WO2007057314A1

WO2007057314A1 - Method for modifying the surface of solid materials by means of an infrared lamp

Info

Publication number: WO2007057314A1
Application number: PCT/EP2006/068106
Authority: WO
Inventors: Paul Fuchs; Werner Emberger
Original assignee: Wacker Chemie Ag
Priority date: 2005-11-15
Filing date: 2006-11-06
Publication date: 2007-05-24
Also published as: DE102005054409A1

Abstract

Disclosed is a method for heating particulate solid materials during surface modification. Said method is characterized in that the particulate solid material is heated using an infrared lamp. The inventive method is used for modifying SiO<SUB>2</SUB> with organosilicon compounds.

Description

METHOD FOR THE SURFACE MODIFICATION OF SOLIDS BY AN INFRARED LAMP

The invention relates to a process for heating particulate solids during surface modification.

Currently, the heating of reactors for

Surface modification of particulate solids realized by outside of the reactor adjacent heating elements (heating coil, heating shells, heating jackets).

Disadvantage of this method is the low temperature of the heating elements of <1000 ⁰ C. At this low temperature is in the reactor wall, which usually consist of steel or steel alloys, a large part of

Radiation energy converted into heat. As a result, the reactor wall is significantly warmer than the internal particles to be heated, which in turn are heated by heat conduction from the reactor surface. On the hot reactor wall surfaces decomposition reactions of the surface modification reagents can occur, which can lead to quality losses of the target product. In addition, the temperature control by the heated reactor wall is very sluggish, which complicates the short-term adjustment of the reaction temperature.

The object of the invention is to improve the prior art and in particular particulate solids during the surface modification in a reactor tube, consisting of quartz or Duran, with a built-in stirrer to an internal temperature of about 50 to 350 ⁰ C to bring wherein the wall temperature of the reactor should not be warmer than the particles to be heated so as not to overheat the product. The invention relates to a method for heating particulate solids during the surface modification, characterized in that the particulate solid is heated by means of an infrared lamp.

The particulate solids are particulate inorganic solids, preferably precipitated or pyrogenic metal oxides such as silicas, titanium dioxides, aluminas, zirconium dioxides, iron oxides and others, and their mixed oxides, particularly preferred is fumed silica.

The particulate solids are heated during surface modification.

The surface modification is a treatment of particulate solids with surface modification reagents, such as alcohols, carboxylic acids and their derivatives, titanates and organosilicon compounds, being preferred

Organosilicon compounds. The organosilicon compounds are preferably organosilane of the formula I.

Ri _n SiX ₄ - _{H (I)}

where n = 1, 2 or 3 or mixtures of these organosilanes, wherein RA is an unsaturated, mono- or polyunsaturated, monovalent, optionally halogenated, hydrocarbon radical having 1 to 24 carbon atoms and may be identical or different and X = halogen .

Nitrogen radical, OR ² , OCOR ² , O (CH ₂ ) _X OR ² , where R ^{2 is} hydrogen or a monovalent hydrocarbon radical having 1 to 12 carbon atoms and x = 1, 2, 3, or organosiloxane composed of units of the formula

(R ¹ 3Si0i / 2), and / or

(RlsiO _{_3/2)}

wherein RA has the above meaning, wherein the number of these units in an organosiloxane is at least 2, and I and II alone or in any mixtures in an amount of 0.003 mmol / g to 1.5 mmol / g per used silica surface of 100 m ² / g, preferably in an amount of 0.03 mmol / g to 0.9 mmol / g per silica surface used of 100 m ² / g and particularly preferably in an amount of 0.03 mmol / g to 0.3 mmol / g per silica surface used of 100 m ² / g, is silylated.

Examples of RA are alkyl radicals such as the methyl radical, the ethyl radical, propyl radicals such as the iso- or n-propyl radical, butyl radicals such as the t- or n-butyl radical, pentyl radicals such as neo, the iso- or n-pentyl radicals, hexyl radicals such as 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 the 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 phenyl, the biphenyl or naphthenyl radical, alkylaryl radicals such as benzyl, ethylphenyl, toluyl or xylyl radicals, halogenated alkyl radicals such as the 3-chloropropyl radical , the 3, 3, 3-trifluoropropyl or the perfluorohexylethyl radical, halogenated aryl radicals such as the chlorophenyl or chlorobenzyl radical.

Preferred examples of R - * - are the methyl radical, the octyl radical and the vinyl radical, particularly preferred is the methyl radical.

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 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. Preferred examples of R 1 are the methyl and ethyl radicals.

Examples of organosilanes are methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, methyltrimethoxysilane, dimethyldimethoxysilane, trimethylmethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, trimethylethoxysilane, Methyltriacethoxysilan, Dimethyldiacethoxysilan, Trimethylacethoxysilan, octylmethyldichlorosilane, octyl trichlorosilane, octadecylmethyldichlorosilane, octadecyltrichlorsilane, vinyltrichlorosilane,

Vinylmethyldichlorosilane, vinyldimethylchlorosilane, vinyltrimethoxysilane, vinylmethyldimethoxysilane, vinyldimethylmethoxysilane, vinyltriethoxysilane, vinylmethyldiethoxysilane, vinyldimethylethoxysilane, hexamethyldisilazane, divinyltetramethyldisilazane, bis (3, 3-trifluoropropyl) tetramethyldisilazane, octamethylcyclotetrasilazane, trimethylsilanol.

It is also possible to use any desired mixtures of organosilanes.

Mixtures of methylchlorosilanes on the one hand or alkoxysilanes and optionally disilazanes on the other hand are preferred.

Preference is given to methyltrichlorosilane, dimethyldichlorosilane and Trimethylchlorosilane or hexamethyldisilazane.

Examples of organosiloxanes are linear or cyclic dialkylsiloxanes having an average number of dialkylsiloxy units greater than 3. The dialkylsiloxanes are preferably dimethylsiloxanes. Particular preference is given to linear polydimethylsiloxanes having the following end groups: trimethylsiloxy, dimethylhydroxysiloxy, dimethylchlorosiloxy, methyldichlorosiloxy, dimethylmethoxysiloxy, methyldimethoxysiloxy, dimethylethoxysiloxy, methyldiethoxysiloxy, dimethylacethoxysiloxy, methyldiacethoxysiloxy, dimethylhydroxysiloxy, where the end groups may be identical or different. Particularly preferred among the polydimethylsiloxanes mentioned are those having a viscosity at 25 ^° C. of from 2 to 100 mPas and having the end groups trimethylsiloxy or dimethylhydroxysiloxy.

Further examples of organosiloxanes are liquid or soluble silicone resins, in particular those which contain methyl groups as the alkyl group.

Particularly preferred that R ^ 3 SiO] _ / 2 and _{SiO4 /} 2

Contain units or those containing R ^ -Siθ3 / 2 and optionally R ^ 2Siθ2 / 2 units. Here, R ^{1 is} preferably methyl.

In the case of organosiloxanes having a viscosity of greater than 1000 mPas, preference is given to those which are present in a technically usable solvent, such as, preferably, alcohols, such as methanol, ethanol, isopropanol, ethers, such as diethyl ether, tetrahydrofuran, siloxanes, such as hexamethyldisiloxane, alkanes, such as cyclohexane or n- Octane, aromatics such as toluene or xylene, with a concentration above 10% and a mixture viscosity less than 1000 mPas can be solved at shelf temperature. Preferred organosiloxanes are those which can be dissolved in a technically usable solvent (as defined above) with a concentration greater than 10% by weight and a mixture viscosity of less than 1000 mPas at the temperature of use.

Surface modification of particulate solids is performed to impart special surface properties, such as hydrophilicity or hydrophobicity, to improve adhesion between the particulate solid and polymer matrix, to enhance the rheological properties of particulate matter

To influence the dispersions

To control surface charge properties of particulate solids to improve the compatibility between particulate solid and polymer matrix and from a variety of others

Establish .

During surface modification, the particulate solids are preferably agitated, that is, stirred, agitated, or fluidized in a gas stream. Preference is given to mechanical fluidization by stirring.

During heating, the particulate solid is separated from the infrared lamp by a glass wall, and the infrared lamp may also preferably radiate into a glass cylinder containing the particulate solid, but may be any vessel through which infrared rays pass without being overly absorbed, quartz or Duranglas are therefore preferred.

The wavelengths of the radiant heaters are designed so that a minimum of energy in the reactor wall is converted into heat. As heating elements infrared radiators are used with a Heizwendeltemperatur of 1000 to 3000 ⁰ C, preferably with a Heizwendeltemperatur of 1500 to 3000 ⁰ C and particularly preferably with a Heizwendeltemperatur of 2000 to 2500 ⁰ C.

Preferably, the infrared radiator operates in a radiation range in which not more than 30%, preferably not more than 20% and particularly preferably not more than 15% of the radiant power within the glass is converted into heat.

For the reaction vessel, glasses are used which are not more than 30%, preferably not more than 20% and particularly preferably not more than 15% of the radiation power in the preferred wavelength range of the infrared radiator, i. the temperature range of the infrared radiator, to convert it into heat within the glass.

Durangläser and quartz glasses are preferably used.

Regulation of energy input:

The electric power of the infrared heating elements can only be controlled to a limited extent by voltage regulation down, since not only the heating power, but also the wavelength of the infrared heating elements would be larger when lowering the voltage, which in turn would result in a higher energy input into the reactor wall. In a larger control range so individual infrared radiator elements must be switched off or. Another object is a particle-warming device having an infrared radiator separated from the particles by glass.

The infrared radiator and the glass have the properties described above.

FIG. 1

FIG. 1 shows the particle heating device according to the invention as a sectional view.

In this case, the infrared radiator (1) in front of the glass wall (2), which separates the particles (3) from the infrared radiator (1).

example 1

In a continuous apparatus, consisting of a Belegungsbehalter with mechanical fluidization and Verdusungseinrichtung and a reaction vessel made of Duranglas with mechanical fluidization and externally mounted rod-shaped infrared radiators from Heraeus with a radiation power of 1400 W, at a temperature of 20 ° C under inert gas N2 to a Mass flow of 1000 g / h of hydrophilic KIESELSAURE, with a moisture content of less than 1% and an HCl content less than 100 ppm and with a specific surface area of 200 m ² / g (measured by the BET method according to DIN66131 and 66132) (available under the name WACKER HDK N20 at Wacker Chemie GmbH, Munich, D) 440 g / h of a methacryloxypropyltrimethoxysilane (available under the name WACKER Geniosil GF31 from Wacker Chemie GmbH, Munich, D) in liquid, finely divided form by evaporation over a single-substance nozzle (pressure 10 bar) inflicted. The so loaded silicic acid is required in the reaction vessel and at a residence time of 90 min. reacted at a temperature of 120 ⁰ C.

The analytical data of the silica are summarized in Table 1.

Example 2

In a continuous apparatus, consisting of a Belegungsbehalter with mechanical fluidization and Verdusungseinrichtung and a reaction vessel made of Duranglas with mechanical fluidization and externally mounted rod-shaped infrared radiators from Heraeus with a radiation power of 1400 W, at a temperature of 20 ⁰ C under inert gas N ₂ to a mass flow of 1000 g / h of hydrophilic KIESELSAURE, with a moisture content of less than 1% and an HCl content of less than 100 ppm and with a specific surface area of 150 m ² / g (measured by the BET method according to DIN66131 and 66132) (available under the WACKER HDK V15 at Wacker Chemie GmbH, Munich, D) 330 g / h of a methacryloxypropyltrimethoxysilane (available under the name WACKER Geniosil GF31 from Wacker Chemie GmbH, Munich, D) in liquid, finely divided form by evaporation over a single-substance nozzle (pressure 10 bar ) added. The thus loaded silicic acid is required in the reaction vessel and at a residence time of 90 min. reacted at a temperature of 120 ⁰ C.

Example 3

In a continuous apparatus, consisting of a Belegungsbehalter with mechanical fluidization and Verdusungseinrichtung and a reaction vessel made of Duranglas with mechanical fluidization and externally mounted rod-shaped infrared radiators Heraeus with a radiation power of 1400 W, are in a Temperature of 20 ⁰ C under inert gas N ₂ to a mass flow of 1000 g / h of hydrophilic KIESELSAURE, with a moisture content of less than 1% and an HCl content of less than 100 ppm and with a specific surface area of 300 m ² / g (measured by the BET Method according to DIN66131 and 66132) (obtainable under the name WACKER HDK T30 from Wacker Chemie GmbH, Munich, D) 660 g / h of a methacryloxypropyltrimethoxysilane (obtainable under the name WACKER Geniosil GF31 from Wacker Chemie GmbH, Munich, D) in liquid, extremely finely divided Form by Verdusen over a Einstoffduse (pressure 10 bar) added. The so loaded silicic acid is required in the reaction vessel and at a residence time of 45 min. reacted at a temperature of 120 ⁰ C.

TABLE 1 Analytical data of the silicas of Examples 1 to 3

Example% C tamped density g / l BET m2 / g

1 11, 0 73 98

2 8,4 96 75

3 16, 1 78 156

Description of the analysis methods

1. Carbon content (% C)

Elemental analysis on carbon; Burning the sample at over 1000 ⁰ C in the 0 ₂ stream, detection and quantification of the resulting CO ₂ with IR; Device LECO 244 2. Tamping density: According to DIN EN ISO 787-11 3. BET: According to DIN EN ISO 9277 / DIN 66131

Claims

claims

1. A process for heating particulate solids during surface modification, characterized in that the particulate solid is heated by means of an infrared lamp.

2. A process for heating particulate solids according to claim 1, characterized in that the infrared lamp is separated from the solid by glass.

3. A process for heating particulate solids according to claim 1 or 2, characterized in that not more than 30% of the radiant power is converted into heat within the glass.

4. A process for heating particulate solids according to one or more of claims 1 to 3, characterized in that it is the metal oxides in the solids.

5. A process for heating particulate solids as claimed in claim 4, characterized in that the metal oxide is silicic acid.

6. A process for heating particulate solids according to one or more of claims 1 to 5, characterized in that are used for surface modification of organosilicon compounds.

7. A process for heating particulate solids according to claim 6, characterized in that during the surface modification of the solid is moved.

8. particle heating device, characterized in that it comprises an infrared radiator (1) which is separated from the particles (3) by glass (2).

9. A particle heating device according to claim 8, characterized in that the infrared radiator (1) operates in a radiation range that not more than 15% of the radiant power within the glass (2) is converted into heat.