The Inorganic Material Primarily Contains Compounds Containing Both Silicon And Oxygen, Or Both Aluminum And Oxygen, Or Combinations Thereof (e.g., Silica (sio2) Organosol*, Silica Alcosol, Talc, Clay) Patents (Class 516/34)
  • Patent number: 6846435
    Abstract: The present invention relates to a process for preparing metal oxides or metal aquoxides, especially alumina hydrates which can be dispersed in organic solvents, and to sulfonic acid-modified metal oxides or metal aquoxides that can be prepared by this process.
    Type: Grant
    Filed: July 6, 2000
    Date of Patent: January 25, 2005
    Assignee: Sasol Germany GmbH
    Inventors: Frank Michael Bohnen, Katja Siepen, Paul K. Hurlburt, Karen Reitz
  • Publication number: 20040248995
    Abstract: Hybrid sol comprising [SiOx(OH)y]n particles, where 0<y<4 and 0<x<2, which consist of a mixture of a first fraction of particles having a particle size of 4-15 nm and a second fraction of particles having a mean particle size of 15-60 nm, water and a solvent; obtainable by hydrolytic polycondensation of tetraalkoxysilanes in an aqueous, solvent-containing medium with addition of a monodisperse silicon oxide hydroxide sol having a mean particle size of 15-60 nm and a maximum standard deviation of 20%, and the preparation and use thereof.
    Type: Application
    Filed: March 19, 2004
    Publication date: December 9, 2004
    Inventors: Walther Glaubitt, Monika Kursawe, Andreas Gombert, Thomas Hofmann
  • Patent number: 6806295
    Abstract: Methods for sol-gel processing that generally involve mixing together an inorganic metal salt, water, and a water miscible alcohol or other organic solvent, at room temperature with a macromolecular dispersant material, such as hydroxypropyl cellulose (HPC) added. The resulting homogenous solution is incubated at a desired temperature and time to result in a desired product. The methods enable production of high quality sols and gels at lower temperatures than standard methods. The methods enable production of nanosize sols from inorganic metal salts. The methods offer sol-gel processing from inorganic metal salts.
    Type: Grant
    Filed: September 17, 1999
    Date of Patent: October 19, 2004
    Assignee: UT-Battelle, LLC
    Inventor: Zhong-Cheng Hu
  • Patent number: 6787575
    Abstract: The invention relates to the technological sector of mineral fillers used in the sector which manufactures polyurethane foams and in particular fillers of the carbonate, hydroxide, silicate, sulphate type and similar mineral fillers. The invention relates in particular to a method of treating mineral fillers of a specific grain size with the aid of treatment agents of the organic phosphate type, incorporating a de-agglomeration step, and optionally a selection step, with a view to improving the techniques used to manufacture polyurethane foams either by foaming without an auxiliary blowing agent or with a blowing agent such as CO2, and composite polyurethane, whilst reducing the time needed to mix this treated filler treated with the polyol and other reagents. Numerous applications for block foams or moulded foams, for mattresses and similar, the automotive industry, various industrial components, etc . . .
    Type: Grant
    Filed: May 14, 2001
    Date of Patent: September 7, 2004
    Assignee: Omya SA
    Inventors: Jean Pierre Fichou, Maurice Husson, Georges Ravet, Pierre Blanchard
  • Patent number: 6716523
    Abstract: A dispersant slurry for making spandex, based on phosphated block poly(alkylsiloxane)-poly(alkyleneether) alcohol or aromatic- or alkylaromatic-terminated phosphated poly(alkyleneether) alcohol dispersants, is provided.
    Type: Grant
    Filed: January 6, 2003
    Date of Patent: April 6, 2004
    Assignee: E. I. du Pont de Nemours and Co.
    Inventors: Thomas Edward Carney, Oliver Gutsche, Kai-Volker Schubert
  • Patent number: 6706795
    Abstract: The present invention relates to a method for the production of particles of nano-materials being transition metals and alloys; metal oxides; and ceramic compositions having a small nanosize, i.e. about 1-6 nm. The method comprises a synthesis in the solutions of complex liquids from suitable precursors, which precursors are selected from suitable surfactants and alkoxides, by a suitable chemical reaction under mild conditions; and preparing from said materials fine colloids dispersed in various polymer solutions. The water in the solution is preferably non freezing water, the mild conditions are atmospheric pressure and a temperature range of room temperature to 70° C., and the reaction condition is selected among a hydrolysis, reduction and exchange process.
    Type: Grant
    Filed: September 11, 2000
    Date of Patent: March 16, 2004
    Assignee: Yissum Research Development Company of the Hebrew University of Jerusalem
    Inventors: Nissim Garti, Yana Berkovich
  • Patent number: 6695986
    Abstract: An electrically conductive composite is provided having a mesoporous architecture that improves the accessibility of a nanoscopic catalyst, supported on conductive carbon, to a mass-transported reactant, or substrate, thereby leading to enhanced catalytic activity. In particular, the composite is useful for a new class of fuel-cell electrode architectures based on a composite aerogel that improves the accessibility of a carbon-supported Pt electrocatalyst to methanol (MeOH), leading to higher MeOH oxidation activities than observed at the native carbon supported Pt electrocatalyst. The composite comprises a nanoscopic Pt electrocatalyst, a carbon black electron-conducting support, and a silica aerogel.
    Type: Grant
    Filed: September 25, 2002
    Date of Patent: February 24, 2004
    Assignee: The United States of America as represented by the Secretary of the Navy
    Inventors: Debra R. Rolison, Michele L. Anderson, Rhonda M. Stroud
  • Patent number: 6683130
    Abstract: A dispersion comprises at least 30 per cent by weight of particles of a metal oxide having an average primary particle size of less than 200 nm dispersed in a siloxane fluid dispersing medium and a dispersing agent wherein said metal oxide particles are hydrophoobic, and the dispersing agent is polylkylene oxide/polyalkylsiloxane block copolymer comprising at least 30 per cent by weight of the copolymer of polyalkylsiloxane. The dispersion is particularly suitable for use as an ingredient in sunscreening cosmetics.
    Type: Grant
    Filed: November 20, 2001
    Date of Patent: January 27, 2004
    Assignee: Imperial Chemical Industries PLC
    Inventor: Lorna Margaret Kessell
  • Patent number: 6660277
    Abstract: A cosmetic composition comprising a lipophilic clay gel and a hydrophilic clay gel. The two gels are combined or formed in situ to create a gel matrix. This matrix functions like an emulsion to deliver water and oil to the skin or other surface, but can be substantially free of surfactants, emulsifiers and waxes. A method for the preparation of a clay gel matrix is also revealed.
    Type: Grant
    Filed: June 19, 1998
    Date of Patent: December 9, 2003
    Assignee: Avon Products, Inc.
    Inventor: Leona Giat Fleissman
  • Patent number: 6638982
    Abstract: The invention provides a method of preparing a dispersion of a fumed metal oxide in a liquid carrier comprising the following sequential steps: (a) providing a liquid carrier at a pH that effects dissolution of the metal oxide at a rate the same as or greater than the metal oxide dissolution rate in water at a pH of about 8, (b) mixing with the liquid carrier, in any order, one or more aliquots of both a fumed metal oxide and a metal ion source to form a dispersion, such that the dispersion does not coagulate, and (c) optionally adjusting the pH of the dispersion to the pH of the liquid carrier in step (a). The method allows for the preparation of the dispersion to be done with a high solids loading and at a high pH. Furthermore, the dispersion can have a shelf-life of at least about 1 hour or more at 25° C.
    Type: Grant
    Filed: November 14, 2001
    Date of Patent: October 28, 2003
    Assignee: Cabot Corporation
    Inventor: Steven E. Brown
  • Publication number: 20030149116
    Abstract: A dispersant slurry for making spandex, based on phosphated block poly(alkylsiloxane)-poly(alkyleneether) alcohol or aromatic- or alkylaromatic-terminated phosphated poly(alkyleneether) alcohol dispersants, is provided.
    Type: Application
    Filed: January 6, 2003
    Publication date: August 7, 2003
    Inventors: Thomas Edward Carney, Oliver Gutsche, Kai-Volker Schubert
  • Patent number: 6545059
    Abstract: Method for the treatment of mineral fillers using organic phosphate treatment agents. Treated mineral fillers obtained by said method and suspension of these treated mineral fillers in polyols. Use of these suspensions in the manufacture of flexible, semirigid, or rigid polyurethane foams used for the manufacture of molded or nonmolded objects.
    Type: Grant
    Filed: June 22, 1999
    Date of Patent: April 8, 2003
    Assignee: Omya S.A.
    Inventors: Jean-Pierre Fichou, Maurice Husson, Georges Ravet, Pierre Blanchard
  • Patent number: 6531514
    Abstract: A dispersant slurry for making spandex, based on phosphated block poly(alkylsiloxane)-poly(alkyleneether) alcohol or aromatic- or alkylaromatic-terminated phosphated poly(alkyleneether) alcohol dispersants, is provided.
    Type: Grant
    Filed: March 7, 2001
    Date of Patent: March 11, 2003
    Assignee: E.I. du Pont de Nemours and Company
    Inventors: Thomas Edward Carney, Oliver Gutsche, Kai-Volker Schubert
  • Patent number: 6437007
    Abstract: This invention pertains generally to precursors and deposition methods suited to aerogel thin film fabrication. An aerogel precursor sol which contains an oligomerized metal alkoxide (such as TEOS), a high vapor pressure solvent (such as ethanol) and a low vapor pressure solvent (such as water and 1-butanol) is disclosed. By a method according to the present invention, such a precursor sol is applied as a thin film to a semiconductor wafer, and the high vapor pressure solvent is allowed to evaporate while evaporation of the low vapor pressure solvent is limited, preferably by controlling the atmosphere adjacent to the wafer. The reduced sol is then allowed to gel at a concentration determined by the ratio of metal alkoxide to low vapor pressure solvent. One advantage of the present invention is that it provides a stable, spinnable sol for setting film thickness and providing good planarity and gap fill for patterned wafers.
    Type: Grant
    Filed: April 14, 2000
    Date of Patent: August 20, 2002
    Assignee: Texas Instruments Incorporated
    Inventors: Douglas M. Smith, Gregory P. Johnston, William C. Ackerman, Shin-Puu Jeng, Bruce E. Gnade
  • Patent number: 6426371
    Abstract: The invention provides a fast-cured sol material, which is produced by hydrolysis and condensation of the following starting materials: 2-60 parts by weight of a silicon alkoxide; 20-98 parts by weight of an alcohol; 0.5-50 parts by weight of an aqueous media; 0.0001-10 parts by weight of a base; 0.001-30 parts by weight of at least one additive; and optionally 0.0001-10 parts by weight of an acid. A coating of the sol material according to the invention can be directly cured (without aging) to obtain a microporous dielectric film without shrinkage or cracks.
    Type: Grant
    Filed: July 1, 1999
    Date of Patent: July 30, 2002
    Assignees: Industrial Technology Research Institute, Chinese Petroleum Corporation, Taiwan Fertilizer Co., Ltd.
    Inventors: Lih-Ping Li, Li-Mei Chen, Chao-Jen Wang, Hsin-Hsen Lu
  • Patent number: 6423130
    Abstract: The invention relates to phosphoric esters of the general formula I where X is 1 or 2; n is from 2 to 18; m and o are each from 2 to 100; k is from 2 to 4; R″ is H or a linear or branched alkyl radical; and R′ is an alkyl, alkaryl, alkenyl, or sulfopropyl radical, and to there use as dispersants for pigments and fillers in aqueous or organic media.
    Type: Grant
    Filed: April 10, 2001
    Date of Patent: July 23, 2002
    Assignee: Th. Goldschmidt AG
    Inventors: Tammo Boinowitz, Eberhard Esselborn, Arno Knebelkamp, Christian Psiorz, Stefan Silber, Stefan Stadtmüller, Ellen Wallhorn
  • Patent number: 6399544
    Abstract: Pumpable and flowable bentonite clay slurries having a bentonite solids content of about 50% or greater have been prepared for the first time through the use of a non-aqueous fluidizing agent, characterized by being a highly-saturated hydrocarbon oil with low affinity for reactivity with bentonite or other hydrophilic swelling agents such as starches, guars and xanthans. The slurries are useful in the economical transport of bentonite without impairing its swellability in aqueous media in applications such as mining, papermaking and oil drilling.
    Type: Grant
    Filed: March 15, 2000
    Date of Patent: June 4, 2002
    Inventors: Peter H. Fairchild, Ian R. Fairchild
  • Patent number: 6376559
    Abstract: A process for preparing a dispersing component of an inorganic oxide sol which involves dehydrating an aqueous inorganic oxide sol by adding an azeotropic solvent to the aqueous inorganic sol to form an azeotropic mixture, carrying out azeotropic distillation and then surface-treating the dispersing component of the inorganic oxide sol with a silane coupling agent.
    Type: Grant
    Filed: July 27, 1999
    Date of Patent: April 23, 2002
    Assignee: BASF NOF Coatings Co., Ltd.
    Inventors: Keiji Komoto, Keishi Yoshikai, Masahiko Hirono, Yoshifumi Ohama
  • Publication number: 20020043469
    Abstract: Carbon-containing components of cells for the production of aluminium by the electrolysis of alumina dissolved in a cryolite-based molten electrolyte are protected from attack by liquid and/or gaseous components of the electrolyte in the form of elements, ions or compounds, by a refractory boride coating applied from a slurry composed of pre-formed particulate refractory boride in a colloidal carrier which is dried and heated to consolidate the coating.
    Type: Application
    Filed: July 25, 2001
    Publication date: April 18, 2002
    Inventors: Vittorio de Nora, Jainagesh A. Sekhar
  • Patent number: 6372832
    Abstract: A glycol dispersion of an inorganic powder is provided, which comprises glycol and an inorganic powder dispersed therein, said inorganic powder being surface-treated with a dispersant having a solubility of not less than 5 (g/100 g-water) in water of 20° C., and which contains water and/or methanol in the specific amounts. According to the present invention, it is not required to transport a slurry of water, methanol or glycol, but possible to transport in the form of powder, so that efficiency in transportation is not only enhanced, but a drastic simplification in the production steps and a cost reduction are attainable because neither a distillation apparatus for replacing a solvent such as water and methanol with glycol nor a step of wet-pulverizing is required. Moreover, a glycol dispersion of the present invention is able to reproduce the excellent shape and size of the inorganic particles before drying or in the initial state and therefore has an excellent dispersibility.
    Type: Grant
    Filed: January 13, 2000
    Date of Patent: April 16, 2002
    Assignee: Maruo Calcium Company Limited
    Inventors: Naofumi Saito, Seiya Shimizu, Kazunori Ohide, Shiro Minayoshi
  • Patent number: 6328894
    Abstract: A process to purify and classify a dispersion containing stabilized particles having counterions and ions as well as free species is disclosed. The solution may comprise an aqueous media, a solvent media, or a combination of both and can include more than one type of aqueous and/or solvent solutions. The process includes at least the steps, in any order, of substantially removing the particles having sizes above about 1 micron, preferably above 0.5 micron; substantially removing the free species; and exchanging at least a portion of the counterions that are a part of the stabilized particles. The process disclosed is especially useful in purifying dispersions where the ionic stabilized colloidal particles are carbon black having attached organic groups comprising at least one ionic group, or at least one ionizable group, or mixtures thereof.
    Type: Grant
    Filed: January 29, 1999
    Date of Patent: December 11, 2001
    Assignee: Cabot Corporation
    Inventors: Michael K. Chan, Joseph E. Johnson, John Mathew, Friedrich K. von Gottberg
  • Patent number: 6310123
    Abstract: The invention relates to phosphoric esters of the general formula (I): wherein x is 1 or 2; n is a number from 2 to 18; m and n are each a number from 2 to 100; k is a number from 2 to 4; R″ is H or a linear or branched alkyl radical which may be substituted by a functional radical; and R′ is an alkyl, alkaryl, alkenyl or a sulfopropyl radical. The invention further relates to the use of the phosphoric esters as dispersants for pigments and fillers in aqueous or organic media and in particular to methods of forming a highly filled sheet molding compound or bulk molding compound comprising the step of dispersing components of the molding compound with said phosphoric esters.
    Type: Grant
    Filed: February 17, 1999
    Date of Patent: October 30, 2001
    Assignee: Goldschmidt AG
    Inventors: Tammo Boinowitz, Eberhard Esselborn, Arno Knebelkamp, Christian Psiorz, Stefan Silber, Stefan Stadtmüller, Ellen Wallhorn
  • Patent number: 6303663
    Abstract: Silica is rendered hydrophobic by a catalyst-free, in-situ process that includes contact with a hydrophobing agent under vacuum at elevated temperature for a time sufficient to replace adsorbed water in the silica with the hydrophobing agent. The resulting dispersion of hydrophobic silica in an inert, liquid, hydrophobic carrier medium is then subjected to high shear forces for a time sufficient to produce a homogeneous dispersion of hydrophobic silica particles in a defoaming composition.
    Type: Grant
    Filed: March 26, 1999
    Date of Patent: October 16, 2001
    Assignee: Cognis Corporation
    Inventors: Ronald W. Broadbent, Dharmesh Chovatia
  • Patent number: 6297202
    Abstract: The present invention provides improved defoaming compositions and methods. The compositions of the invention are basically comprised of polypropylene glycol, particulate hydrophobic silica and a liquid diluent.
    Type: Grant
    Filed: January 4, 1999
    Date of Patent: October 2, 2001
    Assignee: Halliburton Energy Services, Inc.
    Inventors: Jiten Chatterji, Roger S. Cromwell, Bobby J. King
  • Patent number: 6291535
    Abstract: A sol comprising silica-magnesium fluoride hydrate composite colloidal particles used in an anti-reflection coating material for forming an anti-reflection coating and a process for its preparation are provided. A sol comprising silica-magnesium fluoride hydrate composite colloidal particles having a ratio of silica to magnesium fluoride hydrate MgF2.nH2O, n being in the range between 0.25 and 0.5, in terms of a SiO2/MgF2 weight ratio of from 0.01 to 5 and a primary particle size of 5 to 50 nm. A process for the preparation of an aqueous sol comprising silica-magnesium fluoride hydrate composite colloidal particles which comprises the steps of adding an aqueous fluoride solution to a mixture liquid of a silica sol and an aqueous magnesium salt solution to produce a slurry of an agglomerate comprising silica-magnesium fluoride hydrate composite colloidal particles and removing the salts formed as by-products.
    Type: Grant
    Filed: December 7, 1999
    Date of Patent: September 18, 2001
    Assignee: Nissan Chemical Industries, Ltd.
    Inventors: Yoshitane Watanabe, Keitaro Suzuki, Osamu Tanegashima, Yoshinari Koyama
  • Patent number: 6251958
    Abstract: A process for preparing a defoamer composition by providing a high-shear, in-line mixer having a rotor-stator assembly with at least one concentric set of shearing teeth which rotate at a tip speed of up to about 25 meters per second and feeding to said mixer a melt of a hydrophobic defoaming agent along with a functional carrier liquid at a controlled mass flow rate and temperature. After mixing, the mixture is cooled and discharged into a receiving vessel.
    Type: Grant
    Filed: April 8, 1999
    Date of Patent: June 26, 2001
    Assignee: Henkel Corporation
    Inventors: Puvin Pichai, Kenneth Breindel
  • Patent number: 6221921
    Abstract: A dispersant system for formulating stable non-aqueous siliceous particulate slurries, comprising a vehicle comprising a liquid ester, and a dispersant comprising an alkoxylated aminoalcohol and organophosphate ester. Siliceous particulate slurries in accordance with the present invention can include slurries containing siliceous ceramic particulate (i.e., silicon nitride, silicon carbide, silica, and silicon metal powders partially oxidized by air exposure). A wide variety of linear and cyclic organic esters can be used as a vehicle component, including lactones. The alkoxylated aininoalcohol is typically an ethoxylated aminoethanol oligomer. A wide variety of aromatic and nonaromatic organophosphate ester compounds can be used for the second dispersant component.
    Type: Grant
    Filed: October 14, 1999
    Date of Patent: April 24, 2001
    Assignee: Advanced Ceramics Research, Inc.
    Inventors: John Lang Lombardi, Kevin Haines Johnston, David Zackery Dent
  • Patent number: 6159390
    Abstract: Method for the treatment of mineral fillers using organic phosphate treatment agents. Treated mineral fillers obtained by said method and suspension of these treated mineral fillers in polyols. Use of these suspensions in the manufacture of flexible, semirigid, or rigid polyurethane foams used for the manufacture of molded or nonmolded objects.
    Type: Grant
    Filed: January 31, 1996
    Date of Patent: December 12, 2000
    Assignee: Omya S.A.
    Inventors: Jean-Pierre Fichou, Maurice Husson, Georges Ravet, Pierre Blanchard
  • Patent number: 6130256
    Abstract: An organophilic clay thickener for natural oil systems comprising the reaction product of a smectite-type clay and an organic cation in an amount of from about 75% to about 150% of the cation exchange capacity of the smectite-type clay. Said organophilic clay comprising at least one naturally occurring, resulting in increased efficiency as a thickener in natural oil systems.
    Type: Grant
    Filed: May 7, 1993
    Date of Patent: October 10, 2000
    Assignee: Rheox, Inc.
    Inventor: Hemi Nae
  • Patent number: 6110439
    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.
    Type: Grant
    Filed: March 3, 1998
    Date of Patent: August 29, 2000
    Assignee: Armstrong World Industries, Inc.
    Inventors: Ravindra Deshpande, Lisa A. Stover
  • Patent number: 6107351
    Abstract: The present invention is neutral-aged hydrophobic silica gels having a reduced surface area and a method for their preparation. The method comprises three steps, where in the first step a mixture comprising a silica hydrosol and colloidal silica is contacted with a strong mineral acid at a pH less than about 1 to form a silica hydrogel having incorporated therein colloidal silica. In the second step the silica hydrogel is aged at a pH within a range of about pH 3.5 to pH 8. In the third step the silica hydrogel is contacted with an organosilicon compound in the presence of a catalytic amount of a strong acid to effect hydrophobing of the silica hydrogel to form a hydrophobic silica hydrogel having a surface area within a range of about 100 m.sup.2 /g to 450 m.sup.2 /g in the dry state. In a preferred method the hydrophobic silica hydrogel and is further contacted with a sufficient quantity of a water-immiscible organic solvent to convert the hydrophobic silica hydrogel into a hydrophobic silica organogel.
    Type: Grant
    Filed: February 23, 1998
    Date of Patent: August 22, 2000
    Assignee: Dow Corning Corporation
    Inventors: Gary Thomas Burns, Qin Deng, James Richard Hahn, Clifford Carlton Reese
  • Patent number: 6090857
    Abstract: This invention relates to a foam control agent which comprises the reaction product prepared by reacting: (a) a hydrocarbon carrier; (b) a precipitated amorphous silicate; (c) a refractory clay; and (d) a reactive silicone in the presence of a catalytically effective amount of a basic catalyst at elevated temperatures.
    Type: Grant
    Filed: September 29, 1998
    Date of Patent: July 18, 2000
    Assignee: Ashland Inc.
    Inventors: Jeffrey Todd Tamburrino, Andrew Anthony Romano
  • Patent number: 6017968
    Abstract: A thickened, shear thinnable composition comprising a water-miscible organic liquid, alumina, water and an effective amount of a gelling agent that will flocculate or gel the alumina to the desired degree but permit the gelled composition to be rendered less viscous or pourable upon the application of a shear force.
    Type: Grant
    Filed: February 15, 1995
    Date of Patent: January 25, 2000
    Assignee: CONDEA Vista Company
    Inventors: Ronald L. Beggs, J. Scott Leigh, Jeff T. Fenton
  • Patent number: 5997894
    Abstract: A flexible coating composition of hard ceramic particles, a binder and a polymer, and a method of making the same is disclosed. The coating composition can withstand an animal attack with pressures.gtoreq.22,000 psi.
    Type: Grant
    Filed: September 19, 1997
    Date of Patent: December 7, 1999
    Assignee: Burlington Bio-Medical & Scientific Corp.
    Inventors: Melvin Blum, Michael Roitberg
  • Patent number: 5902226
    Abstract: A propanol sol of silica having a specific surface area of 25 to 550 m.sup.2 /g, the sol having an SiO.sub.2 concentration of 10 to 50% by weight of SiO.sub.2 and a residual content of a medium containing 7.5% by weight or less of water based on the SiO.sub.2 content and 90% by weight or more of propanol, is prepared by an improved process involving replacing the aqueous medium in an acidic aqueous sol of silica containing 5 to 50% by weight of SiO.sub.2 and a medium having a water content of 15% by weight or more with propanol by an atmospheric distillation method in which a concentration of 5 to 50% by weight of SiO.sub.2 in the sol and 1 to 85% by weight of methanol in the medium in the sol is maintained when the medium in the sol during the replacement contains 15 to 0.5% by weight of water.
    Type: Grant
    Filed: March 15, 1996
    Date of Patent: May 11, 1999
    Assignee: Nissan Chemical Industries, Ltd.
    Inventors: Keiko Tasaki, Yasuyoshi Hamada, Takafumi Yokoyama