WO2013004659A1

WO2013004659A1 - Process for modifying particulate solids by photopolymerization

Info

Publication number: WO2013004659A1
Application number: PCT/EP2012/062830
Authority: WO
Inventors: Rainer Jordan; Timo KORFMANN
Original assignee: Wacker Chemie Ag
Priority date: 2011-07-04
Filing date: 2012-07-02
Publication date: 2013-01-10
Also published as: DE102011078613A1

Abstract

Process for preparing particulate finely divided solids having a modified surface, characterized in that a vinylic monomer of the general formula (I): (R¹ _aR¹ _bC=CR¹ _cR¹ _d) is dispersed with a particulate finely divided solid having a large surface area to form a mixture, where the particulate finely divided solid having a large surface area has been silylated by treatment with silanes of the general formula (II): X_1+x'-SiR⁴ _2-x'-(CH₂)_v-Y, alone or in any mixtures, and this mixture is reacted by means of free-radical polymerization by input of radiation.

Description

Process for the modification of particulate solids

photopolymerization

The invention relates to a process for the modification of particulate solids by photopolymerization, the modified particulate solids thus obtained and their use.

The use of finely divided particulate solids having a high specific surface area as reinforcing fillers in organic and organosilicon elastomers for improving the mechanical properties, such as tear propagation resistance, moduli, and elongation is known. The use of finely divided particulate solids to improve the mechanical properties of crosslinked thermosets, such as epoxy resins, is known. By adding particles to the duromer matrix, their mechanical properties such as scratch resistance, tensile strength, flexural strength, compressive strength, modulus of elasticity or impact strength can be improved.

The use of finely divided particulate solids to improve the mechanical properties of thermoplastics such as polystyrenes, polyacrylates, polyethylenes, polypropylenes and others is known. By the addition of

Particles to the thermoplastic matrix can improve their mechanical properties such as scratch resistance, tensile strength, flexural strength, compressive strength, modulus of elasticity or impact resistance. Furthermore, the dimensional stability of thermoplastics-based materials at elevated temperature is improved by the addition of particulates, ie the cold flow is reduced. Usually, surface-modified, ie hydrophobic, reinforcing fillers are used. The aim of the surface modification or hydrophobing is inter alia the improvement of the Einmxschbarkeit the fillers in the polymeric matrix. The surface modification can be carried out ex-situ, ie before mixing in of the particles, or in-situ, ie the polymer modifier is added to the corresponding modifier and the unmodified particles are subsequently mixed in, so that the particles are surface-modified during the mixing and compounding process ,

From US20060160916 the surface modification u.a. of particulate solids by free radical polymerization. The surfaces to be modified are treated with an amine photoinitiator prior to the polymerization and, if appropriate, an additional photosensitizer is added. The use of aminic photoinitiators is problematic, especially with regard to the danger of a later discoloration of the radically modified surfaces by N-oxide formation.

The fillers are preferably chemically irreversibly modified. That the modifier is chemically attached to the particle surface. Typical modifiers that chemically react with the particle surface are organosilanes. These form stable filler-silicon-oxygen bonds with the filler surface.

The choice of the surface modifier depends on the chemical structure of the polymer matrix in which the filler is to be used. Usually, surface modifying agents are used which have good compatibility, ie miscibility with the polymer matrix, in order to achieve a good dispersion. persion, ie to ensure distribution of the filler particles,

The object of the invention was to provide a process for the preparation of particulate finely divided solids having a modified surface.

This object is achieved by a process in which a vinylic monomer of the general formula (I)

{R ¹ _e R ¹ bC = CR ¹ _c R ¹ _d ) where

1

R is the same or different and is hydrogen, or optionally substituted with -CN, -NCO, -NR ² ₂ , -GOOH, -COOR ² , -halogen, -acrylic, -epoxy, -SH, -OH or -CONR ² ₂ substituted C-linked Ci-C2o ~ ^K ° hlenwasserstoff est, preferably a C ^ -CQ-

Hydrocarbon radical, particularly preferably a Ci-C3 ~

Hydrocarbon radical, or an aryl radical, or a heteroaryl radical such as pyridyl radical, or a C _] _Cj_5-Kohlenwasserstoffoxyrest, preferably a C] _Cg hydrocarbonoxy radical, particularly preferably a C1-C4 hydrocarbonoxy radical, in each of which one or more, non-adjacent methylene units can be replaced by groups -O-, -CO-, -C0O ~, -OCO-, or -OCOO-, -S-, or - NR ² - and in which one or a plurality of mutually non-adjacent methine units can be replaced by groups, -N =, or - P =, or a heteroatom such as chloride, bromide, ~ NR ² ₂ , or a C-linked carboxylic acid group -COOH, or C-bonded carboxylate Group -COO ^" , or C-linked ester group -COOR ² , or aldehyde group -CHO, or keto group -C {O) R ² , o- of O-bonded carboxylate group -OOCR ² , and

R ^{2 is the} same or different and is hydrogen or a optionally substituted hydrocarbon radical or aryl radical,

where a, b, c, d = 0, 1 or 2, with the proviso that a + b = 2 and c + d = 2

with a particulate finely divided solid with large

Surface is dispersed to a mixture, wherein the particulate finely divided solid with high surface area by treatment with silanes of the general formula (II) X _{1 + x} -SiR ⁴ ₂ _ _x , - (CH ₂ ) _V -Y (II), alone or is silylated in any mixtures, wherein

X is halogen, nitrogen radical, OR ³ , OCOR ³ and

R ^{3 is} a C ~ 0 bonded C] _ Ci5 hydrocarbon radical, preferably a Ci-Cg hydrocarbon radical, more preferably a C _] _C3 hydrocarbon radical, or an acetyl radical, and

R ^{4 is} a hydrogen atom or optionally with -CN,

-NCO, -NR ² ₂ , -COOH, -COOR ² , -halo, -acryl, -epoxy, -SH, -OH or -COMR ² 2 substituted Si-C bonded C 1 -C 20 -hydrocarbon est, preferably a Cg hydrocarbyl ~ radical, particularly preferably a _C] _-C3 hydrocarbon radical, or an aryl group, or Ο -Ο 5 -Kohlenwasserstoffoxyrest, preferably a _C] _-Cg hydrocarbonoxy radical, particularly preferably a Ci- C ~ Kohlenwassersto foxy radical, in each case one o ~ the several, not adjacent methylene units by

Groups -O-, -CO-, -COO-, -OCO-, or -OCOO-, ~S-, or -NR ² - may be substituted and in which one or more mutually non-adjacent methine units are represented by groups, -N = or -P = can be replaced, is and

Y is hydrogen, unsaturated or mono- or polyunsaturated C ₁ -C _2Q- hydrocarbon radical, -OC (O) C (R) = CH ₂ (R = H, Cx-C5-hydrogen radical, preferably a C ^ -Q-

Hydrocarbon radical, particularly preferably a C -C3-

Kohlenwasserstof radical f) -vinyl, -hydroxyl, -halogen, phosphoric phonato, -NCO, ~ NH-C (0) -OR {R = C ₁ -C ₁₅ - Hydrocarbon ^"radical, preferably a Ci-Cs Hydrocarbon radical, particularly preferably a C 1 -C 3 -hydrocarbon radical), -glycidoxy, -SH, acid anhydrides such as succinic anhydride

and v = 0 to 10, preferably 0 to 5 and more preferably 0, 1, or 3, and x '= 1 or 2

and this mixture is reacted by the use of radiation by means of radical polymerization.

It has been astonishing and in no way foreseeable for a person skilled in the art that fillers with a thick polymer layer which have excellent incorporability in thermoplastics can be obtained by a direct reaction of silylated fillers with vinylic monomers in a free-radical polymerization. Particularly preferred compounds of the formula I are used

2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, methyl methacrylate, methacrylic acid (MMA), acrylic acid, glycidyl acrylate, 2- {dimethylamino} ethyl methacrylate, ethylene glycol dimethacrylate,

3- (acryloyloxy) -2-hydroxypropyl methacrylate, styrene, 4-vinylpyridine (4-VP).

In the process according to the invention, preference is given to using a solid having an average particle size of less than 100 μm, in particular preferably having an average primary particle particle size of from 5 to 100 nm. These primary particles can not exist in isolation, but are components of larger aggregates and agglomerates. Suitable solids are metal oxides, silicates, aluminates, titanates, or aluminum phyllosilicates, such as bentonites, such as montmorillonite, or smectites or hectorites. Preferred solids are metal oxides. Preferably, the metal oxide has a specific surface area of preferably 0.1 to

1000 m ² / g (measured according to the BET method according to DIN 66131 and 66132), particularly preferably from 10 to 500 m ² / g, very particularly preferably from 30 to 450 m ² / g. For the purposes of the present invention, the abovementioned definitions are also the preferred definition of a large specific surface area.

The metal oxide may have aggregates (definition according to DIN 53206) preferably in the range of diameters of 100 to 1000 nm, the metal oxide comprising aggregates comprising agglomerates (definition according to DIN 53206} which depends on the external shear stress (eg due to the Measuring conditions) sizes of 1 to 1000 μτη may have.

For technical reasons, the metal oxide is preferably an oxide with a covalent bond moiety in the metal-oxygen bond, preferably an oxide of the main and subgroup elements, such as boron, aluminum, gallium or Indium oxide, or the 4th main group such as silica, germanium dioxide, or tin oxide or dioxide, lead oxide or dioxide, or an oxide of the 4th subgroup, such as titanium dioxide, zirconium oxide, or hafnium oxide. Other examples of suitable metal oxides are stable nickel, cobalt, iron, manganese, chromium or vanadium oxides.

Particularly preferred metal oxides are aluminum (III), titanium (IV) and silicon (IV) oxides, such as, for example, produced by wet chemistry. te, for example, precipitated silicas or silica gels, or produced in processes at elevated temperature aluminas, titanium dioxides or silicas, such as pyrogenic aluminas, titanium dioxides or silicas or silica.

Especially preferred as the metal oxide is fumed silica, which in a flame reaction preferably consists of organosilicon compounds, e.g. of silicon tetrachloride or methyldichlorosilane, or hydrogentrichlorosilane or hydrogenmethyldichlorosilane, or other methylchlorosilanes or alkylchlorosilanes, also in mixture with hydrocarbons, or any volatilizable or sprayable mixtures of organosilicon compounds, as mentioned, and hydrocarbons, e.g. in a hydrogen-oxygen flame, or even a carbon monoxide-oxygen flame, is produced. The preparation of the silica can be carried out optionally with and without additional addition of water, for example in the step of purification; preferred is no addition of water.

Preferably, the fumed silica has a fractal surface dimension of preferably less than or equal to 2.3, more preferably less than or equal to 2.1, most preferably from 1.95 to 2.05, the fractal dimension of the surface being D _s is defined as:

Particle surface A is proportional to the particle radius R high D _s

The fractal dimension of the surface was determined by small-angle X-ray diffraction {SAXS).

Preferably, the silica has a fractal dimension of mass D _m of preferably less than or equal to 2.8, preferably equal to or greater than 2.7, more preferably from 2.4 to 2.6 on. The fractal dimension of the mass D _m is defined as:

Particle mass M is proportional to the particle radius R high ^D ra.

The fractal dimension of the mass was determined by means of small-angle X-ray diffraction (SAXS).

The silylated particulate solids can be prepared in continuous or batch processes, the silylation process can be made up of one or more steps. Preferably, the silylated solids are prepared by a process in which the manufacturing process is carried out in separate steps: (A) first producing the non-silylated solids, then (B) silylating the solid with (1) loading the solid with silane of the general formula II, {2} reaction of the solid with the silane of the general formula II and (3) purification of the solid of excess silane of the general formula II.

The surface treatment is preferably carried out in an atmosphere which does not result in the oxidation of the silylated solid, i. preferably less than 10% by volume of oxygen, more preferably less than 2.5% by volume. Best results are achieved with less than 1% oxygen by volume.

Assignment, reaction and purification can be carried out as a batch or continuous process. For technical reasons, preferred is a continuous Reaktionsfüh- tion.

The coating is preferably carried out at temperatures of -30-250 ° C., preferably 20-150 ° C., particularly preferably 20-80 ° C. Preferably, the occupation step is cooled to 30-50 ° C.

The residence time is 1 min - 24 h, preferably 15 min to 240 min, for reasons of space-time yield particularly preferably 15 min to 90 min.

The pressure in the occupancy ranges from weak negative pressure to 0.2 bar to overpressure of 100 bar, for technical reasons normal pressure, that is pressure-free working against external / atmospheric pressure is preferred. For the silylation of the particulate, finely divided solid with a high surface area, the silanes of the general formula II can be synthesized, alone or in any desired mixtures with organosiloxanes, from units of the formula

(R / siOaa), and / or

can be used, wherein the number of these units in an organosiloxane is at least 2, and the radicals R ^{1 may be the} same or different and have the meaning given. The organosiloxanes are preferably liquid at the temperature of use.

Examples of organosiloxanes are linear or cyclic dialkylsiloxanes having an average number of dialkylsiloxy units of greater than 2, preferably greater than 5.

The dialkylsiloxanes are preferably dimethylsiloxanes.

Examples of linear polydimethylsiloxanes are those having the terminal groups: trimethylsiloxy, dimethylhydroxysiloxy, dimethylchlorosiloxy, methyldichlorosiloxy, dimethylmethoxysiloxy, methyldimethoxysiloxy, dimethylethoxysiloxy, methyldiethoxysilyl, dimethylacethoxysiloxy, methyldiacethoxysiloxy; Particularly preferred are trimethylsiloxy and Hylhydroxysiloxy.

The end groups can be the same or different. The silane of the general formula II is preferably used as liquid added added and in particular the powdered metal oxide.

This is preferably done by nozzle techniques, or similar techniques, such as effective atomization techniques, such as atomizing in 1-fluid nozzles under pressure (preferably 5 to 20 bar), spraying in 2-fluid nozzles under pressure (preferably gas and liquid 2-20 bar), ultrafine distribution with Atomizers or gas-solid exchange units with movable, rotating or static internals, which allow a homogeneous distribution of the silane with the powdered metal oxide.

Preferably, the silane of the general formula II is added as a finely divided aerosol, the aerosol preferably having a sinking rate of 0.1-20 cm / s and a droplet size having an aerodynamic particle radius of 5-25 .mu.m.

Preferably, the loading of the solid and the reaction with the silane of the general formula II takes place under mechanical or gas-borne fluidization. Particularly preferred is the mechanical fluidization.

A gas-supported fluidization can be carried out by all inert gases that do not react with the silane of the general formula II, the solid, and the silylated solid, so do not lead to side reactions, degradation reactions, oxidation processes and flame and explosion phenomena, as preferential N2, Ar, other noble gases, CO2, etc. The supply of the gases for fluidization is preferably in the range of Leerrohrgas- speeds of 0.05 to 5 cm / s, more preferably from 0.5 to 2.5 cm / s.

Particularly preferred is the mechanical fluidization, which takes place without additional gas addition beyond the inertization, by paddle stirrer, anchor agitator, and other suitable stirring elements.

In a particularly preferred embodiment, non-exhaustive recycled silane of the general formula II and exhaust gases from the purification step back into the step of loading and loading of the solid; this can be done partially or completely, preferably to 10-90% of the total volume flow of gas volumes leaving the purification.

This happens in suitably tempered devices.

This recycling is preferably carried out in non-condensed phase, ie as gas or as vapor. This recycling can be carried out as mass transfer along a pressure equalization or as controlled material transport with the technically usual systems of gas transport, such as fans, pumps, compressed air membrane pumps. Since the return of the non-condensed phase is preferred, the heating of the returning lines is recommended if appropriate.

The recycling of the unreacted silane of the general formula II and of the exhaust gases can be between 5 and 100% by weight, based on their total mass, preferably between 30 and 80% by weight. The recycling may be, based on 100 parts of freshly used silane of the general formula II, between 1 and 200 parts, preferably 10 to 30 parts.

The return of the Abreinigungprodukte the Silylierreaktxon in the occupancy is preferably carried out continuously.

The silylation is preferably carried out at temperatures 40-400 ° C, preferably 40-350 ° C and more preferably at 80-300 ° C.

The reaction time is 5 minutes to 48 hours, preferably 10 minutes to 5 hours.

Optionally, protic solvents may be added, such as liquid or volatilizable alcohols or water; typical alcohols are iso-propanol, ethanol and methanol. It is also possible to add mixtures of the abovementioned protic solvents. Preferably, 1 to 50% by weight of protic solvent, based on the solid, are added, in particular preferably 5 to 25%. Particularly preferred is water.

Alternatively, acidic catalysts of acidic character in the sense of a Lewis acid or a Brönsted acid, such as hydrogen chloride or basic catalysts, of a basic character, in the sense of a Lewis base or a Brönsted base, such as ammonia, may be added. Preferably, these are added in traces, i.e. less than 1000 ppm. Most preferably, no catalysts are added.

The cleaning takes place at a purification temperature of 20 to 200 ° C, preferably 50 ° C to 150 ° C, more preferably from 50 to 120 ° C.

The cleaning step is preferably characterized by movement, with slow movement and low mixing being particularly preferred. The stirrers are advantageously adjusted and moved so that preferably a mixing and fluidizing, but not complete turbulence, occurs.

The cleaning step may be further characterized by increased gas input, corresponding to a Leerrohrgasgeschwindig- speed of 0.001 to 10 cm / s, preferably 0.01 to 1 cm / s. This can be done by any inert gases that do not react with the silane of the general formula II, the solid, and the silylated solid, so do not lead to side reactions, degradation reactions, oxidation processes and flame and explosion phenomena, such as preferably N2, Ar, other noble gases , CO2, etc.

The surface-modified particulate solids used with particular preference in the process according to the invention have a carbon content of greater than 0.1% by weight, preferably from 0.5 to 20% by weight and more preferably from 1 to 15% by weight, in each case based on 100 m ² / g specific surface, ie at lower or higher specific surface are obtained correspondingly linear lower or higher values.

The surface-modified particulate solids used particularly preferably in the process according to the invention have a content of extractable components of less than 20

% By weight, preferably less than 18% by weight and more preferably less than 15% by weight.

Extractable components in this context are preferably to be understood as meaning components which are separated by means of organic solvents, such as e.g. Extract the THF or toluene extractively from the particle surface and remove it by analytical methods, e.g. Quantify elemental analysis or other methods. The proportion of particulate solid which has been dispersed in the vinylic monomer of the general formula (I) is preferably from 0.1 to 50% by weight, preferably from 0.1 to 25% by weight and more preferably from 0.5 to 15% by weight. The dispersion can be done e.g. by stirring by means of preferably fast-running stirrers such as dissolvers, rotor-stator systems, or by treatment with ultrasound such as ultrasonic baths or sonotrodes.

The dispersion is preferably carried out over a period of 10 seconds to 2 hours.

Optionally, inert solvents are added. The inert solvents are preferably organic solvents such as hydrocarbons, such as pentane or hexanes, or ethers, such as diethyl ether or THF, or aroaromatic solvents, such as toluene.

The inert solvents are preferably used in proportions of 70% to 99% based on the particulate solid. A photosensitizer-free reaction mixture is preferably used, ie the reaction mixture contains no photosensitizer such as benzophenone. As radiation is preferably electromagnetic radiation, preferably electromagnetic radiation in a wavelength range of 1 nm to 10,000 nm, such as light radiation in the visible range of about 400 nm - 800 nm, or UV radiation having a wavelength range of 1 nm to 400 nm, preferably 100 nm to 400 nm and particularly preferably 180 - 380 nm used.

Further, electron beams such as X-rays or cathode rays can be used.

One or more radiation sources, e.g. Lamps are used. The radiation source (s) may be introduced into the reaction mixture in the form of a submersion source or externally, i. act on the mixture above the mixture or through the wall of the reaction vessel. Preference is given to an external effect.

In this case, the process according to the invention is carried out in a reaction vessel which consists of an inert material, preferably by means of suitable devices, e.g. radiation-permeable window, permeable to the radiation used. In this case, the reaction vessel is preferably made of glass with an adsorption minimum in the range of the radiation source used.

The duration of action of the radiation is preferably 10 seconds to 48 hours, more preferably 60 seconds to 48 hours, particularly preferably 30 minutes to 24 hours.

Preferably, the mixture is cooled during the photopolymerization. The temperature of the reaction mixture during the pho- topolymerization is - 20 ° C to 100 ° C, preferably -20 ° C to 50 ° C, more preferably 0 ° C to 40 ° C.

Preferably, the mixture is stirred during the photopolymerization.

After completion of the photopolymerization, the excess monomer is removed. This can be done by condensation in vacuo or filtration. Preference is given to condensing off in vacuo.

Subsequently, the obtained particulate solids with attached polymer layer by adhering to a suitable solvents, preferably an organic solvent such as toluene, THF, an alcohol such as methanol or ethanol, a chlorinated hydrocarbons such as dichloromethane, hydrocarbons such as pentane, hexenes or higher boiling hydrocarbons of adhering monomers or not chemically bonded to the particulate solids polymers. By means of the method according to the invention, a particulate surface-modified solid is provided which has good compatibility in thermoplastics, such as, for example, polystyrene, polyethylene, polypropylene, polyacrylates, such as polymethyl methacrylate.

This particulate, finely divided solid with a large specific surface area is modified on its surface with a polymer layer consisting of monomers of the general formula III,

- (^ _b C-CR ¹ ^) - (in) where Rl is the same or different and has the meaning given to formula I. The particulate solid according to the invention with attached polymer layer preferably has a carbon content of greater than 0.1% by weight, preferably from 0.5 to 75% by weight, particularly preferably from 1 to 50% by weight, and very particularly preferably from 1 to 25% by weight %, in each case based on 100 ra ² / g specific

Surface, i. with lower or higher specific surface area correspondingly linear lower or higher values are obtained. The particulate solids according to the invention with attached polymer layer preferably have a content of extractable components of less than 20% by weight, preferably less than 15% by weight and more preferably less than 10% by weight. The information on suitable / preferred particulate solids and their properties correspond to the details given for the process according to the invention.

The metal oxide particles according to the invention can be used to improve the mechanical properties such as scratch resistance, tensile strength, flexural strength, compressive strength, modulus of elasticity or impact resistance of e.g. Thermoplastics such as polystyrenes, polyacrylates, polyethylenes, polypropylenes are used. Further, particulate addition can improve the dimensional stability of thermoplastics based materials at elevated temperature, i. the cold flow can be reduced.

The metal oxide particles according to the invention can be used for the production of composites based on, for example, thermoplastics such as polystyrenes, polyacrylates, polyethylenes, polypropylenes or others.

The following examples serve to further explain the invention. Examples

General Experimental Description: 100 mg of silica according to Table 1 were placed in a 10 mL photoreaction tube and dried in vacuo for several hours. Subsequently, 6 mL of distilled monomer according to Table 2 was added and degassed by 3 freeze / thaw cycles. The suspension was then irradiated with UV light (Amax = 350 nm) at room temperature for several hours (see Table 2). Remaining monomer and resulting homopolymer in solution are filtered through a high-pressure filtration device through a Teflon filter (pore size: 1.2 pm). The filtrate was washed 5 times with 20 mL of a good solvent for the corresponding polymer {polystyrene in toluene; Polymethyl methacrylate (PMMA) in acetone, poly-4-vinylpyridine (P4VP) in ethanol) and dried in vacuo. A white powder with the analytical data as shown in Table 2 was obtained. Table 1: Description of the surface-modified fumed silicas used

spec. Silane surface mass loss

Designation Surface modification TGA ^' EA m2 / g (%) (% C)

Silica 1 200 trimethylsiloxy-2, 83 2, 67

Silica 2 200 octyltrimethoxy 5.03 4.69

Silica 3 200 hexadecyltrimethoxy 9, 95 10, 28

Silica 4,200 Phenyltrimethoxy 5, 94 6.31

Silica 5,200 mercaptopropyltrimethoxy 3,48 1, 96 Table 2: Experimental parameters and analytical data

Experiment Silica Monomer Reaction time TGA EA

h rel. Mass loss rel. increase

'o% C (%)

1 silica 1 styrene 5 10 12

2 silica 1 styrene 17 172 102

3 silica 2 styrene 5 23 25

4 silica 3 styrene 5 32 19

5 silica 4 styrene 5 31 9

6 silica 5 styrene 5 448 574

7 silica 2 MMA 5 1 9

8 silica 2 4-VP 5 59 55

TGA - Thermogravimetry: The thermogravimetric analyzes were carried out on a TGA-Q5000 from TA Instruments. When measuring in the range of T to 800 ° C air was used as purge gas. During the measurement, the sample temperature and mass were recorded continuously. The sample was heated at a heating rate of 10 K / min and then evaluated with TA Universal Analysis.

EA = elemental analysis: The combustion analyzes were carried out on a elemental elemental Vario EL elemental analyzer

Claims

Claims:

1. A process for the preparation of particulate finely divided solids having a modified surface characterized in that a vinylic monomer of the general

Formula {I)

(R ^ R ^ CR ¹ ^) where

1

R is the same or different and is hydrogen, or C optionally substituted with -C, -NCO, -NR ₂ , -COOH, -COOR ² , - halogen, -acryl, -epoxy, -SH, -OH or -CONR ² ₂ -bonded Ci-C2o ~ ^K ° Frlenwas erstoffrest, preferably a Ci-Cg hydrocarbon radical, more preferably one

C 1 -C 3 -hydrocarbon radical, or an aryl radical, or a heteroaryl radical such as pyridyl radical, or a C 1 -C -hydrocarbonoxy radical, preferably a C 1 -C -alkylcarboxy radical, particularly preferably a C 1 -C 6 -hydrocarbon radical, in each one or more, non-adjacent methylene units can be replaced by groups -O-, -CO-, -COO-, -OCO-, or -OCOO-, -S-, or -NR ² - and in which one or several mutually non-adjacent methine units may be replaced by groups, -N =, or "P-, or a heteroatom such as chloride,

Bromide -NR ² _a, or a C-linked carboxylic acid group, - COOH, or C-linked carboxylate group -COO ^"or C-bound Estergruppe -COOR ^2, -CHO or aldehyde group, keto group or -C (R ² 0} , or O-linked carboxylate group - OOCR ² , means and

R ^{2 is the} same or different and is hydrogen or an optionally substituted hydrocarbon radical or aryl radical,

where a, b, c, d = 0, 1 or 2, with the proviso that a + b = 2 and c + ^■ d = 2

is dispersed to a mixture with a particulate, finely divided solid having a high surface area, the particulate, finely divided, high surface area solid being treated by treatment with silanes of the general formula {II)

X _{x + x} . SiR ⁴ ₂ _ _x , - (CH ₂ ) _V -Y _f is silylated alone or in any mixtures, where X is halogen, nitrogen radical, OR ³ , OCOR ³ and

R ^{3 is} a C-0 bonded Ci-Cxs-hydrocarbon radical, preferably a Ci ~ Cg hydrocarbon radical, more preferably a Cx-C3-hydrocarbon radical, or an acetyl radical, and

R ^{4 is} a hydrogen atom or an optionally with -CN, -NCO, -NR ² ₂ , -COOH, -COOR ² , -halogen, -acrylic, -epoxy, -SH,

-OH or -CONR ² 2 substituted Si-C bonded 0χ-θ2O ~ hydrogen radical, preferably a C ^ _- CQ-

Hydrocarbon radical, particularly preferably a C 1 -C 3 -hydrocarbon radical, or an aryl radical, or C 1 -C -hydrocarboxy radical, preferably a C 1 -C -hydrocarboxy radical, particularly preferably a C 1 -C 4 -hydrocarboxy radical, in which in each case one or more, not adjacent methylene units by groups

-O-, ^» CO-, -COO-, -OCO-, or -OCOO-, -S-, or -NR ² - may be replaced and in which one or more, mutually non-adjacent methine units by groups, -N = or -P = can be replaced, is and

Y is hydrogen, unsaturated or single or multiple unsaturated C ₁ -C ₂ o-hydrocarbon radical, - OC (O) C (R) = CH ₂ (R = H, C ₁ -C ₈ -hydrocarbon radical, preferably a - C ₈ -hydrocarbon radical, especially preferably a C 1 -C ₃ -hydrocarbon radical), -vinyl, -hydroxyl, -halogen, phosphonato, -NCO, -NH-C (O) -OR (R =H) -hydrocarbon radical, preferably one C 1 -C 6 -hydrocarbon radical, particularly preferably a C 1 -C 3 -hydrocarbon radical

Hydrocarbon radical), glycidoxy, -SH, acid anhydrides such as succinic anhydride

and v = 0 to 10, preferably 0 to 5 and more preferably 0, 1, or 3, and '= 1 or 2

A method according to claim 1, characterized in that as compounds of formula I 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, methyl methacrylate, methacrylic acid

(MMA), acrylic acid, glycidyl acrylate, 2- (dimethylamino) ethyl methacrylate, ethylene glycol dimethacrylate, 3- (acryl oxyloxy) -2-hydroxypropyl methacrylate, styrene, 4-vinylpyridine

(4-VP) are used.

A method according to claim 1 or 2, characterized in that are used as a particulate finely divided solid, a solid having an average particle size less than 100 μπι, particularly preferably having a mean primary particle particle size of 5 to 100 nra.

Method according to one of claims 1 to 3, characterized in that is used as a particulate finely divided solid having a large specific surface, a metal oxide, preferably fumed silica, wherein the Metal oxide preferably has a specific surface area of from 0.1 to 1000 m ² / g (measured by the BET method according to DIN 66131 and 66132), particularly preferably a specific one

Surface of 10 to 500 m ² / g, most preferably from 30 to 450 m ² / g has.

Method according to one of claims 1 to 4, characterized in that the particulate solids having a large specific surface area in a proportion of 0.1 to 50 wt.% In the vinylic monomer of the general formula (I) preferably over a period of 10s to 2h be dispersed.

A method according to any one of claims 1 to 5, characterized in that the mixture is photosensitizer free.

Method according to one of claims 1 to 6, characterized in that electromagnetic radiation, electron beams or cathode rays are used as radiation, wherein the radiation has an exposure time of 10 seconds to 48 hours, preferably 60 seconds to 48 hours, more preferably 30 minutes to 24 hours ,

Method according to one of claims 1 to 7, characterized in that the reaction mixture during the photopolymerization a temperature of - 20 ° C to 100 ° C, preferably -20 ° C to 50 ° C, more preferably 0 ° C to 40 ° C.

Method according to one of claims 1 to 8, characterized in that after completion of the photopolymerization, the excess monomer is preferably by Abkondensie- ren in vacuum or filtration is removed.

Particulate finely divided solid having a large specific surface, characterized in that it is modified on its surface with a polymer layer consisting of monomers of the general formula III,

- (R ^ R ^ C-CR ¹ ^) -? (III), where

R ^{1 is} identical or different and Wassersto fatom, or optionally with -CN, -NCO, -NR ² ₂ , -COOH, -COOR ² , - halogen, acrylic, epoxy, -SH, -OH or -CONR ² ₂ substituted C-bonded C3_-C2o-carbon acid remainder, preferably a C ^ -Cg hydrocarbon radical, particularly preferably a C1-C3 hydrocarbon radical, or an aryl radical, or a heteroaryl radical such as pyridyl radical, or a C -C ₁₅ - hydrocarbonoxy, preferably a C] _Cg- hydrocarbonoxy radical, more preferably a C1-C4 hydrocarbonoxy radical, in which in each case one or more, not adjacent to each other methylene units by groups ~0-, -CO-, -COO -, -OCO ~, or -Oc00-, -S-, or -NR ² - may be replaced and in which one or more mutually non-adjacent methine units may be replaced by groups, -N =, or -P =, or a heteroatom such as chloride, bromide, -NR ² ₂ , or a C-bonded carboxylic acid group - COOH, or C ~ bonded carboxylate group -COO ^" , or C- g ebunden ester group -COOR ² , or aldehyde group -CHO, or keto group -C {0) R ² , or O-bonded carboxylate group - OOCR ² , means and

where a, b, c, d = 0, 1 or 2, with the proviso that a + b = 2 and c + d = 2.