CA2310317A1 - A method for the sub-critical drying of lyogels to produce aerogels - Google Patents
A method for the sub-critical drying of lyogels to produce aerogels Download PDFInfo
- Publication number
- CA2310317A1 CA2310317A1 CA002310317A CA2310317A CA2310317A1 CA 2310317 A1 CA2310317 A1 CA 2310317A1 CA 002310317 A CA002310317 A CA 002310317A CA 2310317 A CA2310317 A CA 2310317A CA 2310317 A1 CA2310317 A1 CA 2310317A1
- Authority
- CA
- Canada
- Prior art keywords
- drying
- fixed bed
- gel
- drying gas
- sub
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F26—DRYING
- F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
- F26B3/00—Drying solid materials or objects by processes involving the application of heat
- F26B3/02—Drying solid materials or objects by processes involving the application of heat by convection, i.e. heat being conveyed from a heat source to the materials or objects to be dried by a gas or vapour, e.g. air
- F26B3/06—Drying solid materials or objects by processes involving the application of heat by convection, i.e. heat being conveyed from a heat source to the materials or objects to be dried by a gas or vapour, e.g. air the gas or vapour flowing through the materials or objects to be dried
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B33/00—Silicon; Compounds thereof
- C01B33/113—Silicon oxides; Hydrates thereof
- C01B33/12—Silica; Hydrates thereof, e.g. lepidoic silicic acid
- C01B33/14—Colloidal silica, e.g. dispersions, gels, sols
- C01B33/157—After-treatment of gels
- C01B33/158—Purification; Drying; Dehydrating
- C01B33/1585—Dehydration into aerogels
Landscapes
- Chemical & Material Sciences (AREA)
- Dispersion Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Organic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Microbiology (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Inorganic Chemistry (AREA)
- Silicon Compounds (AREA)
- Drying Of Solid Materials (AREA)
- Colloid Chemistry (AREA)
Abstract
The present invention refers to a method for the sub-critical drying of lyogels to produce aerogels. The method for the sub-critical drying of lyogels to produce aerogels provides for the lyogel particles to be disposed as a fixed bed and for a drying gas to be passed through them.
Description
Description A method for the sub-critical drying of lyogels to produce aerogels The invention relates to a method for the sub-critical drying of iyogels to produce aerogds.
Lyogels are gels which cornain a liquid, the dispersing agent. In the partica~lar instance where the gel fluid is water, they are also referred to as hydrogels. In the present Application, the term'lyogel' also includes hydrogels. Aerogels in the wider sense, i.e. in the sense of "gel with air as the dispersant", a suitable gel is produced by drying. The term "aerogels" in this sense includes aerogels in the narrower sense, xerogels and cryogels.
In this respect, a dried gel is referred to as an aerogel in the narrower sense if the fluid of the gei is eliminated at temperatures above the critical temperature and starting from pressiu es which are above the critical pressure. On the other hand, if the fluid of the gel is reanoved sub-~tically, for e~ple with the formation of a fluid-vapour interface, then the resulting gel is also frequently refenred to as a xerogel.
VVhe~ the use of the te~cm serogels in the present Application is concerned, there are gels which are sub-critically dried.
Aemgds have a very low density and high porosity for solid substances.
Therefore, and on account of the minimal pore size, aerogels, particularly those with pomsities of over 60% arai densities below 0.6 g/cu.cm, display an exrranely low thermal conductivity and are therefore used as heat insulating materials such as are described for instance in EP-A
0 171 722.
For industrial applications, aerogels are predominamly used as Vie. For the application, it is in this respect essential for the aerogel granulate to be used to consist of particles of a suitable form, preferably spherical form, and size distribution.
Lyogels are gels which cornain a liquid, the dispersing agent. In the partica~lar instance where the gel fluid is water, they are also referred to as hydrogels. In the present Application, the term'lyogel' also includes hydrogels. Aerogels in the wider sense, i.e. in the sense of "gel with air as the dispersant", a suitable gel is produced by drying. The term "aerogels" in this sense includes aerogels in the narrower sense, xerogels and cryogels.
In this respect, a dried gel is referred to as an aerogel in the narrower sense if the fluid of the gei is eliminated at temperatures above the critical temperature and starting from pressiu es which are above the critical pressure. On the other hand, if the fluid of the gel is reanoved sub-~tically, for e~ple with the formation of a fluid-vapour interface, then the resulting gel is also frequently refenred to as a xerogel.
VVhe~ the use of the te~cm serogels in the present Application is concerned, there are gels which are sub-critically dried.
Aemgds have a very low density and high porosity for solid substances.
Therefore, and on account of the minimal pore size, aerogels, particularly those with pomsities of over 60% arai densities below 0.6 g/cu.cm, display an exrranely low thermal conductivity and are therefore used as heat insulating materials such as are described for instance in EP-A
0 171 722.
For industrial applications, aerogels are predominamly used as Vie. For the application, it is in this respect essential for the aerogel granulate to be used to consist of particles of a suitable form, preferably spherical form, and size distribution.
By virtue of their low density, however, aerogels also exhibit low mechanical stability, particularly in respect of sheer loadings and against abrasion.
By reason of the capillary forces which occur in sub-critical drying and the shrinkage involved, not all l5ro~gels are suitable for sub-aitical drying to produce an aemgel. During dryings the gel shrinks considerably if the meniscus of the fluid migrates imo the interior of the gel, in order, with effect from a certain point in the drying process, to spring back more or less completely into its staring form again. Consequently, depending upon the qualities of the inner gel , a certain minimum stability of the gel network is esse'nbal, modification of the inner gel surface often being required in order to prevent a reaction by adjacent pore walls in the sbtunk condition and a collapse of the gel which this would entail.
Corresponding processes in which the inner s<uface of an Si02 lyogel is organically modified and the resulting gel is sub-critically dried to produce an aerogel, are disclosed for example in US-A 5 565 142, DE-A-43 42 548 and in the unpublished German Patent Application 19648798.
Gels which are unsuitable for sub-critical drying collapse under ~b-critical drying, with a loss of the porous structure and therefore they no longer display the favourable properties of axrogels.
According to the gel, modification, granular form and size and drying conditions, so gel particles can, during drying, be destroyed on a macroscopic scale, i.e.
while r~simng the nanoporovs structure. It is true that the aerogel retains its properties but on aocoimt of the now smaller granular size an irregular or undefined grain shape, it can no longer be used so satisfactorily.
By reason of the capillary forces which occur in sub-critical drying and the shrinkage involved, not all l5ro~gels are suitable for sub-aitical drying to produce an aemgel. During dryings the gel shrinks considerably if the meniscus of the fluid migrates imo the interior of the gel, in order, with effect from a certain point in the drying process, to spring back more or less completely into its staring form again. Consequently, depending upon the qualities of the inner gel , a certain minimum stability of the gel network is esse'nbal, modification of the inner gel surface often being required in order to prevent a reaction by adjacent pore walls in the sbtunk condition and a collapse of the gel which this would entail.
Corresponding processes in which the inner s<uface of an Si02 lyogel is organically modified and the resulting gel is sub-critically dried to produce an aerogel, are disclosed for example in US-A 5 565 142, DE-A-43 42 548 and in the unpublished German Patent Application 19648798.
Gels which are unsuitable for sub-critical drying collapse under ~b-critical drying, with a loss of the porous structure and therefore they no longer display the favourable properties of axrogels.
According to the gel, modification, granular form and size and drying conditions, so gel particles can, during drying, be destroyed on a macroscopic scale, i.e.
while r~simng the nanoporovs structure. It is true that the aerogel retains its properties but on aocoimt of the now smaller granular size an irregular or undefined grain shape, it can no longer be used so satisfactorily.
Drying methods which at first sight appear obvious for such drying problems are not readily suited to major industrial production of aerogel granulate of a definite form.
By reason of tix low density of the aerogels, a fluid bed drying system has been found to be unsuited to major industrial production. In order not to carry the aerogel particles out of the layer, it would be necessary to work below the fluidising point; the necessary gas flow velocities would then be so low that there would be no guarantee of heat being supplied and vapour dispersed in an acceptable time for drying. Were greater gas flow velocities to be used, then the aerogel would not be complctely dried since it will be conveyed out of the dryer. Furthermore, in the fluidised phase, gel particles collide with one another so that there is considerable abrasion and grain fracture.
Contact drying to be not sufficiently effective since due to the high heat insulating capacity of the aerogels, a transfer of heat into layers more remote from the contact surface does not take place quickly enough so that only mi~mal layer' thicknesses and therefore, in view of the quantities need, excessively great surface areas would be needed.
In aooordance with DE-A-43 16 540, aerogels are dried by dielectric processes.
Due to tire necessary electtical anti the neladvely high investment for an appropriate drying apparatus, however, these methods are not sufficiently economical.
The'<efore, the obit of the present ion was to provide a method for the sub-critical drying of lyogels which are suitable for sub-critical drying to produce aerogels and which mitnrnises the destruction of aaogel particles and the abrasian of aerogel particles during drying and which can be used on a large industrial scale.
Surprisingly, the problem is resolved by a method for the sub-critical drying of lyogels to produce aerogels and which is characterised in that the lyogel particles are disposed as a static bed and have a dry gas flowing through them.
By reason of tix low density of the aerogels, a fluid bed drying system has been found to be unsuited to major industrial production. In order not to carry the aerogel particles out of the layer, it would be necessary to work below the fluidising point; the necessary gas flow velocities would then be so low that there would be no guarantee of heat being supplied and vapour dispersed in an acceptable time for drying. Were greater gas flow velocities to be used, then the aerogel would not be complctely dried since it will be conveyed out of the dryer. Furthermore, in the fluidised phase, gel particles collide with one another so that there is considerable abrasion and grain fracture.
Contact drying to be not sufficiently effective since due to the high heat insulating capacity of the aerogels, a transfer of heat into layers more remote from the contact surface does not take place quickly enough so that only mi~mal layer' thicknesses and therefore, in view of the quantities need, excessively great surface areas would be needed.
In aooordance with DE-A-43 16 540, aerogels are dried by dielectric processes.
Due to tire necessary electtical anti the neladvely high investment for an appropriate drying apparatus, however, these methods are not sufficiently economical.
The'<efore, the obit of the present ion was to provide a method for the sub-critical drying of lyogels which are suitable for sub-critical drying to produce aerogels and which mitnrnises the destruction of aaogel particles and the abrasian of aerogel particles during drying and which can be used on a large industrial scale.
Surprisingly, the problem is resolved by a method for the sub-critical drying of lyogels to produce aerogels and which is characterised in that the lyogel particles are disposed as a static bed and have a dry gas flowing through them.
Carried out in this way, the drying does not lead to grain fracture or abrasion since the particles are stationary in their bulls. Surprisingly, the drying can be carried out in relatively short times and in layer heights which are considerable for fixed bed drying.
In pdr~iple, any l5rog~ls which can be dried sub-critically are suitable for the method, i.e.
their gel structure must be sufficiently stable to withstand collapse of the framework by the action of capillary forces and are if necessary suitably surface modified in order for example to prevent a reaction between pore walls in the shnrnken condition.
Where the lyogels are concerned, these may according to the type of gel structure be organic or inorganic lyogels. For example, they can be produced on a basis of metal oxides which are Suitable for the Sol-gel technical (G. J. Brinker; G. W.
Scherer, Sol-Gel Science 1990, ct>apters 2 and 3), such as for example Si- or Al-compounds or on the basis of organic substances which are suitable for the sol-gel technique such as for example melamine formaldehyde condensates (US-A-5 086 085) or resorcin formaldehyde condo (US-A-4 873 218) or even on the basis of mixtures of the above-mentioned materials. Preferably, they are Si02 gels and particularly preferably organically surface modified Si02 gels such as are described for example in the unpublished German Patent Application No. 19648798.
Wliexe the gel fluid is von~ed, this may in principle be pure substances or mixtures, the gel fluid preferably comaining more than 50'/o by weight of organic solvents, preferably acetone or hexamethyl disiloxane. Naturally, the gel fluid may also contain small quantities of otl~r substances such as for example hydrochloric acid or residues of water.
The lyogel particles can in principle be of any desired form and size but preferably substantially spl~rica! particles with diameters between 100 um and 5 cm and particularly preferred are those with diameters between 0.5 mm and 5 mm. It is also possible to dry mixtures of particles of different shape and/or different size.
WO 99/32218 Ptr1'/EP98108244 In order to avoid already dried and therefore lightweight aerogel particles being blown away, it would among other things be necessary for the velocity of the dry gas flow to be low so that no dried aerogel particles are carried away. However, this results in low gas flows and therefore a very listed input. For drying aerogels, a rapid energy input is advamageous. For using relatively high drying gas flow velocities, the bulk must therefore, at those places where the gas flow emerges from the fixed bed, be limited by at least one arrangement which is permeable to the drying gas but not to the particles.
Surprisingly, the fixed bed is preferably and in per se known ma~mer, traversed by the drying gas flow passing through it downwards, so that the arrangement which is permeable to the drying gas but not to the particles is constituted by the carrier of the fixed bed. The drying apparatus which is then to be used is consequecitly not only simpler and less expensive but grain frachue is also reduced, since the upper layers which press down onto those underh are the first to be dried. The dried and mechanically sensitive aerogess then lie on the heavier and less dried and also mechanically loadable gel particles and are not heavily loaded mechanically.
For a continuous operation, the fixed bed may also be moved with the carrier, e.g. on a suitable belt. Preferably, the gas flow then passes through the fixed bed crosswise to the direction of movement.
The thickness of the fixed bed in the direction of flow of the drying gas stream can be surprisingly great. Preferably, it is between 20 cm and 100 cm and particularly preferably between 20 and 60 cm.
Any gas suitable for drying can be used as the drying gas; if the gel fluid comains large fiactions of organic solvents, then possibly an inert gas such as nitrogen should be used.
The input gas flow can already contain solvent gas which the process allows, in other words a ciradatory pattern of gas flow, whereby, as usual, solvent gas is constantly b eliminated from the circuit, for example by condensation. To accelerate the drying as a whole, it may be advarrtageous first to dry the gel in a circulatory fashion but to use fresh drying gas for drying the last residues of gel fluid.
The method aoco~ling to the invention can be carried out by apparatus known to the man skilled in the art, e.g. fiaoed bed driers, suitable containers with screen bottoms or suitable drying belts, etc., which may possibly be modified in a manner evident to a man of the art.
Preferably, the method for drying modified Si02 aerogds such as disclosed for example in DE-A-43 42 548 or in the unpublished German Patent Application 196 487 98 will be used.
In this case, if the gel fluid contains more than 50% by weight hexamethyl disiloxane or acetone, then the temperature of the drying gas is preferably between 100°C and 200°C
and with particxrlar preference between 140°C and 180°C.
In the case of the said surface modified Si02 aerogels, the incident flow velocities are pn~rably in the range between 1 and 40 curls and particularly preferably between 5 and 30 curls.
A)thaugh the method is particularly suitable for producing aerogels with densities below 300 glcu.cm, it is also possible to use it for drying xerogels of greater density.
The method aooording to the invention will be described hereinafter with reference to an example of embodiment but without however being limited thereby.
Example:
A modified Si02 lyogel which has been produced in accordance with examples 1 to 4 in the unpublished German Patent Application 1964877798 and which has a sharp grain see diction around 1 mm diameter is dried in a fixed bed with a height of 50 cm with a stream of nitrogen flowing through the fixed bed from the top downwards at an inad~t flow vdoc~y of 20 cxnls and with a gas inlet temperature of 160°C. L~itially, the gel is dried for 2'f~ hours in a circulatory manner, the drying Bas leaving the fixed bed saturated with moisture and after thorough condensation with a charge of lOglkg inert gas, it is again introduced into the fixed bed. Afterwards, drying is continued for half an-hour with fresh drying Bas. The dried aerogel displays virtually no grain fracture and hardly awy abrasion.
In pdr~iple, any l5rog~ls which can be dried sub-critically are suitable for the method, i.e.
their gel structure must be sufficiently stable to withstand collapse of the framework by the action of capillary forces and are if necessary suitably surface modified in order for example to prevent a reaction between pore walls in the shnrnken condition.
Where the lyogels are concerned, these may according to the type of gel structure be organic or inorganic lyogels. For example, they can be produced on a basis of metal oxides which are Suitable for the Sol-gel technical (G. J. Brinker; G. W.
Scherer, Sol-Gel Science 1990, ct>apters 2 and 3), such as for example Si- or Al-compounds or on the basis of organic substances which are suitable for the sol-gel technique such as for example melamine formaldehyde condensates (US-A-5 086 085) or resorcin formaldehyde condo (US-A-4 873 218) or even on the basis of mixtures of the above-mentioned materials. Preferably, they are Si02 gels and particularly preferably organically surface modified Si02 gels such as are described for example in the unpublished German Patent Application No. 19648798.
Wliexe the gel fluid is von~ed, this may in principle be pure substances or mixtures, the gel fluid preferably comaining more than 50'/o by weight of organic solvents, preferably acetone or hexamethyl disiloxane. Naturally, the gel fluid may also contain small quantities of otl~r substances such as for example hydrochloric acid or residues of water.
The lyogel particles can in principle be of any desired form and size but preferably substantially spl~rica! particles with diameters between 100 um and 5 cm and particularly preferred are those with diameters between 0.5 mm and 5 mm. It is also possible to dry mixtures of particles of different shape and/or different size.
WO 99/32218 Ptr1'/EP98108244 In order to avoid already dried and therefore lightweight aerogel particles being blown away, it would among other things be necessary for the velocity of the dry gas flow to be low so that no dried aerogel particles are carried away. However, this results in low gas flows and therefore a very listed input. For drying aerogels, a rapid energy input is advamageous. For using relatively high drying gas flow velocities, the bulk must therefore, at those places where the gas flow emerges from the fixed bed, be limited by at least one arrangement which is permeable to the drying gas but not to the particles.
Surprisingly, the fixed bed is preferably and in per se known ma~mer, traversed by the drying gas flow passing through it downwards, so that the arrangement which is permeable to the drying gas but not to the particles is constituted by the carrier of the fixed bed. The drying apparatus which is then to be used is consequecitly not only simpler and less expensive but grain frachue is also reduced, since the upper layers which press down onto those underh are the first to be dried. The dried and mechanically sensitive aerogess then lie on the heavier and less dried and also mechanically loadable gel particles and are not heavily loaded mechanically.
For a continuous operation, the fixed bed may also be moved with the carrier, e.g. on a suitable belt. Preferably, the gas flow then passes through the fixed bed crosswise to the direction of movement.
The thickness of the fixed bed in the direction of flow of the drying gas stream can be surprisingly great. Preferably, it is between 20 cm and 100 cm and particularly preferably between 20 and 60 cm.
Any gas suitable for drying can be used as the drying gas; if the gel fluid comains large fiactions of organic solvents, then possibly an inert gas such as nitrogen should be used.
The input gas flow can already contain solvent gas which the process allows, in other words a ciradatory pattern of gas flow, whereby, as usual, solvent gas is constantly b eliminated from the circuit, for example by condensation. To accelerate the drying as a whole, it may be advarrtageous first to dry the gel in a circulatory fashion but to use fresh drying gas for drying the last residues of gel fluid.
The method aoco~ling to the invention can be carried out by apparatus known to the man skilled in the art, e.g. fiaoed bed driers, suitable containers with screen bottoms or suitable drying belts, etc., which may possibly be modified in a manner evident to a man of the art.
Preferably, the method for drying modified Si02 aerogds such as disclosed for example in DE-A-43 42 548 or in the unpublished German Patent Application 196 487 98 will be used.
In this case, if the gel fluid contains more than 50% by weight hexamethyl disiloxane or acetone, then the temperature of the drying gas is preferably between 100°C and 200°C
and with particxrlar preference between 140°C and 180°C.
In the case of the said surface modified Si02 aerogels, the incident flow velocities are pn~rably in the range between 1 and 40 curls and particularly preferably between 5 and 30 curls.
A)thaugh the method is particularly suitable for producing aerogels with densities below 300 glcu.cm, it is also possible to use it for drying xerogels of greater density.
The method aooording to the invention will be described hereinafter with reference to an example of embodiment but without however being limited thereby.
Example:
A modified Si02 lyogel which has been produced in accordance with examples 1 to 4 in the unpublished German Patent Application 1964877798 and which has a sharp grain see diction around 1 mm diameter is dried in a fixed bed with a height of 50 cm with a stream of nitrogen flowing through the fixed bed from the top downwards at an inad~t flow vdoc~y of 20 cxnls and with a gas inlet temperature of 160°C. L~itially, the gel is dried for 2'f~ hours in a circulatory manner, the drying Bas leaving the fixed bed saturated with moisture and after thorough condensation with a charge of lOglkg inert gas, it is again introduced into the fixed bed. Afterwards, drying is continued for half an-hour with fresh drying Bas. The dried aerogel displays virtually no grain fracture and hardly awy abrasion.
Claims (12)
1. A method for the sub-critical drying of lyogels to produce aerogels, characterised in that the lyogel particles are disposed as a fixed bed and have drying as passed through them.
2. A method according to claim 1, characterised in that, at those locations at which the gas flow from the faced bed, the fixed bed is bounded by at least one arrangement which is permeable to the drying gas but not to the particles.
3. A method according to claim 2, characterised in that the fixed bed lies on the said means and has the flow passing through it from the top downwards.
4. A method according to at least one of claims 1 to 3, characterised in that the lyogel is an organically modified gel tire framework of which contains SiO2.
5. A method according to claim 4, characterised in that the gel fluid predominantly contains hexamethyl disiloxane.
6. A method according to claim 4, characterised in that the gel fluid predominantly contains acetone.
7. A method according to at least one of claims 4 to 6, characterised in that the temperature of the drying gas at the inlet is between 100°C and 200°C.
8. A method according to 6 or 7, characterised in that the incident flow velocity is between 1 cm/s and 40 cm/s.
9. A method according to at least one of the preceding claims, characterised in that the thickness of the fixed bed is between 20 cm and 100 cm in the direction of flow of the drying gas stream.
10. A method according to at least one of the preceding claims, characterised in that the drying gas follows a circulatory system.
11. A method according to at least one of the preceding claims, characterised in that in a first phase of drying the drying gas is circulated while in a second phase fresh drying gas is used.
12. A method according to at least one of the preceding claims, characterised in that the fixed bed is moved together with the means bounding it, the stream of drying gas being passed through the fixed bed crosswise to the direction of movement.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19756633A DE19756633A1 (en) | 1997-12-19 | 1997-12-19 | Lyogels and aerogels subcritically dried in a packed bed with minimal particle breakdown |
| DE19756633.2 | 1997-12-19 | ||
| PCT/EP1998/008244 WO1999032218A1 (en) | 1997-12-19 | 1998-12-16 | A method for the sub-critical drying of lyogels to produce aerogels |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2310317A1 true CA2310317A1 (en) | 1999-07-01 |
Family
ID=7852584
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002310317A Abandoned CA2310317A1 (en) | 1997-12-19 | 1998-12-16 | A method for the sub-critical drying of lyogels to produce aerogels |
Country Status (11)
| Country | Link |
|---|---|
| US (1) | US6378229B1 (en) |
| EP (1) | EP1042059B1 (en) |
| JP (1) | JP4450989B2 (en) |
| KR (1) | KR100523465B1 (en) |
| CN (1) | CN1111445C (en) |
| AU (1) | AU2273799A (en) |
| BR (1) | BR9813736A (en) |
| CA (1) | CA2310317A1 (en) |
| DE (2) | DE19756633A1 (en) |
| ES (1) | ES2191989T3 (en) |
| WO (1) | WO1999032218A1 (en) |
Families Citing this family (20)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19648798C2 (en) * | 1996-11-26 | 1998-11-19 | Hoechst Ag | Process for the production of organically modified aerogels by surface modification of the aqueous gel (without prior solvent exchange) and subsequent drying |
| US7005181B2 (en) | 2000-04-06 | 2006-02-28 | American Aerogel Corporation | Organic, open cell foam materials, their carbonized derivatives, and methods for producing same |
| US20020009585A1 (en) * | 2000-04-06 | 2002-01-24 | Albert Donald F. | Organic, low density microcellular materials, their carbonized derivatives, and methods for producing same |
| EP1406958A1 (en) * | 2001-03-16 | 2004-04-14 | American Aerogel Corporation | Organic, open cell foam materials |
| AU2002213437C1 (en) * | 2001-10-04 | 2008-09-04 | American Aerogel Corporation | Organic, open cell foam materials |
| DE102005014291A1 (en) * | 2005-03-24 | 2006-09-28 | Basf Ag | Process for the preparation of water-absorbing polymers |
| ITLE20050008A1 (en) * | 2005-05-24 | 2006-11-25 | Megatex S P A | YARNS OF NATURAL AND SYNTHETIC ORIGIN WITH BARRIER CHARACTERISTICS OF HEAT TRANSPORT OBTAINED THROUGH THE AEROGEL DEPOSITION. |
| JP5167263B2 (en) * | 2006-09-19 | 2013-03-21 | ビーエーエスエフ ソシエタス・ヨーロピア | Method for producing color-stable water-absorbing polymer particles having a low degree of neutralization |
| US7750056B1 (en) | 2006-10-03 | 2010-07-06 | Sami Daoud | Low-density, high r-value translucent nanocrystallites |
| WO2009140030A2 (en) | 2008-05-15 | 2009-11-19 | Arizona Board Of Regents For And On Behalf Of Arizona State University | Porous metal oxide particles |
| WO2011046910A2 (en) | 2009-10-14 | 2011-04-21 | Arizona Board Of Regents For And On Behalf Of Arizona State University | Fabricating porous materials using thixotropic gels |
| US9242900B2 (en) | 2009-12-01 | 2016-01-26 | Arizona Board Of Regents, A Body Corporate Of The State Of Arizona Acting For And On Behalf Of Arizona State University | Porous geopolymer materials |
| US9365691B2 (en) | 2010-08-06 | 2016-06-14 | Arizona Board Of Regents, A Body Corporate Of The State Of Arizona Acting For And On Behalf Of Arizona State University | Fabricating porous materials using intrepenetrating inorganic-organic composite gels |
| CN103946181A (en) | 2011-09-21 | 2014-07-23 | 亚利桑那州立大学董事会(代理及代表亚利桑那州立大学的法人团体) | Geopolymer resin materials, geopolymer materials, and materials produced thereby |
| FR2981341B1 (en) | 2011-10-14 | 2018-02-16 | Enersens | PROCESS FOR MANUFACTURING XEROGELS |
| WO2015006010A2 (en) | 2013-06-21 | 2015-01-15 | Dong-Kyun Seo | Metal oxides from acidic solutions |
| US10926241B2 (en) | 2014-06-12 | 2021-02-23 | Arizona Board Of Regents On Behalf Of Arizona State University | Carbon dioxide adsorbents |
| DE102015207945A1 (en) * | 2015-04-29 | 2016-11-03 | Wacker Chemie Ag | Hydrophobic aerogels with low occupancy of monofunctional units |
| US10829382B2 (en) | 2017-01-20 | 2020-11-10 | Skysong Innovations | Aluminosilicate nanorods |
| EP3762137A1 (en) * | 2018-03-05 | 2021-01-13 | Evonik Operations GmbH | Method for producing an aerogel material |
Family Cites Families (84)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE296898C (en) | ||||
| DE261581C (en) | 1912-01-17 | 1913-06-25 | Krupp Ag | Impact detonator with a delay that can be switched on and off |
| US2093454A (en) | 1934-10-01 | 1937-09-21 | Samuel S Kistler | Method of producing aerogels |
| US2385217A (en) | 1942-10-09 | 1945-09-18 | Socony Vacuum Oil Co Inc | Gel pellets |
| GB607234A (en) | 1946-01-15 | 1948-08-27 | Standard Oil Dev Co | Improved process for the preparation of gel particles |
| NL74665C (en) | 1949-04-07 | |||
| GB682574A (en) | 1950-05-04 | 1952-11-12 | Dow Corning Ltd | Improvements in or relating to silica compositions |
| US2680696A (en) | 1951-02-14 | 1954-06-08 | Du Pont | Method of esterifying the surface of a silica substrate having a reactive silanol surface |
| US2786042A (en) | 1951-11-23 | 1957-03-19 | Du Pont | Process for preparing sols of colloidal particles of reacted amorphous silica and products thereof |
| US2886460A (en) | 1954-09-14 | 1959-05-12 | Du Pont | Organophilic and hydrophilic composition |
| US3015645A (en) | 1954-10-06 | 1962-01-02 | Dow Corning | Silica powders |
| GB783868A (en) | 1954-10-06 | 1957-10-02 | Midland Silicones Ltd | A process of preparing hydrophobic organo-silicon powders |
| US2978298A (en) | 1956-09-04 | 1961-04-04 | Gen Electric | Process for producing hydrophobic aerogels |
| US3122520A (en) | 1959-10-05 | 1964-02-25 | Dow Corning | Method of making silicone rubber fillers |
| US3024126A (en) | 1960-06-15 | 1962-03-06 | Dow Corning | Method of treating reinforcing silica |
| SE319161B (en) | 1968-01-30 | 1970-01-12 | Fosfatbolaget Ab | |
| US3794713A (en) | 1968-08-06 | 1974-02-26 | Nat Petro Chem | Preparation of silica gels |
| DE2103243C3 (en) | 1971-01-25 | 1979-01-11 | Basf Ag, 6700 Ludwigshafen | Process and device for the production of largely spherical, silica-containing hydrogels |
| US4101442A (en) | 1976-06-01 | 1978-07-18 | Union Carbide Corporation | Non-aqueous antifoam compositions |
| US4101443A (en) | 1976-06-01 | 1978-07-18 | Union Carbide Corporation | Transient antifoam compositions |
| US4190457A (en) | 1978-06-09 | 1980-02-26 | Phillips Petroleum Co. | Preparation of inorganic xerogels |
| CS208879B1 (en) | 1979-07-09 | 1981-10-30 | Ivan Novak | Preparation method of silicic acid xerogel with high volumen of pores |
| DE2951577A1 (en) | 1979-12-21 | 1981-07-02 | Grünzweig + Hartmann und Glasfaser AG, 6700 Ludwigshafen | METHOD FOR PRODUCING HEAT-INSULATING BODIES AND DEVICE FOR IMPLEMENTING THE METHOD |
| US4344800A (en) | 1980-06-03 | 1982-08-17 | Dow Corning Corporation | Method for producing hydrophobic reinforcing silica fillers and fillers obtained thereby |
| DE3329016A1 (en) | 1983-08-11 | 1985-02-28 | Basf Ag, 6700 Ludwigshafen | METHOD FOR PRODUCING POLYMERISATES OF ETHYLENE BY MEANS OF A SILICONE XEROGEL / CHROMTRIOXIDE CATALYST |
| DE3429671A1 (en) | 1984-08-11 | 1986-02-20 | Basf Ag, 6700 Ludwigshafen | METHOD FOR PRODUCING AEROGELS |
| JPS6169867A (en) | 1984-09-13 | 1986-04-10 | Mitsubishi Rayon Co Ltd | Resin composition containing fine silica particle |
| US4649037A (en) | 1985-03-29 | 1987-03-10 | Allied Corporation | Spray-dried inorganic oxides from non-aqueous gels or solutions |
| FR2584698B1 (en) | 1985-07-15 | 1990-05-18 | Rhone Poulenc Spec Chim | PROCESS FOR THE PREPARATION OF SPHEROIDAL SILICA PARTICLES |
| US5215733A (en) | 1986-04-25 | 1993-06-01 | Unilever Patent Holdings B.V. | Manufacture of silica gels using shear to reduce the particle size prior to washing with a hydrocyclone |
| US4888369A (en) | 1987-01-21 | 1989-12-19 | Himont Incorporated | Polypropylene composition resistant to high energy radiation, and radiation sterilized articles therefrom |
| FR2613708B1 (en) | 1987-04-13 | 1990-10-12 | Rhone Poulenc Chimie | HYDROPHOBIC PRECIPITATION SILICA, ITS PREPARATION PROCESS AND ITS APPLICATION TO THE REINFORCEMENT OF SILICON ELASTOMERS |
| US5001183A (en) | 1987-09-10 | 1991-03-19 | Dow Corning Corporation | Method of hydrophobing silica |
| US4950502A (en) | 1987-09-10 | 1990-08-21 | Dow Corning Corporation | Method of hydrophobing silica |
| US4873218A (en) | 1988-05-26 | 1989-10-10 | The United States Department Of Energy | Low density, resorcinol-formaldehyde aerogels |
| JPH02152196A (en) | 1988-12-03 | 1990-06-12 | Osaka Prefecture | Distributed el element |
| DE3914850A1 (en) | 1989-05-05 | 1990-11-08 | Basf Ag | THERMAL INSULATING MATERIAL BASED ON PIGMENT-BASED SILICONE ACULATE ARRAY |
| US5156895A (en) * | 1990-01-26 | 1992-10-20 | Thermalux, A Limited Partnership | Monolithic aerogel insulation cast and dried within a support structure and method |
| EP0497966B1 (en) | 1990-08-23 | 1997-10-29 | THE REGENTS OF THE UNIVERSITY OF CALIFORNIA as represented by Lawrence Livermore National Laboratory | A METHOD FOR PRODUCING METAL OXIDE AEROGELS HAVING DENSITIES LESS THAN 0.02 g/cm?3 |
| US5409683A (en) | 1990-08-23 | 1995-04-25 | Regents Of The University Of California | Method for producing metal oxide aerogels |
| JP2646150B2 (en) | 1990-08-27 | 1997-08-25 | 出光興産 株式会社 | Water repellent silica sol and method for producing the same |
| US5674962A (en) | 1990-11-30 | 1997-10-07 | Mitsubishi Rayon Company Ltd. | Toner resin |
| US5081163A (en) | 1991-04-11 | 1992-01-14 | The United States Of America As Represented By The Department Of Energy | Melamine-formaldehyde aerogels |
| NO912006D0 (en) | 1991-05-24 | 1991-05-24 | Sinvent As | PROCEDURE FOR THE MANUFACTURE OF A SILICA-AEROGEL-LIKE MATERIAL. |
| DE4201306A1 (en) | 1992-01-20 | 1993-07-22 | Basf Ag | MOLDED PARTS OR PANELS FROM SILICA AEROGELS |
| US5565142A (en) | 1992-04-01 | 1996-10-15 | Deshpande; Ravindra | Preparation of high porosity xerogels by chemical surface modification. |
| DE4231749A1 (en) | 1992-09-23 | 1994-03-24 | Basf Ag | Process for the preparation of a supported catalyst for the polymerization of alpha-olefins |
| US5420168A (en) | 1993-04-01 | 1995-05-30 | The Regents Of The University Of California | Method of low pressure and/or evaporative drying of aerogel |
| DE4316540A1 (en) | 1993-05-18 | 1994-11-24 | Hoechst Ag | Process for subcritical drying of aerogels |
| US5508341A (en) | 1993-07-08 | 1996-04-16 | Regents Of The University Of California | Organic aerogel microspheres and fabrication method therefor |
| EP0710262B1 (en) | 1993-07-22 | 2000-06-14 | Huntsman ICI Chemicals LLC | Organic aerogels |
| US5484818A (en) | 1993-07-22 | 1996-01-16 | Imperial Chemical Industries Plc | Organic aerogels |
| AU7655594A (en) | 1993-08-31 | 1995-03-22 | Basf Aktiengesellschaft | Hydrophobic silicic acid aerogels |
| JP2725573B2 (en) | 1993-11-12 | 1998-03-11 | 松下電工株式会社 | Manufacturing method of hydrophobic airgel |
| DE4342548A1 (en) | 1993-12-14 | 1995-06-22 | Hoechst Ag | Xerogels, processes for their manufacture and their use |
| DE4404701A1 (en) | 1994-02-15 | 1995-08-17 | Hoechst Ag | Composite foams, processes for their production and their use |
| US5494858A (en) | 1994-06-07 | 1996-02-27 | Texas Instruments Incorporated | Method for forming porous composites as a low dielectric constant layer with varying porosity distribution electronics applications |
| US5473826A (en) * | 1994-08-19 | 1995-12-12 | Yazaki Corporation | Process for drying sol-gel derived porous bodies at elevated subcritical temperatures and pressures |
| DE4430669A1 (en) | 1994-08-29 | 1996-03-07 | Hoechst Ag | Process for the production of fiber-reinforced xerogels and their use |
| US5476878A (en) | 1994-09-16 | 1995-12-19 | Regents Of The University Of California | Organic aerogels from the sol-gel polymerization of phenolic-furfural mixtures |
| DE4437424A1 (en) | 1994-10-20 | 1996-04-25 | Hoechst Ag | Airgel-containing composition, process for its preparation and its use |
| DE4439217A1 (en) | 1994-11-03 | 1996-05-09 | Hoechst Ag | Process for the production of aerogels |
| CN1060749C (en) | 1994-11-23 | 2001-01-17 | 卡伯特公司 | Composite material containing aerogel, process for manufacturing said material and use thereof |
| DE4441567A1 (en) | 1994-11-23 | 1996-05-30 | Hoechst Ag | Airgel-containing composite material, process for its production and its use |
| KR100368851B1 (en) | 1994-12-21 | 2003-05-12 | 캐보트 코포레이션 | Composites consisting of one or more layers of fibrous webs and airgel particles |
| DE19502453C1 (en) | 1995-01-27 | 1996-09-05 | Hoechst Ag | Process for the production of modified Si0¶2¶ aerogels and their use |
| DE19506141A1 (en) | 1995-02-22 | 1996-08-29 | Hoechst Ag | Use of aerogels in pharmacy, cosmetics and crop protection |
| DE19525021A1 (en) | 1995-07-10 | 1997-01-16 | Hoechst Ag | Process for the production of organically modified aerogels and their use |
| DE19533564A1 (en) | 1995-09-11 | 1997-03-13 | Hoechst Ag | Fibrous airgel composite material |
| CA2231538A1 (en) | 1995-09-11 | 1997-03-20 | Hoechst Research & Technology Deutschland Gmbh & Co. Kg | Composite material containing aerogel and an adhesive, a process for manufacturing the same, and the use thereof |
| DE19534198A1 (en) | 1995-09-15 | 1997-03-20 | Hoechst Ag | Process for the production of organofunctionalized aerogels |
| DE19537821A1 (en) | 1995-10-11 | 1997-04-17 | Hoechst Ag | Coated film used for thermal insulation, electronic applications, noise absorption or membranes |
| US5595593A (en) | 1995-10-12 | 1997-01-21 | Dow Corning Corporation | Treatment of fillers with oxa-silacycloalkanes |
| DE19541279A1 (en) | 1995-11-06 | 1997-05-07 | Hoechst Ag | Process for the production of organically modified aerogels using alcohols |
| DE19541715A1 (en) | 1995-11-09 | 1997-05-15 | Hoechst Ag | Process for the production of organically modified aerogels, in which the salts formed are precipitated |
| DE19541992A1 (en) | 1995-11-10 | 1997-05-15 | Hoechst Ag | Process for the production of organically modified aerogels using alcohols, in which the salts formed are precipitated |
| US5680713A (en) * | 1996-03-05 | 1997-10-28 | Hoechst Aktiengesellschaft | Process for the subcritical drying of aerogels |
| DE19631267C1 (en) | 1996-08-02 | 1998-04-30 | Hoechst Ag | Process for the production of organically modified aerogels |
| DE19648798C2 (en) | 1996-11-26 | 1998-11-19 | Hoechst Ag | Process for the production of organically modified aerogels by surface modification of the aqueous gel (without prior solvent exchange) and subsequent drying |
| US5750610A (en) | 1997-02-24 | 1998-05-12 | Dow Corning Corporation | Hydrophobic organosilicate-modified silica gels |
| US5708069A (en) | 1997-02-24 | 1998-01-13 | Dow Corning Corporation | Method for making hydrophobic silica gels under neutral conditions |
| AU2105499A (en) | 1998-01-15 | 1999-08-02 | Cabot Corporation | Polyfunctional organosilane treatment of silica |
| US6099792A (en) * | 1998-10-07 | 2000-08-08 | Yazaki Corporation | Sol-gel process using porous mold |
| US6258305B1 (en) * | 1999-03-29 | 2001-07-10 | Sandia Corporation | Method for net-shaping using aerogels |
-
1997
- 1997-12-19 DE DE19756633A patent/DE19756633A1/en not_active Withdrawn
-
1998
- 1998-12-16 BR BR9813736-0A patent/BR9813736A/en not_active IP Right Cessation
- 1998-12-16 CA CA002310317A patent/CA2310317A1/en not_active Abandoned
- 1998-12-16 AU AU22737/99A patent/AU2273799A/en not_active Abandoned
- 1998-12-16 KR KR10-2000-7005717A patent/KR100523465B1/en not_active IP Right Cessation
- 1998-12-16 JP JP2000525200A patent/JP4450989B2/en not_active Expired - Lifetime
- 1998-12-16 CN CN98812438A patent/CN1111445C/en not_active Expired - Lifetime
- 1998-12-16 EP EP98966343A patent/EP1042059B1/en not_active Expired - Lifetime
- 1998-12-16 DE DE69811948T patent/DE69811948T2/en not_active Expired - Lifetime
- 1998-12-16 WO PCT/EP1998/008244 patent/WO1999032218A1/en active IP Right Grant
- 1998-12-16 ES ES98966343T patent/ES2191989T3/en not_active Expired - Lifetime
-
2000
- 2000-06-14 US US09/594,000 patent/US6378229B1/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| EP1042059A1 (en) | 2000-10-11 |
| KR100523465B1 (en) | 2005-10-24 |
| DE69811948D1 (en) | 2003-04-10 |
| DE69811948T2 (en) | 2003-11-13 |
| JP2001526107A (en) | 2001-12-18 |
| DE19756633A1 (en) | 1999-06-24 |
| JP4450989B2 (en) | 2010-04-14 |
| US6378229B1 (en) | 2002-04-30 |
| BR9813736A (en) | 2000-10-10 |
| WO1999032218A1 (en) | 1999-07-01 |
| EP1042059B1 (en) | 2003-03-05 |
| KR20010032475A (en) | 2001-04-25 |
| AU2273799A (en) | 1999-07-12 |
| CN1111445C (en) | 2003-06-18 |
| CN1282270A (en) | 2001-01-31 |
| ES2191989T3 (en) | 2003-09-16 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA2310317A1 (en) | A method for the sub-critical drying of lyogels to produce aerogels | |
| Syahrul et al. | Energy analysis in fluidized‐bed drying of large wet particles | |
| EP0123293B1 (en) | Process for preparing superficially porous supports for chromatography and catalysts | |
| KR20010041767A (en) | Method for drying and producing microporous particles | |
| EP3319998B1 (en) | Amine-functionalized fibrillated cellulose for co2 adsorption and methods for making same | |
| CN107849348A (en) | Aerogel material and its production method | |
| JP2001518875A (en) | Method for producing low-density gel structure | |
| US6438867B1 (en) | Method for drying and producing microporous particles and a drying device | |
| US6267942B1 (en) | Method for producing spherical silica particles | |
| AU781513B2 (en) | Method for drying paste-like materials | |
| Aubin et al. | Modeling and simulation of drying operations in PVC powder production line: Experimental and theoretical study of drying kinetics on particle scale | |
| Sachio et al. | Effects of surface resistances on simultaneous heat and mass transfer in porous solids with phase change | |
| CN104445224B (en) | A kind of preparation method of fine silicon dioxide aerogel powder | |
| CN109046187A (en) | A kind of gas-solid fluidized bed reactor of high inflation rate, the method and its application for realizing high inflation rate in a fluidized bed | |
| Nagahashi et al. | Enhancement of large‐particle gas‐fluidization by adding liquid | |
| Guo et al. | Drying of microparticle slurry and salt-water solution by a powder-particle spouted bed | |
| US5447624A (en) | Packings for liquid chromatography and process for producing the same | |
| KR101900265B1 (en) | Apparatus for Drying Fine Particles | |
| JP2006273930A (en) | Particulate formed body carrying functional particle and its manufacturing process | |
| KR920016512A (en) | Drying method of finely ground foamable styrene polymer | |
| KR20200133768A (en) | Metahaloisite powder and method for producing metahaloisite powder | |
| US3492792A (en) | Process and apparatus for gas chromatography | |
| KR20010013060A (en) | Method for producing substantially globular lyogels and aerogels | |
| RU2181693C1 (en) | Method of dewatering of solutions of calcium and magnesium chlorides | |
| MXPA99009993A (en) | Method for granulating aerogels |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Discontinued |