EP1835986A2

EP1835986A2 - Use of statistical copolymers as dispersants

Info

Publication number: EP1835986A2
Application number: EP05769764A
Authority: EP
Inventors: Matthias Koch; Ralf Anselmann
Original assignee: Merck Patent GmbH
Current assignee: Merck Patent GmbH
Priority date: 2004-08-27
Filing date: 2005-08-03
Publication date: 2007-09-26
Also published as: WO2006024357A2; US20080093586A1; JP2008510602A; TW200621355A; DE102004041536A1; WO2006024357A3; CN101048226A; EP1905417A3; EP1905417A2

Abstract

The invention relates to the use of statistical copolymers containing at least one structural unit with hydrophobic radicals and at least one structural unit with hydrophilic radicals as dispersants for producing dispersions with an incompatible disperse and continuous phase, in particular, for dispersing particles with a hydrophilic surface in oils, dispersions or powder compositions, containing statistical copolymers and particles with a hydrophilic surface. The invention also relates to methods for producing these statistical copolymers.

Description

Use of random copolymers

The invention relates to the use of random copolymers as dispersants for the preparation of dispersions with incompatible disperse and continuous phase, in particular for dispersing particles having a hydrophilic surface in oils, dispersions or powder compositions containing random copolymers and particles having a hydrophilic surface and processes for their preparation ,

Dispersions are used in many areas. So are paints and varnishes, as well as cosmetic and pharmaceutical

Preparations, as well as cleaning and coating agents frequently

Dispersions of particles in liquids. An essential

The problem with the use of dispersions is the tendency of particles to form agglomerates, whereby the storage stability of the

Dispersions can be affected. Therefore, there is a continuing need for improved dispersants that provide stable dispersions.

Further, it is important for the stability of dispersions that disperse and continuous phases are compatible. Hydrophilic particles can be relatively easily dispersed in water using dispersants, but it is difficult to form dispersions with oils. To compatibilize such non-compatible phases, dispersants which mediate between the phases are common.

However, some of these are very high concentrations

Dispersing aids required to produce stable dispersions.

For the preparation of stable dispersions of highly hydrophilic particles in oils, no truly satisfactory dispersants are available.

Therefore, there is still a need for dispersants that allow stable dispersions with incompatible disperse and continuous Phase, in particular to produce dispersions of hydrophilic particles in oils.

Surprisingly, it has now been found that certain copolymers are outstandingly suitable as dispersants for the preparation of dispersions with incompatible disperse and continuous phase.

A first subject of the present invention is therefore the use of random copolymers comprising at least one structural unit having hydrophobic radicals and at least one structural unit having hydrophilic radicals as dispersants for the preparation of dispersions with incompatible disperse and continuous phase.

Particular preference is given to using random copolymers comprising at least one structural unit having hydrophobic radicals and at least one structural unit having hydrophilic radicals as dispersant for dispersing particles having a hydrophilic surface in oils.

A further subject of the present invention accordingly oily dispersion containing hydrophilic particles, characterized in that as dispersing agent at least one random copolymer containing at least one structural unit with hydrophobic radicals and at least one structural unit having hydrophilic radicals is contained.

An inventive method for producing an oily

Dispersion of hydrophilic particles, is characterized in that random copolymers containing at least one structural unit having hydrophobic radicals and at least one structural unit having hydrophilic radicals are mixed with an oil and hydrophilic particles. In a preferred variant, the random copolymers are initially charged in an oil and then the hydrophilic particles are added. In another preferred variant For example, an aqueous dispersion of hydrophilic particles is mixed (emulsified) with a solution of a random copolymer in a hydrophobic solvent and then the water or both solvents are removed.

An inventive method for producing an aqueous

Dispersion of hydrophobic particles is characterized in that random copolymers comprising at least one structural unit having hydrophobic radicals and at least one structural unit having hydrophilic radicals are mixed with water and hydrophobic particles. In this case, the random copolymers are preferably initially introduced into water, and then the hydrophobic particles are added.

The preparation of the dispersions, in particular of oily dispersions, in a preferred embodiment of the present invention can be carried out starting from redispersible particles. Corresponding powder compositions containing hydrophilic particles, characterized in that the hydrophilic particles are coated with at least one random copolymer containing at least one structural unit having hydrophobic radicals and at least one structural unit having hydrophilic radicals, are therefore also an object of the present invention.

The powder compositions can be obtained by preparing a dispersion according to the procedures given above and then removing the solvent.

In the powder compositions of the invention, particles having a hydrophilic surface are usually contained in a weight fraction of from 20 to 95% by weight, preferably from 30 to 80% by weight, based on the powder composition.

The choice of random copolymers of at least one monomer having hydrophobic radicals and at least one monomer having hydrophilic radicals has now succeeded in dispersants - A -

to provide the dispersing of particles with hydrophilic surface in hydrophobic media and vice versa. At the same time, the use of these novel dispersants makes it possible to isolate the particles from agglomerate-free as a redispersible powder composition from the dispersions to 5, since the individual particles can be separated directly in a polymer-coated manner.

The dispersions which can be prepared with the aid of the random copolymers are distinguished by excellent stability. In addition, H Q often suffice comparatively small amounts of the copolymers for the preparation of stable dispersions.

In addition, the powder compositions obtainable by this method can be particularly easily and uniformly redispersed.

15

A further advantage is that little or no agglomerates of the dispersed particles form in the dispersions according to the invention. In particular, an undesirable impairment of the transparency of such dispersions in the visible light, if correspondingly small particles are dispersed, largely avoided

20 will be.

Preferably, the dispersed particles have an average particle size determined by means of dynamic light scattering or transmission electron microscopy of 3 to 200 nm, in particular of

20 to 80 nm and most preferably from 30 to 50 nm. In 5 specific also preferred embodiments of the present invention

The invention is the distribution of particle sizes narrow, i. the fluctuation range is less than 100% of the mean value, in particular preferably not more than 50% of the mean value.

_Q In a further variant of the present invention the dispersed particles have an average particle size ranging from 500 to 5000 nm. Likewise, it may be preferred according to the invention Anisotropic particles, particularly preferably platelets with a thickness in the range of 500 to 5000 nm and a diameter in the range of 5 to 100 microns to disperse.

Particularly advantageous is the use of the dispersant according to the invention for dispersing hydrophilic particles having a metal (hydr) oxide surface, wherein the metal (hydr) oxide is preferably selected from oxides or hydroxides of silicon, aluminum, magnesium, antimony, cerium , Cobalt, chromium, indium, nickel, zinc, titanium, iron, yttrium, tin, zirconium, and mixtures thereof. Such particles are very difficult to wet with oils and are therefore considered to be difficult to disperse in oils with conventional dispersants. It is particularly preferred according to the invention for dispersing silica particles or silica-coated particles.

For example, it is possible to use silica particles which can be obtained, for example, by the process described in US Pat. No. 4,911,903. The cores are produced by hydrolytic polycondensation of tetraalkoxysilanes in an aqueous-ammoniacal medium, wherein first of all a sol of primary particles is produced and subsequently separated by a continuous,

20 controlled metered addition of tetraalkoxysilane brings the resulting SiO ₂ - particles to the desired particle size. With this method, monodisperse SiO ₂ nuclei with average particle diameters between 0.05 and 10 μm can be produced with a standard deviation of 5%. Corresponding products are under the

Trade name Monospher® (Merck) in the trade. 25

Furthermore, it is possible to use SiO ₂ particles coated with (semi-) metals or in the visible range nonabsorbing metal oxides such as TiO ₂ , ZrO ₂ , ZnO ₂ , SnO ₂ or Al ₂ O ₃ . The preparation of coated with metal oxides SiO ₂ cores is described in detail _on, for example, in US 5,846,310, DE 198 42 134 and DE 199 29 109th So can also monodisperse particles from nonabsorbing

Metal oxides such as TiO ₂ , ZrO ₂ , ZnO ₂ , SnO ₂ or Al ₂ O ₃ or

Metal oxide mixtures are used. Their preparation is described, for example, in EP 0 644 914. Furthermore, that is

Process according to EP 0 216 278 for the preparation of monodisperse SiO ₂ -

Particles readily and with the same result transferable to other oxides. To a mixture of alcohol, water and ammonia, whose temperature is adjusted with a thermostat to 30 to 40 ⁰ C, are added with intensive mixing tetraethoxysilane, tetrabutoxy, Tetrapropoxyzirkon or mixtures thereof in one pour and the resulting mixture for another 20 seconds intensively stirred, forming a suspension of monodisperse particles in the nanometer range. After a post-reaction time of 1 to 2 hours, the cores are separated in the usual manner, for example by centrifuging, washed and dried.

Other silica particles which can likewise be advantageously dispersed by the method described in the present invention are commercially available, for example, under the trade names Ronaspher® (Merck) or Aerosil® (Degussa). In general, with the polymers to be used according to the invention, silica particles of virtually any design can be dispersed. Thus, the particles may be e.g. spherical, hollow, platy porous or non-porous, rod-shaped, platy or amorphous and thus be designed without special geometrical spatial form.

Corresponding particles can be used, for example, as filling materials or for coating.

Furthermore, in a preferred embodiment of the present invention, the particles to be dispersed may be capsules. Capsules which are particularly preferred for use in accordance with the invention have walls which can be obtained by a sol-gel process as described in applications WO 00/09652, WO 00/72806 and WO 00/71084. Preferred are here again capsules whose walls are made of silica gel (silica, undefined silicon oxide hydroxide). The production of such capsules is known to the skilled worker, for example, from the cited patent applications, whose contents are expressly also part of the subject of the present application. Particularly preferred are capsules which contain UV filters. Both for UVA and UVB filters, there are many literature proven substances known, for example benzylidenecamphor derivatives such as 3- (4 ^'- methylbenzylidene) -DL-camphor (eg Eusolex® 6300), 3-benzylidenecamphor (eg Mexoryl® SD) , Polymers of N - {(2 and 4) - [(2

.JQ oxobom-3-ylidene) methyl] benzyl} -acrylamide (eg Mexoryl® SW), N, N, N-trimethyl-4- (2-oxobrom-3-ylidenemethyl) anilinium methylsulfate (eg Mexoryl® SK) or ( 2-oxoborn-3-ylidene) toluene-4-sulfonic acid (eg Mexoryl® SL), benzoyl or dibenzoylmethanes such as 1- (4-tert-butylphenyl) -3- (4-methoxyphenyl) propane-1,3-dione ( eg Eusolex® 9020) or 4-isopropyldibenzoylmethane (eg Eusolex® 8020),

15 benzophenones such as 2-hydroxy-4-methoxybenzophenone (eg Eusolex® 4360) or 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid and its sodium salt (eg Uvinul® MS-40), methoxycinnamate such as octyl methoxycinnamate (eg Eusolex® 2292), 4

Isopentyl methoxycinnamate, e.g. as a mixture of the isomers (e.g., Neo Heliopan® E 1000), salicylate derivatives such as 2-ethylhexyl salicylate (e.g.

²⁰ Eusolex® OS), 4-isopropylbenzylsalicylate (eg Megasol®) or 3,3,5-trimethylcyclohexylsalicylate (eg Eusolex® HMS), A-

Aminobenzoic acid and derivatives such as 4-aminobenzoic acid, 2-ethylhexyl 4- (dimethylamino) benzoate (e.g., Eusolex® 6007), ethoxylated 4-aminobenzoic acid ethyl ester (e.g., Uvinul® P25),

Phenylbenzimidazole sulfonic acids, such as 2-phenylbenzimidazo! -5-

25 sulfonic acid and its potassium, sodium and triethanolamine salts (e.g.

Eusolex® 232), 2,2- (1,4-phenylene) bisbenzimidazole-4,6-disulfonic acid or its salts (eg Neoheliopan® AP) or 2,2- (1,4-phenylene) bisbenzimidazole-6 sulfonic acid; and other substances like

" _N -2-cyano-3,3-diphenylacrylic acid 2-ethylhexyl ester (eg Eusolex® OCR), 3,3 ^' - (1,4-phenylenedimethylene) bis- (7,7-dimethyl-2-oxobicyclo [2.2.1] hept-1-ylmethanesulfonic acid and its salts (eg Mexoryl® SX) and

- 2,4,6-trianilino- (p-carbo-2 ^{^{'-ethylhexyl-1'}} -oxi) -1, 3,5-triazine (for example Uvinul T 150)

Hexyl 2- (4-diethylamino-2-hydroxybenzoyl) benzoate (e.g., Uvinul® UVA Plus, BASF).

The compounds listed in the list are only auf¬ approach as examples. Of course, other UV filters can also be used in the capsules. Preferred compounds having UV-filtering properties are 3- ^{(4'-methylbenzylidene)} -dl-camphor, 1 - (4-tert-butylphenyl) -3- (4-methoxy-phenyl) -pro pan-1, 3-dione , 4-

Isopropyldibenzoylmethane, 2-hydroxy-4-methoxybenzophenone, octyl methoxycinnamate, SSδ-trimethylcyclohexyl-salicylate, 4- (dimethylamino) benzoic acid 2-ethylhexyl ester, 2-cyano- 3,3-di-phenyl-2-ethylhexyl acrylate, 2-phenylbenzimidazole-5-sulfonic acid and its potassium, sodium and triethanolamine salts.

For example, commercially available from Merck KGaA under the name Eusolex®UV Pearl ™ OMC is an SiO ₂ capsule containing octyl methoxycinnamate as a UV filter.

Furthermore, it may be preferred according to the invention to disperse inorganic UV filters. Nanoparticulate metal oxides are preferably used for the inventive use as inorganic UV filters. Thus, in particular titanium dioxide, iron oxides, zinc oxide or even cerium oxides are suitable for use as UV filters, with titanium dioxide being particularly preferred according to the invention as metal oxide since it fulfills the objects of the invention in a particular way. Titanium dioxide can be present in the form of rutile or anatase or in amorphous form, but preferably in the form of rutile and / or anatase. The primary particle size is preferably in the range from 5 to 50 nm, whereby the primary particles are preferably round, especially in the case of anatase, while rutile primary particles frequently occur in needle or spindle form as far as ovals ("egg-shaped"). Primary particles are used, with preferred inorganic UV filters having one Silica coating that covers the nanoparticulate metal oxide as completely as possible. It has been shown that it is advantageous if the silicon dioxide content based on the entire nanoparticulate UV protection agent is 5 to 50 wt .-%, preferably 8 to 30 wt .-% and particularly preferably 12 to 20 wt .-%. The resulting nanoparticulate UV protection agent usually has a particle size by the Scherrer method in the range of 5 nm to 100 nm, preferably in the range 8 to 50 nm and particularly preferably below 25 nm

Transmission electron microscope can be determined dimensions of the

Typically, the length of the nanoparticulate UV protection agent is from 5 to 160 nm in length and 10 to 70 nm in width. Preferably, the length is in the range of 30 to 70 nm and the width in the range of 18 to 40 nm. This inorganic UV Filters are usually incorporated in an amount of 0.5 to 20 percent by weight, preferably 2 - 10%, in cosmetic preparations. Particularly preferred

According to the invention, the use of the copolymers for dispersing silica-coated titanium dioxide, which is commercially available, for example, under the name Eusolex® T-AVO (Merck KGaA).

The particles having a hydrophilic surface are usually dispersed in a proportion by weight of from 1 to 90% by weight, preferably from 10 to 60% by weight, based on the dispersion.

The dispersant is usually used in a concentration of 0.5 to 80% by weight, preferably in a concentration of 1 to 50% by weight and more preferably in a concentration of 2 to 8% by weight.

%, based on the total dispersion used. 5

According to the invention preferably to be random copolymers show here a weight ratio of structural units containing hydrophobic radicals to structural units containing hydrophilic radicals in the random copolymer is in the range 1: 10 to 500: 1, preferably ₀ in the range 1: 2 to 100: 1 and particularly preferably in the range 1: 1 to 10: 1. The weight average molecular weight of the preferred random copolymers is in the range of M _w = 1000 to 1,000,000 g / mol, preferably in the range of 2,000 to 50,000 g / mol.

It has been found that in particular copolymers which correspond to the formula I, wherein

X and Y correspond to the radicals of conventional nonionic or ionic monomers, and

R ¹ is hydrogen or a hydrophobic side group, preferably selected from the branched or unbranched alkyl radicals having at least 4 carbon atoms in which one or more, preferably all hydrogen atoms are replaced by fluorine atoms

^ c can, and

R ² is a hydrophilic side group which preferably has one or more phosphonate, phosphate, phosphonium, sulfonate, sulfonium, (quaternary) amine, polyol or polyether radicals, more preferably one or more hydroxyl radicals means that the respective groups in the polymer are distributed statistically

20 are arranged, and wherein within a molecule -XR ¹ and -YR ^{2 may} each have several different meanings and the copolymers in addition to the structural units shown in formula I further structural units, preferably those without or with short side chains, such as C-ι _-4 Alkyl, the inventive

25 fulfill requirements in a special way.

Again, particular preference is given to those polymers of the formula I in which X and Y independently of one another represent -O-, - C (OO) -O-, -C (OO) -NH-, - (CH ₂ ) n -, phenyl, naphthyl or pyridiyl. Furthermore, polymers can be used in which at least one structural unit

30 contains at least one nitrogen or phosphorus quaternary atom, where R ^{2 is} preferably a side group ~ (CH ₂ ) m - (N ⁺ (CH ₃ ) ₂ ) - (CH ₂ ) n-SO ₃ ^~ or a side group - (CH ₂ ) _m - (N ⁺ (CH 3) 2) - (CH ₂ ) n PO ₃ ^{2 -} , - (CH ₂ ) m - (N ⁺ (CH 3 ) 2) - (CH ₂ ) nO-Pθ 3 ^{2 "} or a side group - (CH ₂ ), * - (P ⁺ (CH ₃ ) ₂ ) - (CH ₂ ) n -SO ₃ ^" , where m is an integer Number from the range of 1 to 30, preferably from the range 1 to 6, particularly preferably 2, and n is an integer from the range of 1 to 30, preferably from the range 1 to 8, particularly preferably 3, advantageously use ,

Particularly preferred random copolymers can be prepared according to the method described in DE 10 2004 004 210.1, according to the following scheme:

The desired amounts of lauryl methacrylate (LMA) and dimethylaminoethyl methacrylate (DMAEMA) are copolymerized by known methods, preferably in toluene, by addition of AIBN radical. Subsequently, a betaine structure is obtained by reacting the amine with 1, 3-propane sultone by known methods.

In a particularly preferred variant, a copolymer of lauryl methacrylate (LMA) and hydroxyethyl methacrylate (HEMA) is used.

OK used. These polymers are also preferably copolymerized by radical polymerisation of the monomers in toluene by addition of AIBN.

Alternative preferred copolymers to be used may contain styrene, vinylpyrilidone, vinylpyridine, halogenated styrene or methoxystyrene, these examples being not limiting. In another also preferred embodiment of the present invention Invention polymers are used, which are characterized in that at least one structural unit is an oligo- or polymer, preferably a macromonomer, with polyethers, polyolefins and polyacrylates are particularly preferred as macromonomers.

It may be further preferred according to the invention if the random copolymers contain at least one structural unit which has a phosphonium or sulfonium radical.

It may further be preferred according to the invention if, in addition to the at least one structural unit having hydrophobic radicals and the at least one structural unit having hydrophilic radicals, further structural units, preferably those without hydrophilic or hydrophobic side chains or short side chains, such as, for example, C _1-4 , are present in the random copolymers. Alkyl are included.

In certain cases, it may be helpful if, in addition to the random copolymer, a further dispersant, preferably a nonionic surfactant, is used. Preferred codispersant are optionally ethoxylated or propoxylated, relatively long-chain alkanols or alkylphenols having different degrees of ethoxylation or propoxylation (for example adducts with 0 to 50 moles of alkylene oxide;. For example, commercially available from BASF under the trade name Lutensol ^®.).

Also, dispersants can be used advantageously, preferably water-soluble high molecular weight organic compounds with polar groups, such as polyvinylpyrrolidone, copolymers of

Vinyl propionate or acetate and vinylpyrrolidone, partially hydrolyzed

Copolymeriste of an acrylic ester and acrylonitrile, polyvinyl alcohols having different residual acetate content, cellulose ethers, gelatin, block copolymers, modified starch, low molecular weight, carbon- and / or sulfonic acid-containing polymers or mixtures of these substances can be used. Particularly preferred protective colloids are Polyvinyϊalkohole having a residual acetate content of less than 40, in particular 5 to 39 mol .-% and / or vinylpyrrolidone A / inylpropionat copolymers having a vinyl ester content of less than 35, in particular 5 to 30 wt .-%.

The oily phase can be selected advantageously from the following

Group of substances:

- mineral oils, mineral waxes

- Oils such as triglycerides of capric or caprylic, further natural oils such. Castor oil; Organic solvents, such as saturated and unsaturated, cyclopean and / or acyclic hydrocarbon compounds, which may optionally contain heteroatoms such as O, N, S and P,

Fats, waxes and other natural and synthetic fats, preferably esters of fatty acids with lower C-number alcohols, e.g. with isopropanol, propylene glycol or glycerol, or esters of fatty alcohols with low C-alkanoic acids or with fatty acids;

- Silicone oils such as dimethylpolysiloxanes, diethylpolysiloxanes, diphenylpolysiloxanes and mixed forms thereof.

The oil phase of the emulsions, oleogels or hydrodispersions or lipodispersions in the context of the present invention is advantageously selected from the group of esters of saturated and / or unsaturated, branched and / or unbranched alkanecarboxylic acids having a chain length of 3 to 30 carbon atoms and saturated and / or or unsaturated, branched and / or unbranched alcohols having a chain length of 3 to 30 carbon atoms, from the group of esters of aromatic carboxylic acid and saturated and / or unsaturated, branched and / or unbranched alcohols having a chain length of 3 to 30 carbon atoms. Such ester oils can then be advantageously selected from the group isopropyl myristate, isopropyl palmitate, isopropyl stearate, isopropyl oleate, n-butyl stearate, n-hexyl laurate, n-decyl oleate, isooctyl stearate, isononyl stearate, isononyl isononanoate, 2-ethylhexyl palmitate, 2-ethylhexyl laurate, 2-hexadecyl stearate, 2-octyl dodecyl palmitate, oleyl oleate, oleyl erucate, erucyl oleate, erucyl erucate and synthetic, semi-synthetic and natural mixtures of such esters, e.g. B. jojoba oil.

Furthermore, the oil phase can advantageously be selected from the group of branched and unbranched hydrocarbons and waxes, silicone oils, dialkyl ethers, the group of saturated or unsaturated, branched or unbranched alcohols, and fatty acid triglycerides, namely the triglycerol esters of saturated and / or unsaturated, branched and / or unbranched alkanecarboxylic acids of a chain length of 8 to 24, in particular 12-18 C-atoms. The fatty acid triglycerides can be selected, for example, advantageously from the group of synthetic, semi-synthetic and natural oils, for. For example, olive oil, sunflower oil, soybean oil, peanut oil, rapeseed oil, almond oil, palm oil, coconut oil, palm kernel oil and the like.

Any mixtures of such oil and wax components are also advantageous to use in the context of the present invention. It may also be advantageous, if appropriate, to use waxes, for example cetyl palmitate, as the sole lipid component of the oil phase.

Advantageously, the oil phase selected from the group 2-Ethylhexyliso- stearate, octyldodecanol, isotridecyl isononanoate, isoeicosane, 2-ethyl hexylcocoat, C ₂ -i ₅ alkyl benzoate, caprylic-capric acid triglyceride, Dicap- rylether.

Particularly advantageous are mixtures of Ci ₂ -i ₅ -A! Alkyl benzoate and

2-ethylhexyl isostearate, mixtures of C ₂ - ₁₅ -alkyl benzoate and decylisononanoat Isotri¬ and mixtures of C] ₂ -i ₅ alkyl benzoate, 2-ethylhexyl isostearate and isotridecyl isononanoate.

Of the hydrocarbons, paraffin oil, squalane and squalene are to be used advantageously in the context of the present invention. Advantageously, the oil phase may also contain a content of cyclic or linear silicone oils or consist entirely of such oils, although it is preferred, in addition to the silicone oil or silicone oils, an additional content of other.

To use oil phase components. 5

Advantageously, cyclomethicone (octamethylcyclotetrasiloxane) is used as the silicone oil to be used according to the invention. However, other silicone oils are also advantageous for the purposes of the present invention, for example Hexamethylcyclotrisiloxan, -J O polydimethylsiloxane, poly (methylphenylsiloxane).

Furthermore, mixtures of cyclomethicone and isotridecyl isononanoate, of cyclomethicone and 2-ethylhexyl isostearate, are particularly advantageous

According to the invention, preferred dispersions are used as or are paints or lacquers, cosmetic or pharmaceutical preparations or cleaning or coating compositions.

Thus, cosmetic formulations containing silica particles and / or silica-coated particulate UV filters and / or silica-shredded UV filters are a preferred subject of the present invention. The corresponding materials have already been described above.

Other dispersions which are likewise preferred according to the invention are coatings which are curable with infrared radiation and contain antimony tin oxide particles 5. Examples of such particles are the products sold under the trade name Minatec (Merck).

Suitable dispersants here include polymers, in particular thermoplastics such as PE, PP, PVC, PMMA, PS, ABS, polyester, polyamides. The dispersion can be advantageous over thermal processes (extruding, kneading) or using solutions of these polymers in suitable solvents.

The following examples are intended to illustrate the invention without limiting it.

Beispielβ

Example 1: Synthesis of a random copolymer of dodecyl methacrylate (lauryl methacrylate; LMA) and hydroxyethyl methacrylate (HEMA).

Diθ molecular weight control can be achieved by adding mercaptoethanol.

There are LMA and HEMA, presented in an amount corresponding to the table below 1, in 12 g of toluene and 300 mg of mercaptoethanol and radical-polymerized under argon at 7O ⁰ C after start of the reaction by the addition of 100 mg of AIBN in 1 mL of toluene for 18h. By subsequent initiation with a further 50 mg of AIBN in 1 ml of toluene and further reaction for 12 h, unreacted residual monomer is likewise polymerized. Thereafter, the solvent is removed under reduced pressure and the resulting polymer is dried. The characterization of the resulting polymers is shown in Table 1.

Table 1: Amounts used of monomers and characterization of the resulting polymers

Example 2: Dispersion of SiO ₂ particles

800 mg of the polymer from Example E2 are dissolved in 20 g of paraffin oil! solved. With the introduction of 10 g of silica particles (Monospher 1000, Merck, average particle size 1 micron) with stirring (2-blade Rüherer, 200 / min, no appreciable increase in viscosity) produces a stable dispersion.

Example 3: Dispersion of SiO ₂ -coated TiO ₂ particles

800 mg of the polymer from Example E2 are in 20 g of cosmetic

Oil (Miglyol® 8810 N; Fa Condea; INCI: Butylene Glycol DiCarprylate / Dicaprate). The addition of 10 g of Eusolex® T-AVO (Merck) with stirring (2-sheet Rüherer, 200 / min) produces a stable dispersion.

Example 4: Dispersion of SiO ₂ -coated TiO ₂ particles

Containing a dispersion

6% by weight of the polymer from Example E2 57% by weight Miglyol 8810 N (Condea)

37% by weight of Eusolex® T-AVO (Merck) is homogenized with a dispersing disk and then for about 5 minutes with a U-Turax (at 8000 rpm). After one day of service life, the viscosity is about 12500 mPa s.

Example 5: Dispersion of Antimony Tin Oxide Particles

800 mg of the polymer from Example E2 are dissolved in 20 g of terpineol. When 20 g of antimony tin oxide particles (Minatec.RTM., Merck) are added with stirring (2-blade Rüherer, 200 rpm, no appreciable increase in viscosity), a stable dispersion is formed. Example 6 Production of Redispersible Nanoscale Antimony Tin Oxide Particles

1 g of the polymer from Example E2 are dissolved in 100 g of toluene Darin 10 g of a stable aqueous dispersion of antimony-tin oxide particles (Minatec®, Fa. Merck), solids content 2g, emulsified (U-Turrax, ultrasound). The solvent mixture is removed. Hydrophobized particles are obtained which are very readily redispersible in organic solvents (for example toluene).

Example 7 Dispersion of Fumed Silica

800 mg of the polymer from Example E2 are dissolved in 20 g of toluene. The entry of 10 g fumed silica (Aerosil ^® 50OX;. Degussa) while stirring (2-sheet Rüherer; 200 / min; no significant increase in viscosity) creates a stable dispersion.

Claims

claims

1. Use of random copolymers comprising at least one structural unit having hydrophobic radicals and at least one structural unit having hydrophilic radicals as dispersants for the preparation of dispersions with incompatible disperse and continuous phase.

2. Use of random copolymers comprising at least one structural unit having hydrophobic radicals and at least one structural unit having hydrophilic radicals as

Dispersant for dispersing particles with a hydrophilic surface in oils.

3. Use according to at least one of claims 1 or 2, characterized in that the hydrophilic particles have a metal (hydr) oxide surface, wherein the metal (hydr) oxide is preferably selected from oxides or hydroxides of silicon, aluminum, magnesium , Antimony, cerium, cobalt, chromium, indium, nickel, zinc, titanium, iron, yttrium, tin, zirconium, and mixtures thereof.

4. Use according to at least one of the preceding claims, characterized in that the particles are silica particles or silica-coated particles.

5. Use according to at least one of the above

Claims, characterized in that the dispersant in a concentration of 0.5 to 80 wt .-%, preferably in a concentration of 1 to 50 wt .-% and particularly preferably in a concentration of 2 to 8 wt .-%, based on the entire dispersion is used.

6. Use according to at least one of the above

Claims, characterized in that the particles with hydrophilic surface in a weight fraction of 1 to 90% by weight, preferably 10 to 60 wt .-%, based on the dispersion, are dispersed.

7. Use according to at least one of the preceding claims, characterized in that at least one further dispersant and / or dispersing aid is used.

8. Use according to at least one of the preceding claims, characterized in that the weight ratio of structural units having hydrophobic radicals to structural units having hydrophilic radicals in the random copolymers in the range 1: 10 to 500: 1, preferably in the range 1: 2 to 100: 1 and especially preferably in the range 1: 1 to 10: 1.

9. Use according to at least one of the preceding claims, characterized in that the weight-average molecular weight of the random copolymers in the range of M _w = 1000 to 1 000 000 g / mol, preferably in the range of

2,000 to 50,000 g / mol.

10. Use according to at least one of the preceding claims, characterized in that the copolymers substantially correspond to the formula I, wherein

X and Y are the radicals of conventional nonionic or ionic

Correspond to monomers and

R ¹ is hydrogen or a hydrophobic side group, preferably selected from the branched or unbranched alkyl radicals having at least 4 carbon atoms in which one or more, preferably all H atoms can be replaced by fluorine atoms, and

R ² is a hydrophilic side group which preferably has one or more phosphonate, phosphate, phosphonium, sulfonate, sulfonium, (quaternary) amine, polyol or polyether radicals, more preferably one or more hydroxyl radicals means that the respective groups are randomly distributed in the polymer, and within a molecule -XR ¹ and -YR ^{2 may} each have several different meanings and the copolymers in addition to the structural units shown in formula I further structural units, preferably those without or with short Side chains such as Ci _-4 alkyl may contain.

11. Use according to claim 10, characterized in that X and Y independently of one another represent -O-, -C (= O) -O-, -C (= O) -

NH-, - (CH ₂ ) n-, phenylene or pyridyl.

12. Use according to at least one of claims 10 or 11, characterized in that at least one structural unit of the copolymer contains at least one quaternary nitrogen or Phospheratom, wherein R ^{2 is} preferably a

Side group - (CH ₂₎ m- (N ⁺ (CH3) 2) - (CH 2) n SO ₃ ^"or a pendant group - (CH ₂₎ _m - (N ⁺ (CH3) 2) - (CH ₂₎ n- Pθ 3 ² -, - (CH ₂ ) _m - (N ⁺ (CH ₃ ) 2) - (CH ₂ ) nO-PO 3 ^{2 "} or a side group - (CH ₂ Jm- (P ⁺ (CH ₃ ) 2) - ( CH ₂ ) _n -SO ₃ ^' , where m is an integer from the range of 1 to 30, preferably from the range 1 to 6, particularly preferably 2, and n is an integer from the range of 1 to 30 , preferably from the range 1 to 8, particularly preferably 3.

13. Use according to any one of claims 1 to 11, characterized in that as a random copolymer

Copolymer consisting essentially of lauryl methacrylate (LMA) and hydroxyethyl methacrylate (HEMA) is used.

14. Use according to at least one of claims 1 to 12, characterized in that at least one structural unit of the copolymer is an oligo- or polymer, preferably a macromonomer, with polyethers, polyolefins and polyacrylates being particularly preferred as macromonomers.

15. Use according to at least one of claims 1 to 12 or 14, characterized in that at least one structural unit of the copolymer has a phosphonium or sulfonium radical

, _{| Q} has.

16. Use according to at least one of the preceding claims, characterized in that in the random copolymers in addition to the at least one structural unit having hydrophobic radicals and the at least one structural unit with

15 hydrophilic residues further structural units, preferably without such hydrophilic or hydrophobic side chains or with short side chains, such as _C-4 alkyl ι_ are included.

17. Oily dispersion containing hydrophilic particles, characterized in that at least one dispersant

²⁰ random copolymer containing at least one

Structural unit with hydrophobic residues and at least one structural unit with hydrophilic radicals is included.

18. Dispersion according to claim 17, characterized in that the

Dispersants in a concentration of 0.5 to 80 wt .-%,

25 is preferably present in a concentration of 1 to 50 wt .-% and particularly preferably in a concentration of 2 to 8% by weight, based on the total dispersion.

19. dispersion in according to at least one of the preceding claims, _™ that the hydrophilic particles have a

Have metal (hydr) oxide surface, wherein the metal (hydr) oxide is preferably selected from oxides or hydroxides of Silicon, aluminum, magnesium, antimony, cerium, cobalt, chromium, indium, nickel, zinc, titanium, iron, yttrium, tin, zirconium and mixtures thereof, wherein the particles are particularly preferably silica particles or silica-coated particles , 5

20. A dispersion according to at least one of the preceding claims, characterized in that the particles having a hydrophilic surface in a weight fraction of 1 to 90 wt .-%, preferably 10 to 60 wt .-%, based on the dispersion,

^ Q exist.

21. Dispersion according to at least one of the preceding claims, characterized in that the dispersion is a cosmetic preparation containing silica particles and / or silica-coated particulate UV filters.

15

22. A dispersion according to any one of claims 17 to 20, characterized in that the dispersion is an infrared-curable lacquer containing antimony tin oxide particles.

23. Process for the preparation of an oily dispersion of hydrophilic particles, characterized in that random copolymers comprising at least one structural unit having hydrophobic radicals and at least one structural unit having hydrophilic radicals are mixed with an oil and hydrophilic particles.

25

24. A process for the preparation of an oily dispersion according to claim

23, characterized in that the random copolymers are presented in an oil, and then the hydrophilic particles are added.

_O0 25. A process for the preparation of an oily dispersion according to claim 23, characterized in that an aqueous dispersion of hydrophilic particles with a solution of a statistical

Copolymers are mixed (emulsified) in a hydrophobic solvent and the water or both solvents are removed.

26. Process for the preparation of an aqueous dispersion of hydrophobic particles, characterized in that random copolymers comprising at least one structural unit having hydrophobic radicals and at least one structural unit having hydrophilic radicals are mixed with water and hydrophobic particles.

10

27. Process for the preparation of an aqueous dispersion according to

Claim 26, characterized in that the random copolymers are initially introduced in water, and then the hydrophobic particles are added.

15. Powder composition containing hydrophilic particles, characterized in that the hydrophilic particles are coated with at least one random copolymer containing at least one structural unit having hydrophobic radicals and at least one structural unit having hydrophilic radicals.

20 29. A powder composition according to claim 28, characterized in that the hydrophilic particles have a metal (hydr) oxide surface, wherein the metal (hydr) oxide is preferably selected from oxides or hydroxides of silicon, aluminum, magnesium antimony, cerium , Cobalt, chromium,

Indium, nickel, zinc, titanium, iron, yttrium, tin, zirconium and

25

Mixtures thereof, wherein the particles are particularly preferably silica particles or silica-coated particles.

30. A powder composition according to at least one of the preceding claims _on that

Particles with a hydrophilic surface in a weight fraction of 20 to 95 wt .-%, preferably 30 to 80 wt .-%, based on the powder composition.

31. Powder composition according to at least one of the preceding claims, characterized in that the hydrophilic particles are substantially silica particles and / or silica-coated particulate UV filter, in particular silica-coated Titaπdioxid are.

32. The powder composition according to claim 28, wherein the hydrophilic particles are essentially antimony tin oxide particles.

33. A process for the preparation of a powder composition, characterized in that a dispersion according to any one of claims 23 to 27 is prepared and then the solvent is removed.

34. A process for the preparation of a dispersion, characterized in that a powder composition according to any one of claims 28 to 32 is mixed with at least one oily carrier material.