EP1846495A1

EP1846495A1 - Hydroxyalkyl-functionalized fillers

Info

Publication number: EP1846495A1
Application number: EP06701799A
Authority: EP
Inventors: Oliver SCHÄFER; Christoph Briehn; Torsten Gottschalk-Gaudig
Original assignee: Wacker Chemie AG
Current assignee: Wacker Chemie AG
Priority date: 2005-02-03
Filing date: 2006-01-26
Publication date: 2007-10-24
Also published as: CN101115794A; KR100887273B1; US7576229B2; US20080139833A1; JP2008530258A; WO2006081979A1; KR20070100418A; DE102005005046A1

Abstract

The invention relates to particles P1 which carry on their surfaces the groups of formula (II), [O1/2SiR32-CR42-O-(CR42)b-OH], wherein R3 and R4 are the same or different and represent a hydrogen group or a monovalent C1-C20 hydrocarbon group which is optionally substituted with -CN, -NCO, -NRx2, -COOH, -COORx, -PO(ORx)2, -halogen, -acryl, -epoxy, -SH, -OH or -CONRx2 or a C1-C15 hydrocarbonoxy group in which one or more, non-neighboring methylene entities each can be replaced by groups -O-, -CO-, -COO-, -OCO-, or -OCOO-, -S-, or -NRx-, and in which one or mor, non-neighboring methine entities can be replaced by groups, -N=,-N=N-, or -P=, Rx represents a hydrogen group or a C1-C10 hydrocarbon group optionally substituted with -CN or halogen, and b is an integer of at least 1.

Description

Hydroxyalkyl-functionalized fillers

The invention relates to hydroxyalkyl-functionalized fillers, a process for their preparation and their use.

The filler is a finely divided solid, which changes its properties by addition to a matrix. Fillers are used today in the chemical industry for many purposes. You can change the mechanical properties of plastics such as: As hardness, tear resistance, chemical resistance, electrical or thermal conductivities, adhesion or shrinkage in temperature changes. Furthermore, they influence u. a. also the rheological behavior of plastic melts. By functionalizing fillers with chemically reactive groups, it is possible to improve the compatibility of the filler with the matrix and thus also optimize the property profile of the resulting compound. Preference is given to groups which can react with the matrix itself, such as carbinol groups, the z. B. can react with polyesters, polyurethanes or polyacrylates. In formulations, suitable modification of the fillers or particle surface ensures compatibility of the particle with the surrounding polymer matrix. In addition, if the particle surface has a suitable reactivity with respect to the matrix so that it can react with the binder system under the particular curing conditions of the formulation, it is possible to chemically incorporate the particles into the matrix during the curing, which often has a positive effect on the property profile of the compound affects.

EP-768347 describes a process for treating fillers which is derived from specific cyclic silanes of general go from the formula I, which can react with Metallhydroxidfunktionen to carbinol groups.

Here, R ^{1 is} a carbon radical having up to 20 carbon atoms, R ² is hydrogen or a hydrocarbon radical having up to 20 carbon atoms and a usually has a value of 3 or 4. It is emphasized that the reaction without the use of catalysts at temperatures between 25 ⁰ C and 15O ⁰ C is executed. In practice, however, there are some problems in carrying out the process: Although the β-membered ring with a = 4 can be obtained stably, it requires an increased reaction temperature and significantly longer reaction times in the reaction with metal hydroxide functions or silanol end groups , The synthesis of this stable 6-ring also requires a very complicated process in which an organometallic silicon compound is inserted into a tetrahydrofuran ring. The reactive in the sense of EP-768347 5-rings are unstable as a substance and tend to decompose or autopolymerization. Thus, the process for industrial use described in EP-768347 is not very suitable, since either the silane compounds used can not be obtained stably or are accessible only via technically complicated synthesis methods.

The object of the present invention was to provide a hydroxyalkyl-functional filler which can be prepared by a simple process. The invention relates to particles P1 which have residues of general formula II on their surface,

[O _1/2 SiR ³ ₂ -CR ⁴ ₂ -O- (CR ⁴ 2 'b -OH] (II),

in which

R 1 and R 3 are identical or different and are hydrogen or monovalent, optionally with -CN, -NCO, -NR ^X 2, -COOH, -COOR ^X , -PO (OR ^X ) 2, -halogen, -acrylic, -epoxy, -SH, -OH or -CONR ^X 2 substituted C] _- C20 ~ ^κ ° hydrogen radical or C] _- C] _5-Kohlenwasserstoffoxyrest, in each of which one or more, non-adjacent methylene units by groups -0-, -CO -, -C00-, -0C0-, or -OCOO-, -S-, or

-NR ^X - may be replaced, and in which one or more non-adjacent methine units may be replaced by groups, -N =, -N = N-, or -P =,

R ^{x is} hydrogen radical or an optionally substituted by -CN or halogen C _] _-C _] _o ~ hydrocarbon radical, b integer value of at least 1 means.

The particles P1 are preferably particles having a modified surface of a metal oxide, more preferably a silicic acid, particularly preferably a fumed silica, the surface being modified with groups of the general formula II.

The particles P1 according to the invention preferably have an average primary particle particle size, ie an average particle diameter, smaller than 100 nm, particularly preferably with an average primary particle particle size of 5 to 50 nm, these primary particles often do not exist in isolation in the silica, but are components of larger aggregates (definition according to DIN 53206), which have a diameter of 100 to 1000 nm and agglomerates (definition according to DIN 53206) build, depending on the external shear load sizes from 1 to 500 microns, wherein the silica has a specific surface of 10 to 400 m.2 / g (measured by the BET method according to DIN 66131 and 66132), wherein the silica has a fractal dimension of the mass D _m of smaller or equal to 2, 8, preferably equal to or less than 2, 7, more preferably from 2, 4 to 2, 6, and a density of surface silanol groups SiOH of less than 1.5 SiOH / nm 2, preferably of smaller as 0.5 SiOH / nm, more preferably smaller than 0.25 having .

The particles Pl can be produced by reaction of

(A) particles P of a material which has a surface with a radical selected from the group Me-OH, Si-OH, Me-O-Me, Me-O-Si, Si-O-Si, Me-OR ¹ and Si-OR ¹ , has (b) with compounds of general formula III

respectively . their hydrolysis, alcoholysis or polymerization products

R ^ and R ^ are the same or different and are hydrogen or monovalent, optionally with -CN, -NCO, -NR ^X 2, -COOH, -COOR ^X , -PO (OR ^X ) 2, -halo, -acryl, -epoxy , -SH, -OH or -C0NR ^x 2 substituted C] _- C2o ~ ^κ ° hlenwasserstoffrest, or C 1-C! _5-Hydrocarbonoxy in which one or more non-contiguous methylene units are represented by groups -O-, -CO-, -COO-, -OCO-, or -O-, -S-, or

-NR ^X - may be replaced and in which one or more mutually non-adjacent methine units may be replaced by groups, -N =, -N = N-, or -P =

R ^{x is} hydrogen radical or an optionally substituted by -CN or halogen Cχ-C _] _o ~ hydrocarbon radical, b integer value ≥ 1, n 0 or an integer value.

R ³ is preferably hydrogen, an alkyl, cycloalkyl or aryl radical, more preferably hydrogen, methyl, ethyl or phenyl radical, particularly preferably hydrogen, a methyl or ethyl radical.

R ⁴ is preferably hydrogen, an alkyl, cycloalkyl, aryl or arylalkyl radical, particularly preferably hydrogen, methyl, ethyl or phenyl radical, particularly preferably hydrogen.

The value n preferably assumes the values 0 or 1. Particularly preferred is n = 0.

The value b preferably assumes the values 1, 2 or 3. Particularly preferred is b = 2.

Optionally, the reaction mixture further comprises a protic solvent, preferably water or an alcohol. The use of compounds of general formula III allows the particle functionalization even in the absence of water. In a stoichiometric reaction, almost all metal OH and / or SiOH groups on the surface of the particle can be mixed with residues of the general. Saturate formula II. Remaining metal OH and / or SiOH groups that stabilize the are thus largely preventable.

Due to the high reactivity of the compounds of general formula III with methylene spacer between alkoxysilyl group and a heteroatom, these compounds are particularly suitable for the functionalization of SiOH or. MeOH-bearing particles P.

Particles P are characterized by having metal (MeOH), silicon hydroxide (SiOH), Me-O-Me, Me-O-Si, and / or Si-O-Si functions on their surface , via which a reaction with the compound of general formula III can take place.

In principle, all metal oxide and mixed metal oxide particles (for example aluminum oxides such as corundum, aluminum mixed oxides with other metals and / or silicon, titanium oxides, zirconium oxides, iron oxides, zinc oxides, etc.), silica particles (for example colloidal oxides) can be used as the particles P. Silicic acid, fumed silica, precipitated silica, silica sols, mineral glasses, quartz glasses or window glass) or silicon oxide compounds in which some valences of silicon are provided with organic radicals (for example silicone resins). Furthermore, it is also possible to use metals with an oxidized surface, such as silicon, aluminum, iron.

The particles P preferably have an average particle size of less than 1 mm, the average size of the particles being determined by transmission electron microscopy.

With particular preference, they have an average particle size of 5 to 100 nm. These primary particles can be present in isolation. However, they can also be components of larger aggregates and agglomerates.

Preferred particles P 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), more preferably from 10 to 500 nm ^ / g.

The particle P may have aggregates (definition according to DIN 53206) in the range of preferably diameters 100 to 1000 nm, wherein the metal oxide of aggregates constructed agglomerates (definition according to DIN 53206), which depends on the external shear stress (eg by the measurement conditions) sizes of 1 to 1000 microns may have.

For technical reasons, the particle P is preferably an oxide with a covalent bond fraction in the metal-oxygen bond, preferably an oxide in the solid state of the main and subgroup elements, such as the third main group, 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 a 4th transition group oxide, such as titanium dioxide, zirconium oxide, or hafnium oxide. Other examples are stable nickel, cobalt, iron, manganese, chromium or vanadium oxides.

Particular preference is given to aluminum (III), titanium (IV) and silicon (IV) oxides, such as, for example, precipitated silicas or silica gels, or aluminum oxides, titanium dioxides or silicas prepared in processes at elevated temperature, for example pyrogen produced aluminas, titanium dioxides or silicas. Other solids which can be used as particles P are silicates, δ

Aluminates or titanates, or aluminum phyllosilicates, such as bentonites, such as montmorillonites, or smectites or hectorites. Further solids which can be used as particles P are carbon blacks, such as flame blacks, furnace blacks, so-called furnace blacks, or carbon blacks which can be used as dye or as reinforcing filler or as rheological additive, so-called "carbon black" carbon blacks.

Particularly preferred is fumed silica, which is prepared in a flame reaction of organosilicon compounds. The production takes place z. B. of silicon tetrachloride, methyldichlorosilane, hydrogentrichlorosilane, hydrogenmethyldichlorosilane, other methylchlorosilanes or alkylchlorosilanes, also mixed with hydrocarbons, eg. B. in a hydrogen-oxygen flame, or even a carbon monoxide

Oxygen flame. The preparation of the silica can be carried out optionally with and without the 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 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 D _s is as follows defined: Particle surface A is proportional to the particle radius R high D ₃ .

Preferably, the precipitated silica has a fractal dimension of the mass D _m of preferably less than or equal to 2, 8, preferably equal to or less than 2, 7, more preferably from 2, 4 to 2, 6. The fractal dimension of the mass D _m is defined as follows: Particle mass M is proportional to the particle radius R high D _m . The silica preferably has a density in a chemical reaction accessible surface silanol groups SiOH of less than 2, 5 SiOH / nm ^2, preferably less than 2, 1 SiOH / nm ^2, preferably less than 2 SiOH / nm ^2, more preferably from 1.7 to 1.9 SiOH / nm ² .

It is possible to use silicas prepared by a wet-chemical route or silicas prepared at high temperatures (greater than 1000 ^° C.). Particular preference is given to pyrogenically prepared silicic acids. It is also possible to use hydrophilic metal oxides which, freshly prepared, come directly from the burner, are temporarily stored or are already packaged in a commercial manner. It is also possible to use hydrophobized metal oxides or silicic acids, eg. B. commercially available silicas used. It is possible to use uncompressed silicas having bulk densities of preferably less than 60 g / l, but also compacted silicas having bulk densities of preferably greater than 60 g / l.

It can be used any mixtures of said solids for surface modification, such. B. Mixtures of metal oxides or silicas of different BET surface area, or mixtures of metal oxides with different degree of hydrophobing or Silyliergrad.

For surface modification, the compounds of general formula III can be used alone or in any desired mixtures with organosiloxanes composed of units of the formulas

(R53SiO] _ / 2), and / or (R ⁵ 2Si02 / 2 W and / or

(R ⁵ Si0 _3/2) are used, the number of these units in egg nem organosiloxane is at least 2, and R ^{5 is} an optionally mono- or polyunsaturated, monovalent, optionally halogenated, hydrocarbon radical having preferably 1 to 18 carbon atoms or halogen, nitrogen radical, OR ⁶ , OCOR ⁶ , O (CH 2) _X OR ⁶ where R ^{6 is} hydrogen or a monovalent one

Hydrocarbon radical having 1 to 18 carbon atoms, and the radicals R ^{5 may} be the same or different. The organosiloxanes are preferably liquid at the coating temperature.

Examples of R 1 are alkyl radicals such as the methyl radical, the ethyl radical, propyl radicals such as the isopropyl or n-propyl radical, butyl radicals such as the t- or n-butyl radical, pentyl radicals such as the neo, iso or n Pentyl radicals, hexyl radicals such as the n-hexyl radical, heptyl radicals such as the n-heptyl radical, octyl radicals such as the 2-ethylhexyl or the n-octyl radical, decyl radicals such as the n-decyl radical, dodecyl radicals such as the n-dodecyl radical, hexadecyl radicals such as n Hexadecyl radical, octadecyl radicals such as the n-octadecyl radical, alkenyl radicals such as the vinyl radical, the 2-allyl radical or the 5-hexenyl radical, aryl radicals such as the phenyl, the biphenyl or naphthenyl radical, alkylaryl radicals such as benzyl, ethylphenyl, toluyl - or the xy- lylreste, halogenated alkyl radicals such as the 3-chloropropyl, the 3, 3, 3-trifluoropropyl or the Perfluorhexylethylrest, halogenated aryl radicals such as chlorophenyl or chlorobenzyl.

Preferred examples of R 1 are the methyl radical, the octyl radical and the vinyl radical, particularly preferably the methyl radical.

Examples of organosiloxyariene are linear or cyclic dialkylsiloxanes having an average number of dialkylsiloxy units of greater than 2, preferably greater than 10.

The dialkylsiloxanes are preferably dimethylsiloxanes. Examples of linear polydimethylsiloxanes are those having the terminal groups: trimethylsiloxy, dimethylhydroxysiloxy, dimethylchlorosiloxy, methyldichlorosiloxy, dimethylmethoxysiloxy, methyldimethoxysiloxy, dimethylethoxysiloxy, methyldiethoxysiloxy, dimethylacetoxysiloxy, methyldiacetoxysiloxy; especially Preferred are trimethylsiloxy and dimethylhydroxysiloxy. The end groups can be the same or different.

The particle according to the invention can be prepared in continuous or batch processes. The silylation process may be composed of one or more steps.

Preferably, the silylated particle is prepared by a process comprising the following steps:

(A) production of a particle,

(B) silylation of the particle comprising the steps

1) optionally covering the particle of a compound of general formula III, (2) reaction of the particle with the compound of general formula III

(3) Purification of Particle of Excess Compound of General Formula III.

The silylation is preferably carried out in an atmosphere which does not result in the oxidation of the silylated metal oxide, i. H. preferably less than 10% by volume of oxygen, more preferably less than 2.5% by volume, best results being achieved at less than 1% by volume of oxygen, d. H. that the reaction is carried out in a predominantly inert carrier gas.

Assignment, reaction and purification can be carried out as a batch or continuous process, for technical reasons, preference is given to a continuous reaction. The assignment is preferably carried out at temperatures of -30 - 25O ⁰ C, preferably 20-150 ⁰ C, more preferably 20-120 ⁰ C; Preferably, the occupation step is cooled to 30-50 ⁰ C.

The residence time is 1 min. - 48 h, preferably 15 min to 360 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 outside / atmospheric pressure, is preferred.

The compound of general formula III is preferably added to the particles as a liquid and in particular mixed into 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 parts with atomizers or gas-solid exchange units with movable, rotating or static internals, which allow a homogeneous mixing of the silane with the powdered metal oxide.

The silane of the general formula III is preferably added to the metal oxide as a finely divided aerosol which has a sinking rate of 0.1 to 20 cm / s and a droplet size with an aerodynamic particle radius of 5 to 25 μm. Preferably, the loading of the metal oxide and the reaction with the compound of the general formula III takes place under mechanical or gas-borne fluidization. Particularly preferred is the mechanical fluidization.

Gas-borne fluidization may be by any inert gas that does not react with the compound of general formula III, the metal oxide, and the silylated metal oxide. that is, do not lead to side reactions, degradation reactions, oxidation processes and flame and explosion phenomena. Preferably, the inert gas is N 2, Ar, others

Noble gases or CO2. The supply of the gases for fluidization preferably takes place in the range of empty-tube gas velocities of 0.55 to 5 cm / s, more preferably of 0.5-2.5 cm / s. Particular preference is given to the mechanical fluidization which takes place without additional gas addition beyond the inertization, by paddle stirrers, anchor stirrers and other suitable stirring organs.

In a particularly preferred embodiment, unreacted compound of general formula III and exhaust gases from the purification step are returned to the step of occupying the metal oxide; this can be done partially or completely, preferably at 10-90% of the total volume flow of the 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 mass 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 may be recommended.

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

The return of the Abreinigungprodukte the Silylierreaktion in the occupancy is preferably carried out continuously. The reaction is preferably carried out at temperatures of -30 - 250 ⁰ C, preferably 20-150 ⁰ C and particularly preferably at 20-120 ⁰ C. The reaction time is 1 min to 48 h, preferably 15 min. until 6 h.

Optionally, protic solvents may be added, such as liquid or volatilizable alcohols or water; typical alcohols are isopropanol, 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 metal oxide, is added, more preferably 5 to 25% by weight. Particularly preferred is water. Optionally, acidic catalysts of acidic character, in the sense of a Lewis acid or a Brönsted acid, such as chlorine-hydrogen or basic catalysts of basic character, can be added in the sense of a Lewis base or a Brönsted base, such as ammonia. When catalysts are added, they are preferably added in traces, i. H . in amounts less than 1000 ppm. Most preferably, no catalysts are added.

The dedusting is vozugsweise at a cleaning temperature of 20 to 200 ⁰ C, particularly preferably from 50 ⁰ C to 150 ⁰ C, particularly preferably from 50 to 100 ⁰ C. The cleaning step is preferably characterized by movement, with slow movement and low mixing being particularly preferred. The stirring elements are advantageously adjusted and moved so that preferably a mixing and fluidization occurs. The cleaning step may further be characterized by increased gas input, corresponding to an empty-tube gas velocity of preferably 0.001 to 10 cm / s, preferably 0, 01 to 1 cm / s. This can be done by any inert gases that are not with the silane of general formula III, the metal oxide or particles, and the silylated metal oxide or the silylated particles react, so do not lead to side reactions, degradation reactions, oxidation processes and flame and explosive phenomena, such as preferably N2, Ar, other noble gases or also

CO ₂ .

In a further preferred embodiment of the invention, colloidal silicon or metal oxides are used as particles P, which are preferably present as a dispersion of the corresponding oxide particles of micron or submicron size in an aqueous or organic solvent. In this case, the oxides of the metals aluminum, titanium, zirconium, tantalum, tungsten, hafnium, tin or zinc can preferably be used. Preference is given to using organic particle solutions or suspensions which are preferably reacted with compounds of the general formula III.

One or more different particle types P can be used. For example, filler systems can be produced which contain corundum in addition to SiO 2.

Examples of compounds of general formula III which are preferably used are 2, 2-dimethyl-1,4-dioxa-2-silacyclohexane; 2, 2, 5-trimethyl-1,4-dioxa-2-silacyclohexane, 2,2, β-trimethyl-1,4-dioxa-2-silacyclohexane; 2, 2, 5, 6-tetramethyl-1,4-dioxa-2-silacyclohexane; 2, 2-dimethyl-1,4-dioxa-2-silacycloheptane; 2, 2, 5-trimethyl-1,4-dioxa-2-silacycloheptane; 2, 2, β-trimethyl-1,4-dioxa-2-silacycloheptane; 2, 2, 7-trimethyl-1,4-dioxa-2-silacycloheptane; 2, 2, 5, 7-tetramethyl-1,4-dioxa-2-silacycloheptane. For the functionalization of the particles, a compound of general formula III can be used individually or a mixture of different compounds of general formula III or else a mixture of compounds of general formula III with other silanes.

If compounds of the general formula III are used, these react easily and in a targeted manner with good yields to give carbons. Compounds of general formula III are stable, Ia gerfähig, can be easily from simple precursors, z. B. according to DE 1593867 A, synthesize and therefore are particularly suitable for use on an industrial scale.

Preferably, compounds of general formula III, compounds of general formula IV

used in which

R3, R4 and b have the meanings already mentioned.

Particularly preferred b is 2, R ^ hydrogen radical and R ^ is methyl or ethyl radical.

Such a method may uncatalyzed, preferably at temperatures of 0 ⁰ C to 200 ⁰ C, are performed. Reaction temperatures are preferably used edoch j of at least 40 ⁰ C. However, the process can still be improved by adding certain catalysts. These catalysts are acidic or basic compounds and cause both reaction times and reaction temperatures can be reduced.

The catalyst used is an inorganic or organic Lewis acid or Lewis base, such as organic Bronsted acid or base, an organometallic compound or a halide salt.

Preferred acids used are carboxylic acids, partially esterified carboxylic acids, in particular monocarboxylic acids, preferably formic acid or acetic acid, or unesterified or partially esterified mono-, oligo- or polyphosphoric acids. Preferred bases are preferably alkylammonium hydroxides, alkylammonium siloxanes, ammonium alkoxides, alkylammonium fluorides, amine bases or metal alcoholates or metal alkyls. Preferred metal alcoholates are lithium or sodium alcoholates. Preferred organometallic reagents are organo-tin compounds, organo-zinc compounds or organotitanium compounds or organo-lithium compounds or. Gringard reagents. Preferred salts are tetraalkylammonium fluorides.

Preferred are inter alia phosphoric acids of the general formula V

O = P (OR 5) ₃ _ _V (OH) _V, (V),

in the

R5, an optionally substituted linear or branched C] _- C3o-alkyl, C2-C4 alkenyl or _Q alkoxyalkyl, C2-C4Q-polyether, C5-C] _4-cycloalkyl or

-Arylrest and v represent the values 0, 1 or 2. The catalysts used are deactivated after the functionalization reaction of the silanol groups, preferably by adding so-called anti-catalysts or catalyst poisons, before they can lead to cleavage of the Si-O-Si groups. This side reaction is dependent on the catalyst used and does not necessarily occur, so that it may optionally be possible to dispense with a deactivation. Examples of catalyst poisons are in the use of bases, for. B. Acids and when using acid, e.g. B. Bases, which ultimately leads to a simple neutralization reaction with corresponding neutralization products, which can optionally be filtered off or extracted. Depending on the use of the product, the corresponding reaction product between catalyst and catalyst poison can either be removed from the product or remain in the product.

Preferably, the reaction product after neutralization has a slightly acidic pH of 3 to 7.

In the process for the preparation of carbinol-modified fillers, the amount of the compound used of the general formula III is dependent on the amount of Me-OH groups to be functionalized in the filler. However, if a complete functionalization of the OH groups is to be achieved, the compound having units of the general formula III must be added in at least equimolar amounts, based on n. If one uses compound with units of the general formula III in excess, unreacted compound can subsequently either be distilled off or hydrolyzed and then, if appropriate, distilled off.

The method at 0 ⁰ C to 200 ⁰ C, particularly preferably at 40 ⁰ C to 15O ⁰ C. The process can be carried out both with the inclusion of solvents, or even without the use of solvents in suitable reactors. If appropriate, work is carried out under reduced pressure or under elevated pressure or at atmospheric pressure (0.1 Mpa).

When using solvents are inert, especially aprotic solvents such as aliphatic hydrocarbons, such as. B. Heptane or decane, and aromatic hydrocarbons such. B. Toluene or xylene, preferred. Also, ethers such as THF, diethyl ether or MTBE can be used. The amount of solvent should be sufficient to ensure sufficient homogenization of the reaction mixture. Solvent or solvent mixtures with a boiling point or. Boiling range of up to 12O ⁰ C at 0, 1 MPa are preferred.

In addition, during the silylation or after the purification, additional methods are employed for mechanical densification of the metal oxide, such as press rolls, grinding units such as edge mills and ball mills, continuous or discontinuous, compression by screws or screw mixers, screw compressors, briquetting or compaction by suction of the air or gas content by suitable vacuum methods.

Particularly preferred is a mechanical densification during the silylation, in step (B) 2) the reaction by press rolls, the above-mentioned grinding units such as ball mills or compaction by screws, screw mixers, screw compressors, briquetting.

In a further particularly preferred procedure, processes for the mechanical compaction of the metal oxide are used following the purification, such as compaction by aspiration of the air or gas contents by suitable vacuum methods or press rolls or a combination of both processes. In addition, in a particularly preferred procedure subsequent to the purification, processes for deagglomerating the metal oxide can be used, such as pin mills or devices for grinding sifting, such as pin mills, hammer mills, countercurrent mills, impact mills or devices for grinding sifting.

The compound of general formula III is preferably in an amount greater than 0, 5 wt. % (based on the metal oxide), preferably greater than 3 wt. % (based on the metal oxide), more preferably preferably greater than 5 wt.% (Based on the metal oxide) used.

In a preferred embodiment of the invention, the surface-modified metal oxide is further characterized by being used in polar systems, such as solvent-free polymers and resins, or solutions, suspensions, emulsions and dispersions of organic resins, in aqueous systems or in organic solvents (e.g. .: Polyester, vinyl esters, epoxides, polyurethanes, alkyd resins and others) has a high thickening effect. It is thus suitable as a rheological additive in the systems mentioned.

In a preferred embodiment of the invention, the surface-modified metal oxide is further characterized in that it has a low thickening effect in non-polar systems, such as uncrosslinked silicone rubber, but at the same time shows a high reinforcing effect in the crosslinked silicone rubbers and is therefore outstandingly suitable as reinforcing filler for silicone rubbers ,

The invention thus also relates to a reinforcing filler or a theological additive, which is characterized in that it comprises particles P1 according to the invention, preferably a metal oxide according to the invention, particularly preferably a silica according to the invention.

In a preferred embodiment of the invention, the surface-modified particles Pl are characterized in that in powdery systems caked or agglomerated, for. B. prevented under the influence of moisture, but also does not tend to Reagglomeration, and thus the undesirable separation, but powder is flowable and thus allows load-stable and storage-stable mixtures.

In general, particle amounts of 0.1 to 3% by weight, based on the powdery system, are used.

This is especially true for use in non-magnetic and magnetic toners and developers and charge control tools, e.g. B. in contactless or electrophotographic printing / reproduction processes, the 1- and 2-component systems can be. This also applies in powdered resins used as paint systems.

The invention further relates to the use of the particles P1 of the invention in systems of low to high polarity as a viscosity-giving component. This applies to all solvent-free, solvent-borne, water-dilutable, film-forming paints, adhesives, sealants and potting compounds as well as other comparable systems. The particle can be used in systems such as: epoxy systems,

Polyurethane systems (PUR), vinyl ester resins, unsaturated polyester resins, - water-soluble and water-dispersible resin systems, low-solvent resin systems, so-called "high solids", and solvent-free resins, which are applied in powder form.

As a rheological additive in these systems, the particles P1 provide the required viscosity, intrinsic viscosity, thixotropy and a flow limit which is sufficient for standing on vertical surfaces.

The particles P1 can be used specifically as a rheological additive and reinforcing filler in uncrosslinked and crosslinked silicone systems such as silicone elastomers composed of silicone polymers such as polydimethylsiloxanes, fillers and other additives. These can be z. B. with peroxides or via addition reactions, the so-called hydrosilylation, between olefinic groups and Si-H groups are crosslinked or via condensation reactions between silanol groups, eg. B. those that develop under the influence of water.

The particles P1 can also be used as reinforcing filler, rheological additive and additionally as crosslinking component in elastomers, resins, reactive resins, and polymers.

The particles Pl can also be used as a rheological additive and reinforcing filler and as an additional crosslinking component for improving the mechanical properties, such as impact resistance or scratch resistance of reactive resin systems, such. B. Epoxy, polyurethane, vinyl ester, unsaturated polyester or methacrylate resins. This applies to all solvent-free, solvent-based, water-dilutable, film-forming paints, adhesives, sealants and potting compounds and other comparable systems. Typical amounts used of the modified particle are in the range of 3 - 50% based on the resin system.

Another object of the invention are toners, developers and charge control adjuvants containing a surface-modified metal oxide according to the invention. Such developers and toners are for. B. magnetic 1-component and 2-component toner, but also non-magnetic toner. These toners may consist of resins, such as styrene resins and acrylic resins, and preferably be ground to particle distributions of 1-100 .mu.m, or may be resins used in polymerization processes in dispersion or emulsion or solution or in bulk to particle distributions of preferably 1-100 μm were produced. The metal oxide is preferably used to improve and control the powder flow behavior and / or to regulate and control the triboelectric charging properties of the toner or developer. Such toners and developers can be used in electrophotographic printing and printing processes, and are useful in direct image transfer processes.

A toner typically has the following composition: solid resin as a binder, which is sufficiently hard to produce a powder thereof, preferably having a molecular weight above 10,000, preferably having a proportion of polymers of a molecular weight below 10,000 of less than 10% by weight. , z. B. a polyester resin which may be a co-condensate of diol and carboxylic acid, ester or anhydride, e.g. B. with an acid number of 1 to 1000, preferably 5 to 200, or a polyacrylate or a polystyrene, or mixtures, or co-polymers thereof, and having a mean particle diameter smaller than 20 microns, preferably less than 15 microns, more preferably less than 10 microns.

The toner resin may contain alcohols, carboxylic acids and polycarboxylic acid. Technically conventional dyes, such as black carbon black, carbon black, cyan dyes, magenta dyes, yellow dyes.

- Typically positive charge control agents: charge control additives, eg. B. of the nigrosine dye type, or triphenylmethane dyes substituted with tertiary amines, or quaternary ammonium salts such as CTAB (cetyltrimethylammonium bromide = hexadecyltrimethylammonium bromide), or polyamines, typically less than 5% by weight. %.

Optionally negative charge control agents: Charge controlling additives such as metal-containing azo dyes, or copper phthalocyanine dyes, or metal complexes of, for example, alkylated salicylic acid derivatives or benzoic acid, especially with boron or aluminum, in the required amounts, typically less than 5 wt %.

Optionally, magnetic powders may be added to produce magnetic toners, such as. B. Powders that can be magnetized in a magnetic field, such as ferromagnetic substances, such as iron, cobalt, nickel, alloys, or compounds such as magnetite, hermatite or ferrite.

Optionally, developers may also be added, such as iron powder, glass powder, nickel powder, ferrite powder.

- Metal oxide is in contents, based on a solid resin binder with 20 micron average particle diameter, greater than 0, 01 wt.%, Preferably greater than 0, 1 wt.% Used. With decreasing average particle diameter of the binder, higher levels of metal oxide are generally required, with the necessary amount of metal oxide increasing in inverse proportion to the particle diameter of the binder. The content of me- However, tallow oxide is preferably less than 5% by weight in each case. % based on binder resin.

- Other inorganic additives, such as finely divided and coarse silica, including those with 100 to 1000 nm average diameter, aluminum oxides, such as pyrogenic aluminas, titanium dioxides, such as pyrogenic or Anastas or rutile, zirconium oxides, are possible.

Waxes, such as paraffinic waxes having 10 to 500 carbon atoms, silicone waxes, olefinic waxes, waxes having an iodine value of less than 50, preferably less than 25, and a saponification number of 10 to 1000, preferably 25 to 300, can be used.

The toner can be used in various development processes, such as electrophotographic imaging and reproduction, such as. B. magnetic brush method, cascade method, use of conductive and non-conductive magnetic systems, powder cloud method, development in impression and others.

In the following examples, unless otherwise indicated, all amounts and percentages are by weight and all pressures are 0.10 MPa (abs.).

Example 1: Preparation of 2, 2-dimethy1- [1,4] dioxa-2-silacyclohexane

A mixture of 103 9 g (0 75 mol) Chlormethyldimethylmethoxy- silane, 46 6 g (0 75 mol) of ethylene glycol and 200 ml of 1, 4 diisopropyl pylbenzol were heated to 150 ⁰ C and stirred for 3 hours. In this case, 24 g (0, 75 mol) of methanol were distilled off. Then, at 15O ⁰ C slowly added dropwise 138, 8 g (0, 75 mol) of tributylamine. After dropwise addition, the mixture was stirred at 150 ^° C. for a further 3 hours. The resulting salt tributylammonium chloride was filtered off. The filtrate was fractionally distilled twice under normal pressure, wherein at the 132 ⁰ C passing fraction 26 g of pure 2, 2-dimethyl-2-sila-l, 4-cyclohexane (132, 23 g / mol, 20 mmol) in a yield of 27%.

Example 2:

At a temperature of 25 ⁰ C under an inert gas N2 are added to 100 g of fumed hydrophilic silica having a moisture content less than 1%, a HCl content of less than 100 ppm and with a specific surface area of 200 m ^ / g (measured by the BET Method according to DIN 66131 and 66132) (available under the name WACKER HDK S13 from Wacker Chemie AG, Munich, D), a solution of 8.5 g of 2, 2-dimethyl- (1,4) -dioxa-2-silane Cyclohexane and 0, 25 g of triethylamine in 10 ml of MeOH in finely divided form over a single-fluid nozzle (pressure 5 bar) zugedüst. The thus loaded silica is then under N2 0, 5 h at a temperature of 25

⁰ C fluidized and then reacted for 4 h at 140 ⁰ C in a 100 1 drying oven under N2 to the reaction. A white silicic acid powder with a homogeneous silylating agent layer is obtained. The analytical data are listed in Table 1.

TABLE 1 Analytical data of the silica from Example 2

The analysis was carried out by the following methods:

Carbon content (% C)

Elemental analysis on carbon; Burning the sample at > 1000 ⁰ C in the 0 ₂ stream, detection and quantification of the resulting CO ₂ with IR; Device LECO 244

BET measured according to the BET method according to DIN 66131 and 66132

pH

4% (wt.%) Suspension of the silica in saturated aqueous common salt solution: methanol = 50: 50

Example 3:

At a temperature of 3O ⁰ C, in a 1 1-3-necked flask under inert gas N2 to 10 g of hydrophilic silica, m with a moisture content <1% and an HCl content of <100 ppm and with a specific surface area of 130 ^ / g (measured according to the BET method according to DIN 66131 and 66132) (available under the name WACKER HDK S13 from Wacker Chemie AG, Munich, D), 6.5 g of 2, 2-dimethyl- [1,4] dioxa-2 -sila-cyclohexane and 60 mg of lithium methoxide solution (10% in methanol) (300 ppm). The mixture was homogenized by stirring and then heated to 6O ⁰ C for 3 h. After neutralization of the catalyst with phosphoric acid, the toluene and excess silane were removed. The silicic acid thus charged no longer showed any free Si-OH groups in 29 Si NMR.

Example 4:

.% SiO _2, mean particle size - at a temperature of 25 ⁰ C in a 100 ml 3-neck of the company NIS san Chemicals, 30 weight be pistons 50, 0 g of an SiO ₂ organosol (IPA-ST® 12 nm) 1.98 g (14, 9 mmol) of 2, 2-dimethyl- [1, 4] dioxa-2-sila-cyclohexane. The mixture is stirred for 6 h at 5O ⁰ C and for an additional 24 h at room temperature to yield a clear suspension containing egg weak Tyndall effect. ¹ H-NMR and ²⁹ Si-NMR show that approx. 80% of the cyclic silane have reacted with the particle. This turnover can not be further increased by longer reaction times.

Example 5:

At a temperature of 25 ⁰ C in a 100 ml 3-necked flask are 50, 0 of an SiO 2 organosol g (IPA ST® from Nissan Chemicals, 30 wt -.% SiO _2, mean particle size 12 nm) 1, 98 g (14, 9 mmol) of 2, 2-dimethyl [1, 4] dioxa-2-sila-cyclohexane given. The mixture is stirred for 48 h at 2O ⁰ C to give a clear suspension, which shows a weak Tyndall effect. ¹ H-NMR and ²⁹ Si-NMR show that approx. 80% of the cyclic silane have reacted with the particle.

Claims

Claims:

Particles P1 having on their surface residues of the general formula (II), [O _1/2 SiR ³ ₂ -CR ⁴ ₂ -O- (CR ⁴ ₂ ) _b -OH] (II), wherein

R ³ and R ^{4 are the} same or different and are hydrogen or monovalent, optionally with -CN, -NCO, -NR ^X 2, -COOH, -COOR ^X , -PO (OR ^X ) ₂ , -halo, -acrylic, -epoxy , -SH, -OH or -CONR ^X ₂ substituted, Ci-C2o-hydrocarbon radical or Cχ-Ci ₅ -Kohlenwasserstoffoxyrest, in which j in each case one or more, non-adjacent methylene units by groups -0-, -CO-, -COO -, -0C0-, or -Oc00-, -S-, or -NR ^X - may be replaced, and in which one or more mutually non-adjacent methine units by groups, -N =, -N = N-, or - P = can be replaced,

R ^{x is} hydrogen radical or a C 1 -C 10 -hydrocarbon radical optionally substituted by -CN or halogen, b is an integer value of at least 1.

2. Particles according to claim 1, characterized in that they are particles having a modified surface of a metal oxide, particularly preferably a silica, particularly preferably a fumed silica, wherein the surface is modified with groups of the general formula II.

3. Particles according to claim 1 or 2, characterized in that they have an average primary particle size of less than 100 nm, more preferably having an average primary particle size of from 5 to 50 nm.

4. Particles according to claim 1, 2 or 3, characterized in that they have a specific surface of 10 to 400 m.2 / g.

5. Particles according to one of claims 1, to 4, characterized in that it has a fractal dimension of the mass D _m less than or equal to 2, 8, and a density of surface silanol groups SiOH of less than 1, 5 SiOH / nm ^ , exhibit .

6. A process for the preparation of particles according to claim 1 to 5, by reaction of

(A) Particles P of a material which has a surface with a residue selected from the group Me-OH, Si-OH, Me-O-Me, Me-O-Si, Si-O-Si, Me-OR ¹ and Si-OR ¹ has (b) with compounds of general formula III

or their hydrolysis, alcoholysis or polymerization, wherein

R ³ , R ^{4 is} a hydrogen atom or monovalent, optionally with -CN, -NCO, -NR ^X ₂ , -COOH, -COOR ^X , -PO (OR ^X ) ₂ , -halogen, -acrylic, -epoxy, -SH, -OH or -CONR ^X ₂ substituted, Ci-C ₂ O- hydrocarbon radicals or Ci-Cis-Kohlenwasserstoffoxyreste, in which j in each case one or more, non-adjacent methylene units by groups -0-, -CO-, -C00-, - may be replaced and be substituted in which one or more nonadjacent methine units by groups -N =, -N = N-, or -P = - 0C0- or -OCOO-, -S-, or -NR ^X R ^{x can be} hydrogen or a C 1 -C 10 -hydrocarbon radical optionally substituted by -CN or halogen, b means integer values of at least 1, n 0 or an integer value.

7. The method according to claim β, characterized in that as compounds of the general formula III compounds of the general formula IV

be used, in which

R ^, R ^ and b have the meanings already mentioned.

8. The method according to claim 6 or 7, characterized in that the particles P is a fumed silica having a fakt- talen dimension of the surface less than or equal to 2, 3 more preferably less than or equal to 2, 1, more preferably from 1, 95 bis 2, 05, are.

9. A process for the preparation of particles according to claim 1 to 5, characterized in that it comprises the following steps:

(A) production of a particle,

(B) Silylation of the particle comprising the steps

(1) Loading of the particle with a compound of general formula III, (2) Reaction of the particle with the compound of general formula III

(3) Purification of Particle of Excess Compound of General Formula III.

10. Method according to one of claims 6 to 9 characterized indicates that the compounds of general formula III in a mixture with organosiloxanes composed of units of the formulas (R ⁵ ₃ Si0i _{/ 2} ), and / or (R ⁵ ₂ Si0 _2/2 ) _t and / or

(R ⁵ Si0 _3/2 ) are used, wherein the number of these units in an organosiloxane is at least 2, and R ^{5 is the} same or different and monovalent, optionally mono- or polyunsaturated, optionally halogenated, hydrocarbon radical having preferably 1 to 18 C. Atom, or halogen radical, nitrogen radical, OR ⁶ , OCOR ⁶ , 0 (CH ₂ ) _x 0R ⁶ , where R ^{6 is} hydrogen or a monovalent hydrocarbon radical having 1 to 18 carbon atoms.

11. The method according to any one of claims 6 to 10, characterized in that it is carried out in an atmosphere which does not lead to the oxidation of the silylated metal oxide.

12. reinforcing filler or rheological additive, which is characterized in that it comprises particles according to claim 1 to 5.

Toner, developer or charge control agent, characterized in that it comprises particles according to claims 1 to 5.