'-di-tert-amyl-2'-hydroxyphenyl) benztriazole, 2- [3 ', 5'-bis (α, α-dimethylbenzyl) -2'-hydroxyphenyl] benzotriazole, 2- [3'-tert-butyl-2'-hydroxy-5' - (2-octyloxycarbonylethoxy) phenyl - δ-chlorobenzotriazole, 2- [3'-tert-butyl-5 '- (2- (2-ethylhexyloxy) -carbonylethyl) -2'-hydroxyphenyl] -5-chlorobenzotriazole, 2 [3'-tert-butyl- 2'-hydroxy-5 '- (2-methoxycarbonylethyl) phenyl] -5-chlorobenzotriazole, 2- [3'-tert-butyl-2'-hydroxy-5' - (2-methoxycarbonylethyl) phenyl] benztriazole, 2- [3'-tert-butyl-2'-hydroxy-5'- (2-octyloxycarbonylethyl) phenyl] benztriazole, 2- [3'-tert-butyl-5 '- (2- (2-ethylhexyloxy) carbonylethyl) -2'-hydroxyphenyl] benztriazole, 2- (3'-dodecyl-2'-hydroxy-5'-methylphenyl) benztriazole, 2- [3'-tert-butyl -2'-hydroxy-5 '- (2-isooctyloxycarbonylethyl) phenyl] benzotriazole, 2,2'-methylene-bis [4- (1,1,3,3-) tetramethylbutyl) -6-benztriazol-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-benztriazol-2-ylphenyl, 2- [2 ' -Hydroxy-3 '- (α, α-dimethylbenzyl) -5' - (1,1,3,3-tetramethylbutyl) phenyl] benztriazole, 2- [2'-hydroxy-3 '- (1, 1, 3, 3-tetramethylbutyl) -5 '- (α, α-dimethylbenzyl) phenyl] benzotriazole;

Benzylidene camphor and its derivatives, as described, for. B. in DE-A 38 36 630 are called, for. 3-benzylidene camphor, 3 (4'-methylbenzylidene) d-1-camphor;

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

Dibenzoylmethane, such as. For example, 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- ((tertiary

Butyl) aminocarbonyl) phenylamino) -1, 3,5-triazine-2,4-diyl) imino) bis (benzoic acid 2'-ethylhexyl ester); and

2- (2-hydroxyphenyl) -1, 3,5-triazines, such as. B. 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-triazine, 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-diphenyl -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 the document 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. Preferably, non-polymerizable UV absorbers are used. However, it is also possible to use UV absorbers which have, for example, an acrylic or methacrylic group. Such UV absorbers can be polymerized. Examples of this can be found in the abovementioned EP-A 875 544, pages 10 to 16, line 47, and WO 01/10936.

In addition, stabilizers and auxiliaries for organic polymers, in particular thermoplastic polymers, come into consideration as effect substances. The stabilizers are compounds that stabilize polymers against degradation upon exposure to oxygen, light or heat. They are also referred to as antioxidants or as UV and light stabilizers, cf. Ullmanns, Encyclopedia of Industrial Chemistry, Vol. 3, 629-650 (ISBN-3-527-30385-5) and EP-A 1 1 10 999, page 2, line 29 to page 38, line 29. With such stabilizers virtually all organic polymers are stabilized, cf. EP-A 1 110 999, page 38, line 30 to page 41, line 35. These references are incorporated by reference into the disclosure 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, see Römpp, 10th edition, volume 5, pages 4206 - 4207).

Examples of auxiliaries for polymers are substances which at least largely prevent the fogging of films and molded parts made of plastics, so-called antifogging agents. Commercial stabilizers and adjuvants are sold under the Tinuvin® and Cyasorb® trademarks of Ciba and Tenox® by Eastman Kodak. Stabilizers and auxiliaries are described for example in Plastics Additives Handbook, 5th edition, Hanser Verlag, 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 25 ° C. and a pressure of 1013 mbar.

The aqueous polymer dispersions whose dispersed particles contain at least one effect substance from the group of UV absorbers, antistatic agents, antioxidants and anti-fogging agents and have an average particle size of at most 500 nm are by emulsion polymerization of ethylenically unsaturated monomers in the presence of at least one UV absorber obtainable by that one

(a) at least one effect substance from the group of UV absorbers, antistatic agents, antioxidants and antifogging agents, having a water solubility of not more than 5 g / l (determined at 25 ° C and 1013 mbar) dissolved in a monomer composition forming polymers having a T ₉ of at least 85 ° C, and

(b) subjecting the monomer solution prepared in step (a) to emulsion polymerization in the presence of a dispersion stabilizer.

The particle size of the dispersed particles is below 500 nm, for example in the range of 50 to 300 nm, preferably 80 to 250 nm. They have a glass transition temperature of at least 85 ° C. According to Fox (TG Fox, Bull. Am. Phys Soc. (Ser. II) 1, 123 [1956] and Ullmann's Encyclopedia of Industrial Chemistry, Weinheim (1980), pp 17-18) applies to the glass transition temperature of not or weakly cross-linked copolymers at high molecular weights in a good approximation

1 X ¹ X ² Xπ

T _n J 1 T 2 T n

where X ¹ , X ² X ⁿ mean the mass fractions of the monomers 1, 2 n and T ₉ ¹ , T ₉ ² T _g ⁿ the glass transition temperatures of each of only one of the monomers 1, 2 n constructed polymers in degrees Kelvin. The latter are z. For example, Ullmann's Encyclopedia of Industrial Chemistry, VCH, Weinheim, Vol. A 21 (1992) p. 169, or J. Brandrup, EH Immergut, Polymer Handbook 3rd Ed., J. Wiley, New York 1989.

Incidentally, the glass transition temperature T ₉ is understood to be the midpoint temperature determined by differential thermal analysis (DSC) according to ASTM D 3418-82 (see Ullmann's Encyclopedia of Industrial Chemistry, 5th Edition, Volume A 21, VCH Weinheim 1992, p Zosel, color and paint 82 (1976), pp. 125-134, see also DIN 53765).

Polymer particles with core / shell structure are accessible, for example, by

(a) at least one effect substance from the group of UV absorbers, antistatic agents, antioxidants and antifogging agent which has a water solubility of at most 5 g / l (determined at 25 ° C. and 1013 mbar) in a monomer composition, forming the polymers having a T ₉ of at least 85 ° C,

(b) subjecting the monomer solution prepared in step (a) to emulsion polymerization in the presence of a dispersion stabilizer and then (C) in the polymer dispersion obtained in step (b), a monomer composition which forms polymers having a glass transition temperature of at least 85 ^° C. is subjected to at least one emulsion polymerization in the presence of a dispersion stabilizer.

The aqueous dispersions thus prepared contain particles having a core / shell structure, wherein only the core contains at least one effect substance from the group of UV absorbers, antistatic agents, antioxidants and antifogging agents, preferably a UV absorber. However, it is also possible to prepare dispersions whose dispersed particles contain at least one of the said effect substances both in the core and in the shell. Such aqueous dispersions are accessible by

(a) at least one effect substance from the group of UV absorbers, antistatic agents, antioxidants and antifogging agent which has a water solubility of at most 5 g / l (determined at 25 ° C. and 1013 mbar) in a monomer composition, which forms a polymer matrix having a T ₉ of at least 85 ° C,

(b) subjecting the monomer solution prepared in step (a) to emulsion polymerization in the presence of a dispersion stabilizer and then

(C) in the polymer dispersion obtained in step (b) a monomer composition which forms a polymer matrix having a glass transition temperature of at least 85 ° C, in the presence of a dispersion stabilizer and at least one effect substance of at least one emulsion polymerisation.

In a single emulsion polymerization step according to (c), particles consisting of a core and a single shell are obtained. If a plurality of emulsion polymerizations with different monomer compositions is carried out successively, particles having core / shell structures which have a plurality of shells, for example 2, 3, 4 or even 5 shells, are obtained.

These dispersions may contain particles having a core / shell structure which have the same effect substance in the same or in different concentrations both in the polymer matrix of the core and in the shell or which contain a different effect substance in the polymer matrix of the core than in the shell , Preferably used effect substances are UV absorbers.

In addition, it is possible to prepare dispersions whose dispersed particles have such a core / shell structure which contains at least one effect substance only in the shell. Such dispersions are accessible by that (a) subjecting a monomer composition forming a polymer matrix having a glass transition temperature of at least 85 ° C to emulsion polymerization in the presence of a dispersion stabilizer, and then

(B) in the dispersion obtained after step (a), a solution of at least one effect substance from the group of UV absorbers, antistatic agents, antioxidants and anti-fogging agent in a monomer composition forming matrix polymers having a glass transition temperature of at least 85 ° C, in the presence a dispersion stabilizer subjected to at least one emulsion polymerization.

After the core of the polymer has been formed, at least one shell is polymerized thereon by conducting an emulsion polymerization. Here, too, a single emulsion polymerization or successively several emulsion polymerizations, for. B. 2, 3. 4 or 5 Polymerisationsschritte with different monomer compositions or different solutions of effect substances in the monomer make. This gives polymer particles with a core / shell structure, the particles containing at least one shell, but also several shells, for. B. 2, 3, 4 or 5 shells.

The monomer composition which is subjected to each of the emulsion polymerization is selected such that it results in matrix polymers that have a glass transition temperature of at least 85 ° C, preferably of at least 92 ⁰ C. This requirement applies to both dispersed particles composed of a single monomer composition and particles having a core / shell structure. Suitable monomer compositions consist of either a single monomer or mixtures of two or more monomers. For example, they may consist of at least one monomer of group (i). For example, this group includes

(i) esters of ethylenically unsaturated C 3 -C 5 -carboxylic acids and alcohols having 1 to 10 C atoms in the molecule, in particular C 1 -C 10 -alkyl acrylates and C 1 -C 10 -alkyl methacrylates, styrene, 2-methylstyrene, 4-methylstyrene, p-tert-butylstyrene, acrylonitrile and methacrylonitrile.

Preferred monomers of group (i) are methyl methacrylate, methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, sec-butyl acrylate, isobutyl acrylate, tert-butyl acrylate, 2-ethylhexyl acrylate, ethyl heptyl acrylate, ethyl methacrylate, propyl methacrylates, n-butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate and 2-ethylhexyl methacrylate. Particular preference is given to using, as monomer composition of group (i), methyl methacrylate, styrene and tert-butyl acrylate.

Preferred aqueous polymer dispersions containing at least one effect substance from the group of UV absorbers, antistatic agents, antioxidants and antifogging agents comprise crosslinked polymer particles. Such dispersions can be prepared, for example, by polymerizing at least one monomer of group (i) with at least one crosslinker. Crosslinkers are known to be polymerizable compounds containing at least two ethylenically unsaturated double bonds. Examples of crosslinkers can be found in WO 99/40123, page 8, line 22 to page 9, line 39.

Preferably, crosslinkers are used which belong to the following group (ii) of the

Monomer composition, namely

(ii) allyl acrylate, allyl methacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate,

Pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, ethylene glycol diacrylate, ethylene glycol dimethacrylate, butanediol diacrylate, butanediol dimethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, butadiene, divinylbenzene, di-vinyl urea and methylenebisacrylamide. Also suitable are crosslinkers sold by Sartomer under the following names: CN435, SR454, SR499, SR502, SR593, SR415, SR9019, SR351M, SR9021, SR9020, SR492, SR368, SR355, SR399, SR494 and SR399 LV.

Further preferred monomer compositions are combinations of

(i) methyl methacrylate, styrene and / or tert-butyl acrylate and

(ii) allyl acrylate, allyl methacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, trimethylolpropane triacylate and / or trimethylolpropane trimethacrylate.

Optionally, the polymers may be modified by employing another group (iii) of monomers in the polymerization. This group of monomers are, for example, monoethylenically unsaturated monomers other than the monomers of group (i), such as vinyl acetate, vinyl propionate, N-vinylformamide, acrylamide, methacrylamide, N-vinylimidazole, acrylic acid, methacrylic acid , Maleic acid, crotonic acid, itaconic acid, acrylamidomethylpropanesulfonic acid, vinylsulfonic acid, N-vinylpyrrolidone, N-vinylcaprolactam, glycidyl methacrylate, N-methylolacrylamide, 2-hydroxyethyl acrylate, 3-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 2-dimethyminoethyl acrylate as free base, as salt or in quaternized form , Dimethy aminoethyl methacrylate as free base, as salt or in quaternized form, diacetonacylamide, ureidomethacrylate and vinylphosphonic acid. These monomers are used alone or in combination with one another in the preparation of the aqueous dispersions of the monomers of group (i) and optionally (ii). The amounts of monomers of group (iii) in the monomer composition are adjusted so that dispersions arise and that the glass transition temperature of the resulting polymer matrix is at least 85 ° C.

The polymerization of the monomers takes place by the method of emulsion polymerization, i. the monomers to be polymerized are present in the polymerization mixture as an aqueous emulsion which is stabilized with at least one dispersion stabilizer (emulsifier). For this purpose, the monomers can be added in bulk or in the form of a solution containing the effect substance, preferably a UV absorber. The monomers can be initially charged in the reactor prior to the start of the polymerization or added under polymerization conditions in one or more portions or continuously, and always - as usual in emulsion polymerization - a dispersion stabilizer must be present. If crosslinked polymers are prepared, it is possible to proceed, for example, by metering at least one crosslinker continuously into the reaction zone, either separately from the other monomers or in mixture with the other monomers. Another variant is to gradually add the crosslinker to the reaction zone.

The monomers are preferably used in an amount such that the weight ratio of effect substance to monomers is in the range from 10: 1 to 1:50, in particular from 5: 1 to 1:30 and particularly preferably in the range from 2: 1 to 1:20.

The starters which are suitable for the emulsion polymerization are, in principle, all polymerization initiators which are suitable and usually used for emulsion polymerization and which initiate a free-radical polymerization of ethylenically unsaturated monomers. These include, for example, azo compounds such as 2,2'-azobisisobutyronitrile, 2,2'-azobis (2-methylbutyronitrile), 2,2'-azobis [2-methyl-N - (2-hydroxyethyl) propionamide, 1,1 'Azobis (1-cyclohexanecarbonitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (N, N'-dimethyleneisobutyroamidine) dihydrochloride, and 2,2'-azobis (2-amidinopropane ) dihydrochloride, organic or inorganic peroxides such as diacetyl peroxide, di-tert-butyl peroxide, diamyl peroxide, dioctanoyl peroxide, didecanoyl peroxide, dilauroyl peroxide, dibenzoyl peroxide, bis (o-toluyl) peroxide, succinyl peroxide, tert-butyl peracetate, tert-butyl permalate, tert Butyl perisobutyrate, tert-butyl perpivalate, tert-butyl peroctoate, tert-Butylperneodecanoat, tert-butyl perbenzoate, tert-butyl peroxide, tert-butyl hydroperoxide, cumene hydroperoxide, tert-butyl peroxy-2-ethylhexanoate and Diisopropylperoxidicarbamat, salts of peroxydisulfuric and redox initiator systems. For the polymerization, preference is given to using a redox initiator system, in particular a redox initiator system which contains as the oxidizing agent a salt of peroxodisulfuric acid, hydrogen peroxide or an organic peroxide such as tert-butyl hydroperoxide. As the reducing agent, the redox initiator systems preferably contain a sulfur compound, which is especially selected from sodium hydrogen sulfite, sodium hydroxymethanesulfinate and the bisulfite adduct of acetone. Further suitable reducing agents are phosphorus-containing compounds such as phosphorous acid, hypophosphites and phosphinates, as well as hydrazine or hydrazine hydrate and ascorbic acid. Furthermore, redox initiator systems may contain an addition of small amounts of redox metal salts, such as iron salts, vanadium salts, copper salts, chromium salts or manganese salts, for example the redox initiator system ascorbic acid / iron (II) sulfate / sodium peroxodisulfate. Particularly preferred redox initiator systems are acetone bisulfite adduct / organic hydroperoxide such as tert-butyl hydroperoxide, sodium disulfite (Na 2 SO 2) / organic hydroperoxide such as tert-butyl hydroperoxide, sodium hydroxymethanesulfinate / organic hydroperoxide such as tert-butyl hydroperoxide and ascorbic acid / hydrogen peroxide.

The initiator is usually employed in an amount of 0.02 to 2% by weight and in particular 0.05 to 1.5% by weight, based on the amount of the monomers. The optimum amount of initiator naturally depends on the initiator system used and can be determined by the person skilled in the art in routine experiments. The initiator may be partially or completely charged in the reaction vessel. Most of the amount of initiator is initially charged together with part of the monomer emulsion, and the remaining initiator is added continuously or in portions together with the monomers but separately therefrom.

Pressure and temperature are of minor importance for carrying out the polymerization of the monomers. The temperature naturally depends on the initiator system used. The optimum polymerization temperature can be determined by a person skilled in the art with the aid of routine experiments. Usually, the polymerization temperature is in the range of 0 to 110 ⁰ C, often in the range of 30 to 95 ° C. The polymerization is usually carried out at normal pressure or ambient pressure. But it can also at elevated pressure, z. B. to 10 bar or at reduced pressure z. B. at 20 to 900 mbar, but usually be carried out at> 800 mbar. The polymerization time is preferably 1 to 300 minutes, in particular 2 to 90 minutes and particularly preferably 3 to 60 minutes, whereby longer or shorter polymerization times are possible.

As a dispersion stabilizer for stabilizing the resulting emulsion polymers z. B. surface-active substances in an amount of, for example, up to

15 wt .-%, z. B. 0.1 to 10 wt .-%, in particular 0.5 to 5 wt .-%, respectively into the monomers to be polymerized, into consideration. Suitable surface-active substances are, in addition to nonionic surface-active substances, in particular anionic emulsifiers, for. B. alkyl sulfates, alkyl sulfonates, alkylarylsulfonates, Al kylethersulfate, alkylaryl ether sulfates, sulfosuccinates such as sulfosuccinic monoesters and sulfosuccinic and alkyl ether and further cationic emulsifiers.

Examples of suitable nonionic surfactants are ethoxylated mono-, di- and tri-alkylphenols (degree of ethoxylation: 3 to 50, alkyl radical: C3-C12) and ethoxylated fatty alcohols (degree of ethoxylation: 3 to 80, alkyl radical: C8-C36).

Examples include the brands LutensoFder BASF AG or the brands Triton ^® Union Carbide. Particularly preferred are ethoxylated linear fatty alcohols of the general formula

n-CχH ₂ x ₊ iO (CH ₂ CH ₂ O) y H,

where x are integers in the range of 10 to 24, preferably in the range of 12 to 20. The variable y preferably stands for integers in the range from 5 to 50, more preferably 8 to 40. Ethoxylated linear fatty alcohols are usually present as a mixture of different ethoxylated fatty alcohols with different degrees of ethoxylation. The variable y in the context of the present invention stands for the mean value (number average). Suitable nonionic surface-active substances are also copolymers, in particular block copolymers of ethylene oxide and at least one C3-Cio-alkylene oxide, for. B. triblock copolymers of the formula

RO (CH 2 CH 2 O) yi- (BO) y 2 - (AO) _m - (BO) y 3 - (CH 2 CH 2 O) _{y 4} R ',

wherein m is 0 or 1, A is a radical derived from an aliphatic, cycloaliphatic or aromatic diol, e.g. For example, ethane-1, 2-diyl, propane-1, 3-diyl, butane-1, 4-diyl, cyclohexane-1, 4-diyl, cyclohexane-1, 2-diyl or bis (cylohexyl) methane -4,4'-diyl, B and B 'are independently propane-1, 2-diyl, butane-1, 2-diyl or phenethylethany4 independently of one another from 2 to 100 and Y 2, Y 3 independently of one another is a number from 2 to 100, the sum y1 + y2 + y3 + y4 preferably being in the range from 20 to 400, which corresponds to a number-average molecular weight in the range from 1000 to 20,000. Preferably, A is ethane-1, 2-diyl, propane-1, 3-diyl or butane-1, 4-diyl. B is preferably propane-1,2-diyl.

Suitable surface-active substances besides the nonionic surfactants are anionic and cationic surfactants. They can be used alone or as a mixture. The prerequisite for this, however, is that they are compatible with each other. This requirement applies, for example, to mixtures of and mixtures of nonionic and anionic surfactants and mixtures of nonionic and cationic surfactants. Examples of suitable surfactants are sodium lauryl sulfate, sodium dodecylsulfate, sodium hexadecylsulfate and sodium dioctylsulfosuccinate. Examples of cationic surfactants are long-chain ammonium compounds.

Also suitable as dispersion stabilizer are condensates of naphthalenesulfonic acid and formaldehyde, amphiphilic polymers or nanoparticles of water-insoluble organic polymers or water-insoluble inorganic compounds (Pickering effect). Stabilizers of this type are z. As nanoscale silica and alumina or synthetic organic nanoparticles such as crosslinked polyacrylic acid having a particle size of, for example, 10 to 300 nm.

Amphiphilic polymers having an average molecular weight M _w of, for example, 1000 to 100 000 can also be used as a dispersion stabilizer. Examples of amphiphilic polymers are copolymers comprising units of

(a) hydrophobic monoethylenically unsaturated monomers and

(B) monoethylenically unsaturated carboxylic acids, monoethylenically unsaturated sulfonic acids, monoethylenically unsaturated phosphonic acids or mixtures thereof and / or basic monomers

contain.

Suitable hydrophobic monoethylenically unsaturated monomers

(a) are, for example, styrene, methylstyrene, ethylstyrene, acrylonitrile, methacrylonitrile, C2 to Cis olefins, esters of monoethylenically unsaturated C3 to C5 carboxylic acids and monohydric alcohols, vinyl alkyl ethers, vinyl esters or mixtures thereof. From this group of monomers is preferably used

Isobutene, diisobutene, styrene and acrylic esters such as ethyl acrylate, isopropyl acrylate, n-butyl acrylate and sec-butyl acrylate.

The amphiphilic copolymers contain as hydrophilic monomers

(b) preferably acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, vinylsulfonic acid, 2-acrylamidomethylpropanesulfonic acid, acrylamido-propane-3-sulfonic acid, 3-sulfopropyl acrylate, 3-sulfopropyl methacrylate, styrenesulfonic acid, vinylphosphonic acid or mixtures thereof in copolymerized form. The acidic monomers may be in the form of the free acids or in partially or completely neutralized form. Other suitable hydrophilic monomers are basic monomers. They can be polymerized with the hydrophobic monomers (a) alone or in admixture with the acidic monomers mentioned above. When mixtures of basic and acidic monomers are used, amphoteric copolymers are formed, which are anionically or cationically charged, depending on the molar ratio of the copolymerized acidic to basic monomers.

Basic monomers are, for example, di-C 1 to C ₂ -alkylamino-C ₂ to C ₄ -alkyl (meth) acrylates or diallyldimethylammonium chloride. The basic monomers may be in the form of the free bases, the salts with organic or inorganic acids or in the form quaternized with alkyl halides. The salt formation or the quaternization, at which the basic monomers become cationic, can be partial or complete. Examples of such compounds are dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, dimethylaminoethyl acrylate, diethylaminoethyl acrylate, dimethylaminopropyl methacrylate, dimethylaminopropyl acrylate, diethylaminopropyl methacrylate, diethylaminopropyl acrylate and / or dimethylaminoethylacrylamide, dimethylaminoethylmethacrylamide, dimethylaminopropylacrylamide, dimethylaminopropylmethacrylamide and / or diallyldimethylammonium chloride.

If the amphiphilic copolymers in the form of the free acid are not sufficiently soluble in water, they are used in the form of water-soluble salts, for. B. using the corresponding alkali metal, alkaline earth metal and ammonium salts. These salts are prepared, for example, by partial or complete neutralization of the free acid groups of the amphiphilic copolymers with bases, e.g. For example, sodium hydroxide solution, potassium hydroxide solution, magnesium oxide, ammonia or amines such as triethanolamine, ethanolamine, morpholine, triethylamine or butylamine are used for neutralization. Preferably, the acid groups of the amphiphilic copolymers are neutralized with ammonia or sodium hydroxide solution. The solubility in water of basic monomers or of copolymers which comprise such monomers in copolymerized form can, on the contrary, be increased by partial or complete neutralization with a mineral acid such as hydrochloric acid or sulfuric acid or by addition of an organic acid such as acetic acid or p-toluenesulphonic acid. The molecular weight of the amphiphilic copolymers is, for example, from 1000 to 100,000 and is preferably in the range from 1500 to 10,000. The acid numbers of the amphiphilic copolymers are, for example, from 50 to 500, preferably from 150 to 350, mg KOH / g of polymer.

Particularly preferred are such amphiphilic copolymers, the

(A) 95 to 45 wt .-% of isobutene, diisobutene, styrene or mixtures thereof and (b) 5 to 55 wt .-% acrylic acid, methacrylic acid, maleic acid, half esters of maleic acid or mixtures thereof incorporated in copolymerized form. Copolymers are particularly preferably used as dispersion stabilizer, the

(A) 45 to 80 wt .-% of styrene, (b) 55 to 20 wt .-% acrylic acid and optionally (c) additionally other monomers

incorporated in copolymerized form. If appropriate, the copolymers may contain polymerized units of maleic monoesters as further monomers (c). Such copolymers are obtainable, for example, by copolymerizing copolymers of styrene, diisobutene or isobutene or mixtures thereof with maleic anhydride in the absence of water and reacting the copolymers with alcohols after the polymerization, with from 5 to 50 per mole of anhydride groups in the copolymer Mol% of a monohydric alcohol. Suitable alcohols are, for example, methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol and tert-butanol. However, it is also possible to react the anhydride groups of the copolymers with polyhydric alcohols, such as glycol or glycerol. However, the reaction is carried out only to the extent that only one OH group of the polyhydric alcohol reacts with the anhydride group. If the anhydride groups of the copolymers are not completely reacted with alcohols, the ring opening of the anhydride groups not reacted with alcohols is effected by addition of water.

Other suitable dispersion stabilizers are, for example, commercially available polymers of monoethylenically unsaturated acids and also graft polymers of N-vinylformamide on polyalkylene glycols, which are described, for example, in WO-A-96/34903. The grafted vinylformamide units may optionally be hydrolyzed. The proportion of grafted vinylformamide units is preferably 20 to 40 wt .-%, based on polyalkylene glycol. Polyethylene glycols having molecular weights of 2,000 to 10,000 are preferably used.

Also suitable as a dispersion stabilizer zwitterionic polyalkylenepolyamines and zwitterionic polyethyleneimines into consideration. Such compounds are known for example from EP-B 1 12 592. They are obtainable, for example, by first alkoxylating a polyalkylene polyamine or polyethyleneimine, eg. With ethylene oxide, propylene oxide and / or butylene oxide and the alkoxylation products are then quaternized, for. B. with methyl bromide or dimethyl sulfate and the quaternized, alkoxylated products then sulfated with chlorosulfonic acid or sulfur trioxide. The molar mass of the zwitterionic polyalkylenepolyamines is, for example, 1000 to 9000, preferably 1500 to 7500. The zwitterionic polyethyleneimines preferably have molecular weights in the range from 1500 to 7500 daltons. Further suitable dispersion stabilizers are protective colloids. They generally have average molecular weights M _w of above 500, preferably of more than 1000. Examples of protective colloids are polyvinyl alcohols, cellulose derivatives such as carboxymethyl cellulose, polyvinylpyrrolidone, polyethylene glycols, graft polymers of vinyl acetate and / or vinyl propionate on polyethylene glycols, with one or both sides Alkyl, carboxyl or amino groups end-capped polyethylene glycols, polydiallyldimethylammonium chlorides and / or polysaccharides such as in particular water-soluble starches, starch derivatives and proteins. Such products are described for example in Römpp, Chemie Lexikon 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 by E. Husemann and R. Werner, pages 862-915 and in Ullmann's Encyclopedia for Industrial Chemistry, 6th edition, volume 28, pages 533 ff under polysaccharides.

Suitable examples are all types of water-soluble starch, eg. For example, both amylose and amylopectin, native starches, hydrophobically or hydrophilically modified starches, anionic starches, cationically modified starches, degraded starches, wherein the starch degradation can be carried out, for example oxidatively, thermally, hydrolytically or enzymatically and wherein for the starch degradation both native as well as modified starches can be used. Other suitable protective colloids are dextrins and crosslinked water-soluble starches which are water-swellable.

Native, water-soluble starches which can be converted into a water-soluble form, for example by means of starch digestion, and anionically modified starches, such as oxidized potato starch, are preferably used as the protective colloid. Particularly preferred are anionically modified starches which have been subjected to molecular weight degradation. The molecular weight degradation is preferably carried out enzymatically. The average molecular weight M _{w of} the degraded starches is, for example, 500 to 100,000, preferably 1,000 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-257 412 and EP-B 276 770. If protective colloids are used in the polymerization, the amounts used are, for example, from 0.5 to 50, in particular from 5 to 40, preferably from 10 to 30,% by weight, based on the monomers used in the polymerization.

Of course, it is possible to add further additives to the polymerization mixture which are customary in emulsion polymerization, for example glycols, polyethylene glycols, buffers / pH regulators, molecular weight regulators and chain transfer inhibitors. An aqueous polymer dispersion containing at least one effect substance is obtained, the effect substances being at least partially enveloped by the water-insoluble polymer formed from the monomers. It is observed no measurable or very low levels of agglomerates, which usually account for less than 2 wt .-%, preferably less than 0.2 wt .-%, based on the solids contained in the dispersion.

It is possible, as already explained above, in a further step, to subject the aqueous polymer dispersions obtainable in this way, which contain at least one effect substance, preferably one type of UV absorber, in a further process step to an additional emulsion polymerization in order to vary the properties of the polymer particles , In this case, it is possible to polymerize another monomer or a different mixture of monomers onto the dispersed polymer particles so that particles having a core / shell structure are formed. These particles may contain a single shell or, if the emulsion polymerization is repeated with another composition of the monomers or effect substances, also several shells, e.g. B. 2, 3, 4 or even 5 different shells. The polymer matrix of the shell of such structures may be uncrosslinked or preferably crosslinked. For example, if core / shell polymer particles are prepared, the weight ratio of polymer in the core to polymer in the shell is 5: 1 to 1: 5, preferably 2: 1 to 1: 2.

From the above-described aqueous dispersions containing at least effect substance, preferably a UV absorber, polymer powders containing effect substances can be obtained by evaporating the volatile constituents of an aqueous polymer dispersion containing effect substances. Preferably, such powders are prepared from the described dispersions by spray drying.

The polymer dispersions containing effect substances or the polymer powders obtained therefrom are used for equipping and / or stabilizing polymers, in particular against the action of UV radiation. They are incorporated, for example, in thermoplastic polymers such as polyethylene, polypropylene, polyamide, polyacrylonitrile, polycarbonate, polyvinyl chloride or polyester. For example, it requires amounts of polymers containing effect substances, preferably polymers containing UV absorbers, of from 0.1 to 3, preferably from 0.5 to 2,% by weight, based on the polymer to be finished.

In order to stabilize a thermoplastic polymer against UV exposure, it is possible, for example, to melt the polymer first in an extruder, then to prepare a powder containing UV absorbers prepared according to the invention in the polymer melt at a temperature of 180 to 200 ° C. incorporated and from this produces a granulate from which films are then prepared by known methods, which are stabilized against the action of UV radiation.

Examples

The percentages in the examples are by weight unless otherwise indicated in the context.

The particle sizes were measured with a Coulter N4 Plus laser diffraction instrument or alternatively with a Coulter 230 LS. It was generally measured in 0.01% by weight aqueous preparations.

The glass transition temperature T ₉ was determined by differential thermal analysis (DSC) in accordance with ASTM D 3418-82.

example 1

116.3 g of deionized water were placed in a N2 purged reactor and brought to 80 ° C internal temperature with stirring. Then 13.05 g of a mixture of 1 l, 69 g of deionized water and 40.5 g of a 2% sodium peroxodisulfate solution (feed 3) were added all at once. A mixture of 405.8 g of deionized water, 9.9 g of Dowfax® 2A1 (45% strength aqueous solution of a surfactant: di-sodium salt of dodecyldiphenyl ether disulfonic acid), 3.24 g, was then added over 3.5 hours Allyl methacrylate and 173.88 g of methyl methacrylate (feed 1) to. At the same time, the remainder of feed 3 was metered into the reaction mixture over a period of 5 hours.

After completion of feed 1 polymerized for 30 min after. Now dosed a mixture of 175 g of deionized water, 0.9 g Dowfax® 2A1, 92.88 g of methyl methacrylate and 54 g of 4-n-octyloxy-2-hydroxy-benzophenone (Uvinul 3008) (feed 2), which in the monomer was dissolved in 1 h. Then a solution of 3.59 g of deionized water and 5.4 g of a 10% aqueous tert-butyl hydroperoxide solution (feed 4) and 4.05 g of Rongalit® C (10% aqueous solution of an addition product of Sodium hydrogen sulfite on formaldehyde) and 4.94 g of deionized water (feed 5) over a period of 60 minutes.

The reaction mixture was then allowed to cool to room temperature and the dispersion filtered through a 500 μm and then through a 125 μm filter to remove the coagulum. The amount of coagulum separated was 5.5 g. The dispersion had a solids content of 28.1% and contained 333 ppm of residual monomer (methylene chloride). methacrylate). The average particle size was 173 nm. The polymer had a glass transition temperature T ₉ of 93 ° C.

Under a light microscope, no crystals of the UV absorber could be seen in the dispersion at 1000X magnification, i. the UV absorber is present in polymeric matrix.

Spray-drying of the aqueous dispersion gave a loose white powder, from which a Debye-Scherrer powder diagram was taken. The uptake clearly showed that the UV absorber in the polymeric matrix was amorphous and not crystalline.

Example 2

116.3 g of deionized water were placed in a N2 purged reactor and brought to 80 ° C internal temperature with stirring. Then 13.05 g of a mixture of 1 l, 69 g of deionized water and 40.5 g of a 2% sodium peroxodisulfate solution (feed 3) were added all at once. Subsequently, a mixture of 470.09 g of deionized water, 9.9 g of Dowfax® 2A1, 3.24 g of allyl methacrylate, 173.88 g of methyl methacrylate and 54 g of 4-n-octyloxy-2-hydroxy was metered in over 3.5 hours - Benzophenone, which was dissolved in the monomers (feed 1), too. At the same time, the remainder of feed 3 was added over a period of 5 hours.

After completion of feed 1, the reaction mixture was polymerized for a further 30 minutes. Subsequently, a mixture of 110.7 g of deionized water, 0.9 g of Dowfax® 2A1, 92.88 g of methyl methacrylate (feed 2) was metered in within 1 hour. Then, a solution of 3.59 g of deionized water and 5.4 g of a 10% aqueous solution of tert-butyl hydroperoxide (feed 4) and 4.05 g of Rongalit® C and 4.94 g of deionized water (feed 5 ) over a period of 60 minutes. The reaction mixture was then allowed to cool to room temperature and the dispersion was filtered through a 500 μm filter and then through a 125 μm filter to remove coagulum. The amount of coagulum separated was 3.2 g and 0.7 g, respectively, and the solids content was determined to be 30.4%. The mean particle size was 219 nm. The polymer had a glass transition temperature T ₉ of 92 ° C.

In the dispersion, no crystals of 4-n-octyloxy-2-hydroxy-benzophenone were visible under a light microscope at 1000 × magnification, ie the UV absorber is present in polymeric matrix. Spray drying the dispersion gave a white powder. From the powder, a Debye-Scherrer powder diagram was taken which clearly showed that the UV absorber in the polymeric matrix was amorphous and not crystalline.

Example 3

116.3 g of deionized water were placed in a N2 purged reactor and brought to an internal temperature of 80 ° C with stirring. Then, 13.05 g of a mixture of 1 l, 69 g of deionized water and 40.5 g of a 2% sodium peroxodisulfate solution (feed 2) were added all at once. A mixture of 580.79 g of deionized water, 10.8 g of Dowfax® 2A1, 3.24 g of allyl methacrylate, 266.76 g of methyl methacrylate and 54 g of 4-n-octyloxy was then added over 3.5 hours as feed 1. 2-hydroxybenzophenone (Uvinul 3008) dissolved in the monomers. At the same time, the remainder of feed 2 was also metered in over a period of 3.5 hours. After completion of feeds 1 and 2, the reaction mixture was polymerized for a further 30 minutes. Subsequently, a mixture of 3.59 g of deionized water, 5.4 g of tert-butyl hydroperoxide (feed 3) was metered in together with a mixture of 4.05 g of Rongalit® C and 4.94 g of deionized water (feed 4) within 1 hour to.

Thereafter, the reaction mixture was allowed to cool to room temperature and the dispersion was filtered through a 500 μm and then through a 125 μm filter to remove the coagulum. The amount of coagulum separated was 4.1 g (500 μm filter) and 9 g (125 μm filter). The solids content of the dispersion was 28.3%. The mean particle size was 288 nm.

In the dispersion, no crystals of 4-n-octyloxy-2-hydroxybenzophenone were visible under a light microscope at 1000 × magnification, ie the UV absorber was present in polymeric matrix. Spray drying the dispersion gave a white powder. The glass transition temperature of the polymer was determined to be 98.1 ° C.

The following table shows the change with time of the particle size and the solids content during the preparation of the dispersion.

Example 4

116.3 g of deionized water were placed in a N2 purged reactor and brought to an internal temperature of 80 ° C with stirring. Then, 13.05 g of a mixture of 11.69 g of deionized water and 40.5 g of a 2% sodium peroxodisulfate solution (feed 2) were added all at once. A mixture of 580.79 g of deionized water, 10.8 g of Dowfax® 2A1, 3.24 g of pentaerythritol tetraacrylate, 266.76 g of methyl methacrylate and 54 g of 4-n-octyloxy was then added over 3.5 hours as feed 1. 2-hydroxy-benzophenone, which was dissolved in the monomers to. At the same time, the remainder of feed 2 was also metered in over a period of 3.5 hours. After complete dosing of feeds 1 and 2, the reaction mixture was stirred for a further 30 minutes. Then, a mixture of 3.59 g of deionized water, 5.4 g of tert-butyl hydroperoxide (feed 3) together with a mixture of 4.05 g Rongalit C (feed 4) within 1 hour. The mixture was then allowed to cool to room temperature and the dispersion first filtered through a 500 μm and then through a 125 μm filter to remove the coagulum. The Amount of the separated coagulum was 1 g and 18 g (125 μm filter); the solids content of the dispersion was determined to be 27.2%. The mean particle size of the dispersed particles was 303 nm.

In the aqueous dispersion, no crystals of 4-n-octyloxy-2-hydroxy-benzophenone were seen under a light microscope at 1000 times magnification, which means that the UV absorber was present in polymeric matrix. Spray drying the dispersion gave a white powder. The glass transition temperature T ₉ of the polymer was determined to 104.9 ⁰ C.

Claims

claims

1. Aqueous polymer dispersions whose dispersed particles contain at least one effect substance from the group of UV absorbers, antistatic agents, antioxidants and anti-fogging agents have an average particle size of at most 500 nm and which are obtainable by emulsion polymerization of ethylenically unsaturated monomers in the presence of at least one Effektstoffs, characterized in that the matrix polymers of the dispersed particles have a glass transition temperature of at least 85 ° C.

2. Aqueous polymer dispersions according to claim 1, characterized in that the dispersed polymer particles have a core / shell structure and that the matrix polymers have a glass transition temperature Tg of at least 95 ° C and in the core, in the shell or in the core and in the shell at least contain an effect substance.

3. Aqueous polymer dispersion according to claim 1 or 2, characterized in that the matrix polymers contain at least one non-polymerizable UV absorber.

4. Aqueous polymer dispersions according to any one of claims 1 to 3, characterized in that the dispersed polymer particles have a core / shell structure and contain at least one UV absorber in the core.

5. Aqueous polymer dispersions according to any one of claims 1 to 4, characterized in that the polymer matrix of the dispersed individual particles of the dispersion or the core of the polymer particles is crosslinked with core / shell structure.

6. Aqueous dispersions according to claim 5, characterized in that the crosslinked polymer of at least one monomer of the group

(i) C 1 to C 10 alkyl acrylates, C 1 to C 10 alkyl methacrylates, styrene, acrylonitrile and methacrylonitrile, and

(ii) at least one crosslinker selected from the group of allyl acrylate, allyl methacrylate,

Pentaerythritol triacrylate, pentaerythritol tetraacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, butanediol diacrylate, ethylene glycol diacrylate, e thylanglycol dimethacrylate, butanediol dimethacrylate, trimethylolpropane triacrytate, trimethylolpropane trimethacrylate, butadiene, divinylbenzene, divinylurea and methylenebisacrylamide

is constructed.

7. Aqueous dispersions according to any one of claims 1 to 6, characterized in that the UV absorber is 4-n-octyloxy-2-hydroxy-benzophenone.

8. At least one effect substance from the group of UV absorbers, antistatic agents, antioxidants and antifogging agent-containing polymer powder, obtainable by evaporation of the volatile constituents of an aqueous, the effect substances containing polymer dispersions according to claims 1 to 7.

9. Use of at least one effect substance from the group of UV absorbers, antistatic agents, antioxidants and antifogging agent-containing polymer powder according to one of claims 1 to 7 for the equipment and for stabilizing organic polymers.

10. Use according to claim 9, characterized in that one uses UV absorber-containing polymer dispersions or the polymer powder obtained therefrom for the stabilization of thermoplastic polymers against the action of UV radiation.