Abstract: A stable aquasol containing colloidal silica having a surface area of from about 700 m2/g to about 1100 m2/g, and an S-value of from about 20 to about 50; wherein the colloidal silica is not surface treated; wherein the molar ratio of SiO2/Na2O in the colloidal silica is greater than about 13.0:1 and is less than about 17.0:1; and wherein the aquasols have a percent by weight SiO2 solids level of from about 7.00 percent to about 16.80 percent is described and claimed.

Abstract: The present invention refers to a method of producing organically modified aerogels on a basis of silicon tetrachloride in which: a) a hydrogel is obtained by direct reaction of silicon tetrachloride with water, b) the hydrogel obtained in step a) is surface-modified, and c) the surface-modified gel obtained in step b) is dried.

Abstract: A silica sol-gel fabrication process is provided which allows improved control of the shrinkage that takes place during the drying of a gel body. In particular, the invention makes it possible to attain extremely low shrinkage through the completion of the drying stage, e.g., below 1% linear shrinkage, in relatively large sol-gel bodies of (dry weight) 1 kg or more, typically 10 kg or more, or even 40 kg or more, compared to the much higher shrinkages typically encountered. Specifically, use of a particular polymeric additive makes it possible for a gel body to experience linear shrinkage at least 55% less than an identical process without the polymeric additive.

Abstract: A process for producing a spherical silica gel, which comprises supplying a liquid mixture of an alkali silicate solution and an acid solution to a spraying apparatus, spraying the liquid mixture to obtain droplets, bringing the droplets into contact with a liquid for recovering a silica gel, and recovering the formed spherical silica gel together with the liquid for recovering a silica gel, as a slurry.

Abstract: A holographic light shaping diffuser (LSD) is formed from a monolithic glass material by recording light shaping structures (sometimes collectively known as “speckle”, particularly when the structures extend into the interior of the diffuser) in the glass material during its formation. A volume LSD may be produced by the photolithographic writing or other imaging of light shaping structures in a photosensitive glass material. Alternatively, a surface LSD may be produced by this imaging process or by embossing light shaping structures onto a high quality optical glass or by embossing a light shaping structures on a glass film layer coated onto a substrate. Both types of diffusers control the angular spread of transmitted light while homogenizing otherwise spatially noisy light sources such as LCDs and filamented light sources and while maintaining damage thresholds consistent with any glass optical element.

Abstract: Silica compositions for abrasive systems in dentifrice formulations are disclosed. The silica abrasive system comprises (a) silica gels having a median particle size below 7 microns, a pH of from about 6 to about 11 and powder RDA's of from 100 to about 200 and (b) silica gels or precipitates having a median particle size of 7 microns or greater and powder RDA's of from 50 to about 180. Silica (a) is preferably prepared by contacting a hydrous silica gel with an alkaline medium. Dentifrice compositions comprising the abrasive system has an RDA of 150 or less and PCR's of at least 80 and up to about 150, and an REA of less than about 30 (as measured on the IU scale).

Abstract: In a process for drying microporous, fluid-containing particles, the heat required for increasing the temperature is supplied by convection by reducing the interfacial tension of the fluid, preferably to 0 to 1/10, in particular to 0 to 1/20, of the interfacial tension of the fluid at room temperature, by appropriately increasing the temperature at from close to the critical pressure to supercritical pressure of the fluid. Furthermore, microporous, three-dimensionally networked particles are prepared by a process in which the drying process is used. In addition, an apparatus is used for carrying out the drying process, the apparatus comprising a pressure container having an inner container and pressure-withstanding outer container and suitable measuring and control apparatuses and pump apparatuses and heat exchangers, the inner container being provided for holding the particles to be dried and a gap being provided between the inner container and the outer container.

Abstract: Abrasive compositions comprised of water-insoluble abrasive polishing agents suspended in a liquid medium in combination with humectant, and methods for making same. The inventive abrasive compositions are rheologically stable, settling-resistant, and re-agglomeration resistant, even during and after transport and/or storage before end-use, such as incorporation into dentifrice formulations or other oral cleaning compositions. The high settling-resistance of the inventive abrasive composition makes it possible to avoid the need before end use for temporary stabilizers such as inorganic suspending agents (e.g., clays, fumed silicas) or organic binders (e.g., polysaccharides). Also, the abrasive compositions contain abrasive particles having improved brightness as compared to abrasive particles made via drying and dry comminution processing.

Abstract: Mesoporous materials containing a Group IIA metal are prepared by a sol-gel type techniques.

Abstract: Methods of making dentifrice compositions including, as a raw material ingredient thereof, abrasive compositions comprised of water-insoluble abrasive polishing agents suspended in a liquid medium in combination with humectant, and the unique dentifrice compositions made in this manner.

Abstract: In an epoxy resin composition comprising an epoxy resin, a curing agent, and an inorganic filler, the filler is porous silica having a specific surface area of 6-200 m2/g, a true specific gravity of 2.0-2.2, and a mean particle size of 2-50 &mgr;m. The epoxy resin composition is readily moldable, has a low moisture permeability and reliability in the cured state, and is suitable for forming a premolded hollow semiconductor package.

Abstract: This invention relates to bioactive sol-gel derived silica fibers, methods for their preparation, an implantable device comprising said fibers and the use of said device for tissue guiding or bone repair.

Abstract: The fine spherical silica having a particle size distribution in which maximum particle diameter is 24 &mgr;m, average particle diameter is 1.7 to 7 &mgr;m, and the proportion X1 of particles having a particle diameter of 3 &mgr;m or less in the total particles is 100/D50 to (18+100/D50) wt %, and the viscosity at 50° C. of a mixture obtained by blending a maximum of 80 wt % of the fine spherical silica with a liquid epoxy resin or silicone resin at room temperature is 20 Pa·s or less is provided. The spherical silica is useful as a filler for sealing resin composition which has excellent gap permeability and seals slight gaps, between a substrate and an IC chip and has high reliability.

Abstract: Fused silica stepper lens for photolithographic application is disclosed which is resistant to laser-induced damage, specifically, compaction or densification which can lead to an increase in the optical path length of the lens.

Abstract: A silica-water dispersion suitable for use as a sol for sol-gel fabrication is produced from a silica-water mixture with addition of alkaline agent. The agent functions to increase viscosity so as to improve dispersing efficiency during shear mixing.

Abstract: A process is described for making silica powder by a sol-gel process whereby an aqueous suspension is made of a silica-based raw material which includes particles containing chlorine, the pH of the suspension is adjusted to a value from 3 to 4.5 if necessary, the suspension is gelled, the gel obtained is dried and the dried gel is fractionated into silica granules. The silica-based raw material preferably includes particles containing chlorine having a specific surface area less than 80 m2/g and less than 5 wt. % relative to the total quantity of particles containing chlorine of silica particles having a specific surface area from 150 m2/g to 300 m2/g. The use of such powder to manufacture an optical fiber preform is also described.

Abstract: A dispersion comprising fine porous inorganic oxide particles, e.g., silica gel particles, wherein the particles have a median particle size below three microns. The dispersed particles have a porosity after drying in which at least about 0.50 cc/g of pore volume is from pores having a pore size of 600 Å or less as determined by nitrogen porosimetry. Embodiments prepared from silica gel have porosity after drying in which at least about 0.7 cc/g of pore volume is from pores having a diameter of 600 Å or smaller. The particles of the dispersion also can be described as having viscosity derived pore volume of at least about 0.5 g/cc. The dispersion is prepared by forming a dispersion from inorganic oxides having sufficient rigid structure to maintain porosity after milling and drying. After the inorganic oxide is selected, it is milled to have a median particle size of 0.05 to about 3 microns.

Abstract: A process for producing a linearly-miniaturized, densified optical product, which entails a) cold filling a mould with a liquid colloidal dispersion formed from a chemical precursor; b) polycondensing the liquid colloidal dispersion to obtain a gel; c) supercritically drying the gel to form an amorphous aerogel having dimensions corresponding to the mould; and d) isotropically miniaturizing the amorphous monolithic aerogel obtained.

Abstract: A method for stabilizing silica gel wherein after the gel is precipitated it is treated in a solution consisting of a liquid which is preferably water, aluminium sulphate and a compound such as a carbonate, hydroxide or oxide of a divalent metal.

Abstract: Disclosed are amorphous precipitated silicas, silica gels, and amorphous carbons derived from biomass and methods of producing them with and without adhered or deposited amorphous carbons produced by acidifying a caustic silicate solution produced by caustic digestion of biomass ash containing silica with and without activated carbon, the ash being obtained from thermal pyrolysis of the biomass, the acidifying effective to produce a slurry of the precipitated silica and silica gels with and without adhered or deposited amorphous carbon, and separated from the slurry the precipitated silicas and silica gels with and without the adhered or deposited amorphous carbons. The properties of the precipitated silica with adhered or deposited carbon being within the range as utilized in rubber compositions thereby avoiding the blending of silica and carbon components for such use.

Abstract: Disclosed are stable, aqueous colloidal silicas having surface area of greater than 700 m2/g and S-values of from 20-50. These colloidal silicas do not require treatment with surface treatment agents such as aluminum to achieve stability. These colloidal silica aquasols can be produced and stored at concentrations of greater than 7 percent by weight SiO2 solids, and even as high as 15 percent by weight solids or higher, and remain stable at room temperature for at least 30 days compared to art-known silica aquasols. These colloidal silica sols demonstrate advantageously improved performance over art-known colloidal silica sots in applications such as in drainage and retention in papermaking processes. Also disclosed are processes for making aqueous colloidal silicas of the invention and the use of such colloidal silicas in papermaking processes.

Abstract: Process for preparation of hydrophilic or partially hydrophilic inorganic aerogels. The invention relates to a process for the preparation of hydrophilic or partially hydrophilic inorganic aerogels, which comprises pyrolyzing a hydrophobic inorganic aerogel in the presence of oxygen at temperatures in the range from 100 to 1000° C.

Abstract: A sol-gel method of preparing a powder for use in forming a glass is provided, along with methods of preparing glasses and glass fibers from the powder. The inventive method allows for the incorporation of a wide range of elements and compositions into a homogeneous glass or glass fiber that is substantially free of hydroxide groups. In addition, dopants incorporated into glasses prepared by the inventive method are uniformly distributed throughout the glass structure.

Abstract: A method of producing a silica gel by hydrolyzing a silicon alkoxide and subjecting the resulting hydrogel to a hydrothermal treatment substantially without aging it is described.

Abstract: A multicomponent particulate gel includes 80-100 mole % SiO2, 1-10 mole % X2O, 1-10 mole % YO, 1-15 mole % Al2O3, and 0.1-5.0 weight % Er2O3,where X represents lithium, sodium, potassium, or mixtures thereof and Y represents calcium, barium, magnesium, lead or mixtures thereof, and the ratio of Al2O3 to (X2O+YO) is between about 0.9 and about 2.5. A process of manufacturing the gel includes hydrolyzing alkoxide derivatives of silicon, aluminum, erbium, lithium, sodium, potassium, calcium, barium, magnesium, lead or mixtures thereof in water to generate their respective hydroxide derivatives; polymerizing the hydroxide derivatives to produce a gel slurry comprising an essentially silica network; and drying the gel slurry to produce the gel.

Abstract: The present invention provides the amorphous silica particles having a double structure of a core of the dense amorphous silica and a shell of the bulky amorphous silica, having a volume-based median diameter of from 1 to 5 &mgr;m and containing not more than 10% by volume of fine particles having a particle diameter of not larger than 0.5 &mgr;m. The amorphous silica particles of the double structure have constant particle diameters not only in the powdery state but also in a state where they are blended in a coating material or in a resin, without developing fine particles, exhibit excellent delustering action and antiblocking action, exhibit decreased abrading property, and exhibit excellent resistance against scars or abrasion.

Abstract: Ultra-high temperature, light-weight, ceramic insulation such as ceramic tile is obtained by pyrolyzing a siloxane gel derived from the reaction of at least one organo dialkoxy silane and at least one tetralkoxy silane in an acid or base liquid medium. The reaction mixture of the tetra- and dialkoxy silanes may contain also an effective amount of a mono- or trialkoxy silane to obtain the siloxane gel. The siloxane gel is dried at ambient pressures to form a siloxane ceramic precursor without significant shrinkage. The siloxane ceramic precursor is subsequently pyrolyzed, in an inert atmosphere, to form the black ceramic insulation comprising atoms of silicon, carbon and oxygen. The ceramic insulation, can be characterized as a porous, uniform ceramic tile resistant to oxidation at temperatures ranging as high as 1700° C. and is particularly useful as lightweight tiles for spacecraft and other high-temperature insulation applications.

Abstract: A method of preparing mesoporous silica from a reaction mixture comprising a mineral acid such as HCl, an inorganic oxide source such as tetraethoxysilane, a surfactant such as cetyltrimethlyammonium bromide and water. The reaction mixture is mixed, e.g., by stirring or sonication, until sufficiently polymerized that mesostructured silica may be formed by a subsequent heating step, as indicated by the reaction mixture becoming opaque. This mixing is typically performed at room temperature for about 30-70 minutes. Then, the reaction mixture is heated in a pressurized vessel at a time, temperature and pressure sufficient to form mesostructured silica, e.g., at 60 to 230° C. for 15 to 80 minutes. Finally, mesoporous silica is recovered by filtering, drying and calcining in a furnace having a temperature in the range of 400 to 600° C. in air for at least 6 hours.

Abstract: A process for the preparation of mesostructured molecular sieve silicas from inorganic silicon precursors and polyoxyethylene oxide based polymers is described. The silicas are stable upon calcination to 600° to 800° C. The silicas are useful in refining processes.

Abstract: Disclosed are processes for producing gel composition which may be utilized to produce low density gel compositions without the need for supercritical drying, thermal treatment or surface treatment. The processes comprise drying a wet gel comprising gel solids and a drying agent to remove the drying agent while minimizing shrinkage of the gel during drying.

Abstract: A continuous process is provided for preparing silica microgels using carbon dioxide as a gel initiator at a pressure of at least about 172 kPa (about 25 psig). Consistent performance of microgel can be produced with varying production rates.

Abstract: It is an object of the present invention to obtain solid spherical silica particles having no depression or crack on the surface. The present invention provides a process for producing spherical silica particles, which comprises dispersing silica gel particles having an average particle size of from 0.05 to 3.0 &mgr;m in a mixed solution of an alkali silicate and an acid, spraying the dispersion to obtain droplets, and heating the droplets in a gas and gelating the mixed solution portion of an alkali silicate and an acid in the droplets.

Abstract: Disclosed is a method for fabricating high-purity silica glass using a sol-gel processing that includes the steps of: (a) mixing a deionized water with a fluorine compound and a dispersion agent to prepare an aqueous premix solution; (b) mixing the aqueous premix solution with a fumed silica; (c) mixing the resulting mixture to form a dispersed sol; (d) aging the sol at the ambient temperature to stabilize silica particles; and, (e) removing air voids from the sol and adding a gelation agent.

Abstract: A method for the preparation of hydrophilic silica gels with high pore volume. In the preferred method a hydrophilic silica hydrogel treated with an organosilicon compound to effect hydrophobing of the silica hydrogel is heated in the presence of an oxidizing atmosphere to a temperature sufficient to reduce the hydrophobicity imparted by the surface treatment thereby producing a hydrophilic silica gel having high pore volume.

Abstract: Macroporous ceramics were produced using the droplets of an emulsion as the templates around which the ceramic is deposited through a sol-gel process. Subsequent aging, drying and calcination yields a ceramic with pores in the range of 0.1 to several micrometers which have been left behind by the droplets. The unique deformability of the droplets prevents cracking and pulverization during processing and allows one to obtain porosities in excess of 74%. By starting with a monodisperse emulsion (produced through a repeated fractionation procedure) pores with a uniform and controllable size have been obtained. Self-assembly of these droplets into a colloidal crystal leads to ceramics which contain ordered arrays of pores. A wide range of porosities is obtainable with the advantages of low-temperature sol-gel processing, with a high degree of control and low cost.

Abstract: A synthetic quartz powder obtained by calcining a powder of silica gel, characterized in that white devitrification spots having sizes of larger than 20 &mgr;m in diameter formed in an ingot obtained by vacuum melting the synthetic quartz powder at a temperature of from 1780 to 1800° C. to form an ingot, followed by maintaining the ingot at a temperature of 1630° C. for 5 hours, are at most 10 spots/50 g.

Abstract: There is provided a process for producing an aerogel which comprises lowering a pH of a water glass solution to obtain a sol, gelling the sol to obtain a hydrogel, replacing water in the gel with an organic solvent, reacting the gel with a hydrophobilizing agent having hydrophobic groups as well as functional groups reactive with silanol groups in liquid phase, followed by supercritically drying; or hydrophobilizing and supercritically drying the resultant gel at the same time. Preferably, the hydrogel is prepared by ion exchanging alkali metals in the water glass solution using an ion exchange resin to obtain a sol which is subjected to suspension polymerization.

Abstract: The invention relates to a process for preparing organofunctionally modified aerogels by gelling a water glass by means of polycondensation and then converting it, by drying while retaining the structure of the gel, to give an aerogel, which process comprises reacting the gel, before drying, with an at least bifunctional organic compound, at least one functional group serving as a bond to the aerogel, while the remainder are retained, to aerogels which are obtainable by the novel process, and to their use.

Abstract: Precipitated silica, having the following physico-chemical parameters: BET surface area 120-300 m2/g CTAB surface area 100-300 m2/g BET/CTAB ratio 0.8-1.3 Sears index (consumption of 6-25 ml 0.1 N NaOH) DBP index 150-300 g/100 g wk coefficient <3.4 Particle size of the degraded <1.0 &mgr;m particles Particle size of the non- 1.0-100 &mgr;m degradable particles The precipitated silica is prepared by a process in which an alkali metal silicate (preferably soda water-glass) is reacted with mineral acids (preferably sulfuric acid) at temperatures of 60-95° C. at a pH of 7.0-11.0 with continuous stirring, the reaction is continued up to a solids concentration of 40 g-110 g, the pH is adjusted to a value between 3 and 5, and the precipitated silica is filtered off, washed, then dried and, if appropriate, ground or granulated.

Abstract: The present invention provides a method of preparing lipophilic silica in an aqueous medium in the absence of added acids, bases, or organic solvents. In particular, the present inventive method of preparing lipophilic silica comprises (a) providing a mixture consisting essentially of (i) at least one organically modified silica precursor which is a trifunctional silane, (ii) water, and (iii) at least one tetrafunctional silane, (b) allowing the organically modified silica to form in the mixture, and (c) removing the organically modified silica from the mixture.

Abstract: This invention relates to a rapid process for the preparation of a silica gel or a silicate polymer comprising contacting at least one fluoroalkoxysilane with a solution comprising water, optionally in the presence of a solvent and/or a catalyst. Low density gels can be prepared using this process and can possess large pore size, greater than 50 nm.

Abstract: The inventive process concerns the preparation of organically modified aerogels and their use.The process the invention comprises:a) introducing a siliceous lyogel or hydrogel,b) optionally subjecting the gel prepared in a) to complete or partial solvent exchange with an organic solvent,c) reacting the gel obtained in step a) or b) with at least one silylation agent,d) optionally washing the silylated gel obtained in step c) with an organic solvent, ande) drying the gel obtained in step c) or d) subcritically, which comprises reacting in step c) the gel obtained in step a) or b) with at least one chlorine-free silylation agent.

Abstract: Thermally insulative xerogels and their preparation are described. To obtain these xerogels, an inorganic gel having hydroxyl moieties is reacted with a silicon-nitrogen compound which has a C.sub.1-6 hydrocarbon moiety on the silicon. Shrinkage of the gel during drying the gel is reduced and a more highly porous xerogel is obtained. The more highly porous xerogel has a low thermal conductivity which makes it a good thermal insulation.

Abstract: The invention relates to a process for the preparation of aerogels having hydrophobic surface groups, consisting ofa) taking a silicate-type lyogel,b) optionally subjecting the lyogel taken in Step a) to a solvent exchange with another solvent,c) surface-modifying the gel obtained in Step a) or b) with at least one C.sub.1 -C.sub.6 -alcohol, andd) drying, under subcritical conditions, the surface-modified gel obtained in Step c).

Abstract: The invention concerns a process for preparing organically modified aerogels, in which a) a silicic acid sol with a pH .ltoreq.4.0 is produced from an aqueous potassium silicate solution using at least one organic and/or inorganic acid; b) the resultant silicic acid sol is polycondensed by the addition of a base to form SiO.sub.2 gel; c) the gel produced in step b) is washed with an organic solvent until the water content of the gel is .ltoreq.5 wt %; d) the gel obtained in step c) is surface-modified with at least one C.sub.1-6 alcohol; and e) the surface-modified which are difficult to dissolve in the silicic acid sol. Before step b), the resultant salts, which are difficult to dissolve, are precipitated to the greates possible extent and separated from the silicic acid sol.

Abstract: A process for producing a synthetic quartz powder, which comprises a step of heat-treating a silica gel powder while permitting it to flow in a rotary kiln.

Abstract: The invention relates to aerogels containing functional residues of the formula (I)--Y--Z, wherein Y is a straight-chained or branched alkylene group with 1 to 22 carbon atoms; Z is halogen, pseudohalogen, SR.sup.1, PR.sup.2 R.sup.3, colorant residue or metal complex residue; R.sup.1 is H, a straight-chained or branched alkyl group with 1 to 22 carbon atoms or an aryl group with 4 to 10 carbon atoms; and R.sup.2 and R.sup.3 are identical or different, a straight-chained or branched alkyl group with 1 to 22 carbon atoms, or an aryl group with 4 to 10 carbon atoms. The aerogels are suitable, for example, as catalyst stayes and/or sensors. They can be obtained by metal alcoholates and metal alcoholates in which at least one alcoholate residue is replaced by the --Y--Z group being converted into a lyogel by hydrolysis and condensation, and subsequently being dried.

Abstract: A wet silica gel can be prepared by a process comprising the steps of contacting a stable, aqueous, fluid, silica system having a pH greater than 7.5 with an ion exchange resin which removes metal ions and replaces them with H+ ions and thereby reduces the pH to less than 5.0, adding an organic liquid to the aqueous silica system, providing, however, that the organic liquid added stays in one phase with the aqueous, silica, system, and does not cause the silica to precipitate, and adding a base to the silica system so that the pH of the silica system is in the range of from about 5.0 to about 7.5, and allowing the wet silica gel to form. The wet silica gel formed by this process is characterized by its high organic solvent content and the low concentration of basic metal ions.

Abstract: A process for producing synthetic quartz powder which comprises calcining silica gel powder to produce a synthetic quartz glass powder, wherein dry air is used in the calcining process at least in the process of cooling from 800.degree. C. to 200.degree. C. This process enables efficient production of synthetic quartz glass powder on an industrial scale.

Abstract: Process for preparing porous spherical silica particles substantially consisting in emulsifying an acidic silica sol in a dispersing media, gelifying the microdrops of the sol in the emulsified state and submitting the resulting gel to thermal treatment in the presence of the emulsifier liquid and of sol gelation base.