By Precipitating Patents (Class 423/339)
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Patent number: 5395604Abstract: A powder evacuated thermal insulating panel using generally spherical and porous silica particles of a median size less than about 100 nanometers in diameter, a pour packing density of about 0.4 to 0.6 g/cm.sup.3 and an external surface area in the range of about 90 to 600 m.sup.2/ g is described. The silica powders are prepared by reacting a tetraakyl silicate with ammonia and water in an alcohol solvent, distilling the solution after the reaction to remove the ammonia and recover the alcohol. The resulting aqueous slurry was dried, ball-milled, and dried again to provide the silica particles with defined internal and external porosity. The nanometer size and the large external surface area of the silica particles along with the internal and external porosity of the silica particles provide powder evacuated thermal insulating panels with significantly higher R-values than obtainable using previously known silica powders.Type: GrantFiled: May 3, 1994Date of Patent: March 7, 1995Assignee: Martin Marietta Energy Systems, Inc.Inventors: Michael T. Harris, Osman A. Basaran, Thomas G. Kollie, Fred J. Weaver
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Patent number: 5395605Abstract: Novel precipitated silica particulates having low water uptake and high BET and CTAB surfaces, well adapted as reinforcing fillers for, e.g., the silicones, are conveniently prepared by heat treating certain starting material precipitated silica particulates at a temperature of at least 700.degree. C., for at least one minute.Type: GrantFiled: May 3, 1991Date of Patent: March 7, 1995Assignee: Rhone-Poulenc ChimieInventors: Jacques Billion, Yvonick Chevallier, Jean-Claude Morawski
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Patent number: 5376347Abstract: A method of producing uniform inorganic microspheres with a particle size of 0.01 to 500 .mu.m by injecting an aqueous solution containing a particle-forming material into an organic solvent. The method includes injecting the aqueous solution into the organic solvent through a macromolecular membrane having a hydrophobic surface and having pores substantially uniform in pore size and extending in the direction of thickness of the membrane, substantially straight through the membrane, so that a path length of each of the pores corresponds substantially to a thickness of the membrane, to form, in said organic solvent, a large number of emulsion particles substantially uniform in size and then producing uniform inorganic microspheres from said emulsion particles on a one emulsion particle-to-one microsphere basis. The pores in the membrane are formed by either a corpuscular or laser beam.Type: GrantFiled: July 15, 1992Date of Patent: December 27, 1994Assignees: Osaka Gas Company, Limited, Liquid Gas Co., Ltd., Suzuki Yushi Industrial Co., Ltd.Inventors: Masamichi Ipponmatsu, Masashi Nishigaki, Akira Hirano, Tsuyoshi Tsurutani
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Patent number: 5366645Abstract: A modified amorphous silica is described which, apart from optionally present usual additives, comprises 40 to 85 wt-% silica and 60 to 15 wt-% paraffin, silicone or vegetable oil and/or ethylene glycol. The modified amorphous silica is prepared by bringing together, apart from optionally present usual additives, silica with such a quantity of paraffin, silicone or vegetable oil and/or ethylene glycol that the finished, modified silica has a paraffin, silicone or vegetable oil and/or ethylene glycol content of 60 to 15 wt-%. The modified amorphous silica is suitable as an anti-blocking agent, which can be advantageously prepared as concentrate (masterbatch). Surprisingly, upon preparing such a concentrate the melt-flow index hardly falls compared with the melt-flow index of the polyolefin which forms the basis of the concentrate. Thus it is possible to incorporate large quantities of the modified silica into the concentrate in very homogeneous distribution.Type: GrantFiled: May 15, 1992Date of Patent: November 22, 1994Assignee: W. R. Grace & Co.-Conn.Inventor: Richard Sobottka
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Patent number: 5354548Abstract: This invention provides a three dimensional inorganic oxide structure comprising a myriad of cavities interconnected by holes having a narrow pore size distribution, in which the diameters of the cavities is in the range from 1 to 50 .mu.m and that of the holes in the range 1 to 10 .mu.m and in which the pore volume in the range 1 to 10 .mu.m is at least 2 cc/g and in which the inorganic oxide is selected from alumina, silica, titania, zirconia and mixtures thereof and a process for the preparation of such structures.Type: GrantFiled: November 2, 1992Date of Patent: October 11, 1994Assignee: Unilever Patent Holdings B.V.Inventors: Abraham Araya, Anthony L. Lovell
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Patent number: 5346678Abstract: A process for preparation of silicon-32 is provide and includes contacting an irradiated potassium chloride target, including spallation products from a prior irradiation, with sufficient water, hydrochloric acid or potassium hydroxide to form a solution, filtering the solution, adjusting pH of the solution to from about 5.5 to about 7.5, admixing sufficient molybdate-reagent to the solution to adjust the pH of the solution to about 1.Type: GrantFiled: September 25, 1992Date of Patent: September 13, 1994Assignee: The United States of America as represented by the United States Department of EnergyInventors: Dennis R. Phillips, Mark A. Brzezinski
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Patent number: 5342598Abstract: Precipitated silica particulates having a BET specific surface ranging from 20 to 300 m.sup.2 /g, a CTAB specific surface ranging from 10 to 200 m.sup.2 /g, an oil uptake (DBP) ranging from 80 to 400 cm.sup.3 /100 g, a pore volume ranging from 1 to 10 cm.sup.3 /g and a mean pore diameter ranging from 10 to 50 nm, well adapted for such applications as the coating of paper and catalysis, are prepared by (a) simultaneously introducing a silicate and an acid into a dispersion of colloidal silica, thereby providing a silica suspension, (b) next decreasing the pH of such suspension to a value ranging from 3 to 7, and (c) then separating the silica particulates from the final suspension and drying them.Type: GrantFiled: January 24, 1992Date of Patent: August 30, 1994Assignee: Rhone-Poulenc ChimieInventor: Jacques Persello
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Patent number: 5342876Abstract: A porous and spherical silica is recovered in high yields from a neutralized product of an alkali silicate obtained by using an acrylamide type polymer as a coagulation growing agent, and the above silica is reacted as a precursor with a metal compound of the Group II of periodic table in an aqueous medium to obtain amorphous or fine, laminar and crystalline porous and spherical silica or silicate granules having a high degree of true sphericality, a symmetrical grain size distribution and a refractive index over a range of from 1.4 to 1.7. The porous and spherical granules have a primary grain diameter of 0.3 to 30 .mu.m as observed through an electron microscope, have an apparent specific gravity of from 0.05 to 0.5 g/ml, and are cheaply obtained in high yields, and can hence be used as a filler for various paints and resins.Type: GrantFiled: January 25, 1993Date of Patent: August 30, 1994Assignee: Misuzawa Industrial Chemicals, Ltd.Inventors: Kiyoshi Abe, Kazuhiko Suzuki, Hiroshi Ogawa, Masaichi Kikuchi
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Patent number: 5321070Abstract: The invention relates to mixtures including resorcinol and silica which are used as adhesion promoters for improving the adhesion between textile or metal strength carriers and rubber or plastics. The mixtures in accordance with the invention exhibit a sharply limited sublimation behavior with regard to the resorcin.Type: GrantFiled: January 22, 1993Date of Patent: June 14, 1994Assignee: Degussa AktiengesellschaftInventors: Karl Meier, Udo Goerl, Siegfried Wolff
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Patent number: 5318833Abstract: A polyester film having uniform surface and excellent running property and transparency is disclosed. Said polyester film is characterized by containing 0.01-5 wt. % of porous precipitated silica particles which are coagulates of primary particles having an average particle diameter of 0.01-0.1 .mu.m and have a pore volume of 0.05-0.5 ml/g, a specific surface area of 30-150 m.sup.2 /g and an average particle diameter of 0.1-0.5 .mu.m.Type: GrantFiled: March 25, 1992Date of Patent: June 7, 1994Assignee: Diafoil Hoechst Company, LimitedInventors: Masahiko Fujimoto, Kazuo Endo
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Patent number: 5266289Abstract: A process for producing a high-purity silica, which comprises the steps of reacting a crude silica with ammonium fluoride, acid ammonium fluoride or a mixture thereof in an aqueous medium to produce ammonium silicofluoride, separating the ammonium silicofluoride from an unreacted silica and impurities by the means of a solid/liquid separation, and reacting the thus-obtained ammonium silicofluoride with ammonia in an aqueous medium. This process is a low cost process, and enables to control properties of silica.Type: GrantFiled: November 14, 1990Date of Patent: November 30, 1993Assignee: Nissan Chemical Industries Ltd.Inventors: Makoto Tsugeno, Kenji Tanimoto, Masao Kubo
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Patent number: 5256386Abstract: Silica particles which are substantially spherical, have a particle size of 1 to 100 .mu.m, a very narrow pore size distribution and a low alkali metal content. The particles can be prepared by sol-gel technique using emulsification technique for drop formation. The process comprises a sol growth step in a basic environment based on ammonium or amines and a post-treatment in such an environment. The silica particles are particularly suitable for use in chromatography as they have very good particle and porosity properties and high purity.Type: GrantFiled: June 14, 1990Date of Patent: October 26, 1993Assignee: Eka Nobel ABInventors: Mats Nystrom, Wolgang Herrmann, Bernt Larsson
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Patent number: 5254337Abstract: Animal's coats are deodorized and optionally treated in other manners by the application thereto of a composition comprising a crystalline siliceous molecular sieve which has been at least partially activated with respect to organic molecular species and in which at least about 90 percent of the framework tetrahedral oxide units are SiO.sub.2 tetrahedra and which have a sorptive capacity for water at 25.degree. C. and 4.6 torr of less than 10 weight percent.Type: GrantFiled: May 2, 1988Date of Patent: October 19, 1993Assignee: UOPInventors: Bonita K. Marcus, Anthony J. Gioffre
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Patent number: 5236623Abstract: Silica colloids having a spherical form, a mean diameter of between about 10 and 100 nm and a polydispersity index between about 1 and 4. A process for making silica colloids is also provided comprising a) forming a reaction medium by simultaneously adding an acidifying agent and an alkaline silicate solution to a reaction vessel, b) reacting the acidifying agent and alkaline silicate solution, and c) maintaining a constant volume of the reaction medium by drawing off the reaction medium.Type: GrantFiled: December 12, 1990Date of Patent: August 17, 1993Assignee: Rhone-Poulenc ChimieInventor: Yvonick Chevallier
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Patent number: 5234673Abstract: Precipitated silica gels having high surface areas and low oil absorption values are produced by a low temperature synthesis precipitation process. The precipitated silicas have unique flatting characteristics and are additionally useful as conditioning agents for food and salt and in dentifrice formulations.Type: GrantFiled: April 24, 1991Date of Patent: August 10, 1993Assignee: J. M. Huber CorporationInventors: Patrick D. McGill, William C. Fultz
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Patent number: 5230953Abstract: Silica particles having an average particle size of 5 to 100 .mu.m, a BET specific surface area of not more than 20 m.sup.2 /g and a pore volume of not more than 0.1 ml/g, each of which has on its surface a plurality of protuberances with a smooth configuration , a diameter at half the protuberance height of the said protuberance being 0.2 to 5.0 .mu.m and a height of the said protuberance being 0.2 to 4.0 .mu.m, and a process for producing the silica particles, which comprises (A) reacting hydrosilicofluoric acid, ammonium silicofluoride or a mixture thereof with ammonia in an aqueous medium to form a silica slurry, (B) separating a silica from the silica slurry, and (C) calcining, after optionally drying, the separated silica at a temperature of not less than 500.degree. C.Type: GrantFiled: December 11, 1990Date of Patent: July 27, 1993Assignee: Nissan Chemical Industries Ltd.Inventors: Makoto Tsugeno, Yasushi Takako, Masao Kubo, Tokumi Mochiyama, Yoshito Yuri
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Patent number: 5231066Abstract: A bimodal silica gel particle, its method of preparation and its use as a catalyst support in the polymerization of olefins is disclosed. The bimodal silica gel particle exhibits a bimodal pore radius distribution, wherein the silica gel particle has a first average pore radius and a second average pore radius differing by at least about 20 .ANG.. The bimodal silica gel particle is useful as a support for a transition metal-based catalyst to provide a polyolefin having a broad or bimodal molecular weight distribution.Type: GrantFiled: September 11, 1991Date of Patent: July 27, 1993Assignee: Quantum Chemical CorporationInventors: Louis J. Rekers, Roger D. Laib
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Patent number: 5225177Abstract: Novel precipitated silicon dioxide abrasive compositions which can be incorporated into therapeutic toothpaste compositions containing soluble fluoride salts are disclosed. The abrasives comprise low structure, high fluoride compatible amorphous precipitated silicon dioxides (silicas) having a controlled refractive index for use in low water clear gel dentifrice applications. Also provided are methods for preparation of the novel silicon dioxide abrasives and resulting toothpaste formulations containing such abrasives.Type: GrantFiled: January 19, 1990Date of Patent: July 6, 1993Assignee: J. M. Huber CorporationInventors: Satish K. Wason, William C. Fultz
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Patent number: 5206189Abstract: An improved method for the production of a monolithic multicomponent oxide glass is achieved by forming an oxide host gel by a sol-gel process, placing the host gel in an aqueous solution of a salt of at least one metal selected from the group consisting of Li, Na, K, Rb, Cs, Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Pb, precipitating the metal salt in the gel and sintering the gel containing the precipitated salt. The method can incorporate large amounts of metals into the glass which are otherwise difficult or impossible to incorporate into precursor gels by conventional methods.Type: GrantFiled: October 25, 1991Date of Patent: April 27, 1993Assignees: Instituto Guido Donegani S.p.A., Enichem S.p.A.Inventor: J. Brian Caldwell
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Patent number: 5200165Abstract: A method of obtaining precipitated amorphous silicas with substantially a tertiary aggregate structure (whether as an aqueous slurry, as cake, gel or otherwise) useful for coating and/or incorporation in paper and other substrates (e.g. rubber, plastics and the like) from a geothermal fluid (naturally or artificially generated--natural, including water infusion into geothermal systems) having sufficient silicic acid concentration, said method comprising:A. ageing the fluid to effect polymerization, thus establishing a silica sol, ageing meaning a process in which the source fluid after being made supersaturated with respect to amorphous silica is held for a period of time,B. optionally (prior to, with and/or after step A--preferably prior to in order to reduce arsenic adsorption) reducing the temperature of the geothermal fluid and/or sol as the case may be,C. inducing precipitation of amorphous silica from the sol under conditions that will provide the tertiary aggregate structure, andD.Type: GrantFiled: March 20, 1990Date of Patent: April 6, 1993Assignees: Tasman Pulp & Paper Co. Limited, Geochemistry Research LimitedInventors: Ross T. Harper, James H. Johnston, Nicholas Wiseman
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Patent number: 5196267Abstract: Silica microspheres formed by hydrolysis of a silica precursor having a mean diameter in the range of about 0.1 to 10 .mu.m are provided with a thin surface layer, often a monolayer, of a metal to provide the appearance of a solid particle of the metal as its oxide. The microspheres are contacted with an aqueous or alcoholic solution of a metal compound to deposit the surface layer.Type: GrantFiled: June 21, 1991Date of Patent: March 23, 1993Assignee: Allied-Signal Inc.Inventors: Timothy J. Barder, Philip D. DuBois
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Patent number: 5165907Abstract: A method for producing high purity silica and ammonium fluoride from silicon tetrafluoride-containing gas wherein silicon tetrafluoride-containing gas from the acidulation of phosphorus-containing rock is recovered and the liquid entrainment is separated from the gas. The recovered gas is converted to an ammonium fluosilicate solution and is ammoniated to produce high purity silica and ammonium fluoride. The recovered gas can be converted to an ammonium fluosilicate solution either by absorbing the gas directly in a solution of ammonium fluoride or by first absorbing the gas in water to produce fluosilicic acid and then reacting the fluosilicic acid with ammonia or ammonium fluoride.Type: GrantFiled: December 31, 1990Date of Patent: November 24, 1992Assignee: IMCERA Group Inc.Inventor: Paul C. Chieng
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Patent number: 5123964Abstract: Finely divided precipitated silica with high structure and a______________________________________ BET surface (DIN 66 132) of 150 to 350 m.sup.2 /g Stamping density (DIN 53 194) between 60 and 120 g/l DBP number between 3.0 and 4.0 ml/g Particle size distribution at least 70% from 1 to 6 .mu.m ______________________________________can be prepared by heating a mixture of water and sodium silicate under agitation to a temperature of 70.degree. to 80.degree. C., adding concentrated sulfuric acid into this mixture until half of the alkali present has been neutralized, shearing the reaction mixture and optionally raising the temperature at the same time to 86.+-.5.degree. C. Concentrated sulfuric acid is added after a period of 30 to 120 minutes at a rather high rate until the pH of the silica suspension produced is 3.0 to 3.Type: GrantFiled: May 16, 1991Date of Patent: June 23, 1992Assignee: Degussa AktiengesellschaftInventors: Dieter Kerner, Adolf Wagner, Felix Schmidt, Dietrich Bauer
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Patent number: 5124143Abstract: The toothpaste for preventative oral hygiene contains a mixture of synthetically prepared precipitated silicic acid and perlite in addition to a solvent as cleaning body.A mixture consisting of glycerol (86%) and water is used as solvent.Type: GrantFiled: December 7, 1988Date of Patent: June 23, 1992Assignee: Degussa AGInventors: Hans R. Muhlemann, Karl-Hans Muller, Matthias Neumuller
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Patent number: 5122360Abstract: The present invention provides a method for preparing metal oxide powder. A first solution, which is substantially organic, is prepared. A second solution, which is an aqueous solution substantially immiscible in the first solution, is prepared and delivered as drops to the first solution. The drops of the second solution are atomized by a pulsed electric field forming micro-drops of the second solution. Reagents in the first solution diffuse into and react with reactants in the micro-drops of the second solution forming metal hydroxide or oxalate particles. The metal hydroxide or metal oxalate particles are then recovered and dried to produce the metal oxide powder. An apparatus for preparing a metal oxide powder is also disclosed.Type: GrantFiled: November 27, 1989Date of Patent: June 16, 1992Assignee: Martin Marietta Energy Systems, Inc.Inventors: Michael T. Harris, Timothy C. Scott, Charles H. Byers
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Patent number: 5112499Abstract: A two-stage process for treating acidic gypsum pond water for reuse or for discharge is disclosed. The first stage blends raw acidic pond water with recycled lime-treated slurry from the second stage of the process. The resulting elevation in pH causes CaF.sub.2 and SiO.sub.2 to precipitate and the precipitated material is discarded onto the gypsum storage area. The supernatant water can be used in the wet grinding mill and/or further treated in a second stage with lime to produce treated water which meets government environment standards for discharge. The slurry of calcium phosphate formed in the second (liming) stage is recycled to the first stage.Type: GrantFiled: May 22, 1991Date of Patent: May 12, 1992Assignee: Freeport-McMoran Resource Partners, Limited PartnershipInventors: Michael A. Murray, Charles W. Weston
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Patent number: 5110574Abstract: Process for the production of cleansing, polishing and thickening silica for use in toothpastes, which is characterized in that using the conventional precipitation processes, silica suspensions are obtained of various particles sizes and particle densities and are mixed thoroughly together until the mixture is homogenous in the suspension phase and the resulting suspension mixture is treated in the conventional manner by filtering, drying and comminuting.Type: GrantFiled: December 7, 1988Date of Patent: May 5, 1992Assignee: Degussa AktiengesellschaftInventors: Helmut Reinhardt, Adam Becker, Robert Kuhlmann, Peter Nauroth
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Patent number: 5110586Abstract: A white colored deodorizer comprising zinc oxide and at least one oxide selected from the group consisting of aluminium oxide and silicon oxide and a method for preparation of it are disclosed.Type: GrantFiled: June 21, 1990Date of Patent: May 5, 1992Assignee: Titan Kogyo Kabushiki KaishaInventors: Tokumitsu Kurihara, Tatsuo Saito, Hidefumi Harada
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Patent number: 5102676Abstract: Amorphous silica can be prepared in a stable and pumpable suspension, suitable for use in alcoholic beverage stabilisation, by adding a polysaccharide or inorganic gelling agent. Examples of polysaccharides are carboxy methyl celluloses, guar gum and Xanthan gum. Preferably the suspension contains sorbic acid, benzoic acid or a benzoate to give synergistic action with the polysaccharide.Type: GrantFiled: December 22, 1989Date of Patent: April 7, 1992Assignee: Unilever Patent Holdings B.V.Inventors: Derek Aldcroft, John R. Newton
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Patent number: 5098695Abstract: A precipitated silica, suitable for use in toothpastes, has a high absorbency, i.e. 110 to 180 cm.sup.3 100 g, and good abrasivity with a plastics abrasion value of 12 to 20. The silica provides abrasion even at a relatively low particle size.Type: GrantFiled: January 24, 1991Date of Patent: March 24, 1992Assignee: Unilever Patent Holdings, B.V.Inventors: John R. Newton, James P. Quinn, Peter W. Stanier
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Patent number: 5094829Abstract: Reinforced precipitated silica having, on a coating-free and impregnant-free basis, a surface area of from about 220 to about 340 square meters per gram, a pore diameter at the maximum of the volume pore size distribution function of from about 9 to about 20 nanometers, and a total intruded volume of from about 2.6 to about 4.4 cubic centimeters per gram, is produced by a process wherein precipitated silica is heavily reinforced using a multiplicity of precipitation and aging steps.Type: GrantFiled: June 21, 1990Date of Patent: March 10, 1992Assignee: PPG Industries, Inc.Inventors: Thomas G. Krivak, Timothy A. Okel, Melvin P. Wagner
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Patent number: 5066420Abstract: Silica colloids having a spherical form, a mean diameter of between about 10 and 100 nm and a polydispersity index between about 1 and 4. A process for making silica colloids is also provided comprising a) forming a reaction medium by simultaneously adding an acidifying agent and an alkaline silicate solution to a reaction vessel, b) reacting the acidifying agent and alkaline silicate solution, and c) maintaining a constant volume of the reaction medium by drawing off the reaction medium.Type: GrantFiled: August 5, 1987Date of Patent: November 19, 1991Assignee: Rhone-Poulenc Specialites ChimiquesInventor: Yvonick Chevallier
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Patent number: 5064473Abstract: Disclosed herein is a filler for heat-sensitive recording paper which comprises amorphous silica obtained by reacting hydrosilicofluoric acid and/or an alkali salt thereof with an alkali (such as ammonia and dimethylamine). The filler has a solid acid strength (pk.sub.a) of +6.8 to 3.3, and oil absorption value of 120 to 200 ml/100 g, a nitrogen adsorption specific surface area of 110 to 350 m.sup.2 /g (by BET method), and a water vapor adsorption specific surface area of 200 to 300 m.sup.2 /g (by BET method).Type: GrantFiled: February 13, 1990Date of Patent: November 12, 1991Assignees: Nissan Chemical Industries, Ltd., Shionogi & Co. Ltd.Inventors: Masao Kubo, Akihiro Shiroishi, Ikuo Uno, Takashi Nishiyama
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Patent number: 5049371Abstract: A novel process is described for the preparation of monodisperse ceramic ders wherein particulate oxides or hydroxides are obtained by reaction of hydrolysable compounds with water. The reaction is carried out in the presence of a complexing agent and, optionally, a stabilizer.Type: GrantFiled: October 28, 1988Date of Patent: September 17, 1991Assignee: Fraunhofer-Gesellschaft zur Forderung der Angewandten Forschung e.V.Inventors: Gunter Rinn, Rudiger Nass
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Patent number: 5034207Abstract: Finely divided precipitated silica for use as a delustering agent with high structure and a______________________________________ BET surface (DIN 66 132) of 150 to 350 m.sup.2 /g Stamping density (DIN 53 194) between 60 and 120 g/l DBP absorption number between 3.0 and 4.0 ml/g Particle size distribution at least 70% from 1 to 6 .mu.m ______________________________________ can be prepared by heating a mixture of water and sodium silicate under agitation to a temperature of 70.degree. to 80.degree. C., adding concentrated sulfuric acid into this mixture until half of the alkali present has been neutralized, shearing the reaction mixture and optionally raising the temperature at the same time to 86.degree..+-.5.degree. C. Concentrated sulfuric acid is added after a period of 30 to 120 minutes at a rather high rate until the pH of the silica suspension produced is 3.0 to 3.5.Type: GrantFiled: June 22, 1990Date of Patent: July 23, 1991Assignee: Degussa AktiengesellschaftInventors: Dieter Kerner, Adolf Wagner, Felix Schmidt, Dietrich Bauer
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Patent number: 5032369Abstract: A method of removing silicon from a waste hydrochloric acid pickling solution is disclosed which comprises stirring the waste solution long enough to form a sludge having a particle size such that the sludge can be separated by a conventional means such as filtration through a filter of at least 0.1 .mu.m in pore diameter, centrifugation or sedimentation. The stirring period can be greatly reduced by adding to the waste pickling solution sludge recovered from an aged waste hydrochloric acid pickling solution or a carbonaceous material such as carbon black having hydrophilic groups on the surface. The sludge is also useful as a filter medium in filtration of the waste pickling solution to remove silicon. The present method can decrease the silicon content to 0.01% or less in terms of converted SiO.sub.2 /Fe.sub.2 O.sub.3 weight ratio.Type: GrantFiled: December 20, 1988Date of Patent: July 16, 1991Assignee: Sumitomo Metal Industries, Ltd.Inventors: Hidenobu Kondo, Tatsuhiko Shigematsu, Masatake Tateno, Yatsuhiro Kawara, Yoshihisa Makino
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Patent number: 5028360Abstract: A method of manufacturing spherical silica particles comprising the steps of processing in an acid-containing solution and then washing with water the coagulant derived from an aqueous alkali metal silicate solution extruded through pores in a water-miscible organic medium or acid solution, wet-grinding the amorphous silica thus obtained in a liquid dispersion medium to obtain a fine particle silica suspension with a weight average particle size of 10 .mu.m or less, spray-drying this fine particle silica suspension with hot air and sintering the spherical granulated silica thus obtained. According to the present invention, the high-purity spherical silica particles can be obtained with high solidity and adjusted surface smoothness without any complicated operation or waste water treatment for use as a sealant filler for highly-integrated IC electronic parts.Type: GrantFiled: April 16, 1990Date of Patent: July 2, 1991Assignee: Nitto Chemical Industries Co., Ltd.Inventors: Yuziro Ito, Takashi Higashiogawa, Masahiro Matsuura, Koichi Orii, Yasumasa Yamaguchi
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Patent number: 5028407Abstract: A method of producing a high purity silica powder which can be fused to form transparent, bubble-free particles. An ammonium fluosilicate solution is purified preliminarily by removing colloidal-sized silica onto which impurities in the solution have been adsorbed. The high purity powder is produced by ammoniation of an unsaturated aqueous solution of ammonium fluosilicate. Silica powder produced is filtered, washed, and dried before fusion. Additional pre-fusion treatments such as washing, hydrothermal leaching, calcination, and a combination thereof, may be utilized to ensure that the concentration of volatile material is low.Type: GrantFiled: January 25, 1990Date of Patent: July 2, 1991Assignee: International Minerals & Chemical Corp.Inventors: Paul C. Chieng, Vikram P. Mehrotra, Chin-Liang Chou
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Patent number: 5023071Abstract: Metal oxide powders, which are chemically uniform and free-flowing, can be formed by dissolving a metal alkoxide in a non-polar organic solvent, adding water to the resulting composition and then emulsifying the blend of water and solvent containing the alkoxide to cause hydrolysis of the alkoxide. The hydrolysis reaction forms the desired metal oxide as a precipitate which can be recovered by a simple filtration process.Type: GrantFiled: April 30, 1990Date of Patent: June 11, 1991Assignee: Akzo America Inc.Inventor: Fawzy G. Sherif
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Patent number: 5011669Abstract: A process for producing a rod-form silica from a silicic acid ester according to a sol-gel process, which silica has a rod-form having a high aspect ratio and is advantageously used as a filler for resin sealants for semiconductors, is provided, which process comprises adding 35 to 150 parts by weight of a sol of a silicic acid ester to 100 parts by weight of a hydrophobic medium to form an emulsion, subjecting the emulsion to a temperature rise at two stages, the first temperature rise being by 5.degree. to 30.degree. C. at a rate of 10.degree. to 200.degree. C./min. or less and the second temperature rise being by 3.degree. to 20.degree. C. at a rate of 0.5.degree. to 10.degree. C./min., to form a rod-form silica.Type: GrantFiled: January 24, 1990Date of Patent: April 30, 1991Assignee: Chisso CorporationInventors: Katsuyoshi Tsuchiya, Kaneo Noake
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Patent number: 5009874Abstract: Hydrophobic, essentially spheroidal precipitated silica particulates, well adapted as a reinforcing filler material for silicone elastomers, have a density of at least 0.15, a water wettability of at least 20% and a maximum water uptake of 5%.Type: GrantFiled: April 13, 1988Date of Patent: April 23, 1991Assignee: Rhone-Poulenc ChimieInventors: Francois Parmentier, Jacques Persello
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Patent number: 4992251Abstract: Amorphous silicas suitable for use as abrasives in transparent toothpastes can be prepared by a precipitation route. These silicas are distinguished by having a BET surface area of 420 to 550 m.sup.2 /g, a weight mean particle size of 5 to 20 micron, a perspex abrasion value of 15 to 28, a mean pore diameter from 3 to 8 nm and a transmission of at least 70% in the R1 range from 1.444 to 1.460.Type: GrantFiled: September 15, 1988Date of Patent: February 12, 1991Assignee: Unilever Patent Holdings B.V.Inventors: Derek Aldcroft, John R. Newton, Peter W. Stanier
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Patent number: 4983369Abstract: A process for producing highly uniform microspheres of silica having an average diameter of 0.1-10 .mu.m from the hydrolysis of a silica precursor, such as tetraalkoxysilanes, which is characterized by employing precursor solutions and feed rates which initially yield a two-phase reaction mixture.Type: GrantFiled: November 22, 1989Date of Patent: January 8, 1991Assignee: Allied-Signal Inc.Inventors: Timothy J. Barder, Philip D. DuBois
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Patent number: 4973462Abstract: This invention concerns a process for producing high purity silica with less than 5 ppm of impurities from cheap alkali silicate aqueous solution (water glass) for industrial use, which commonly contains more than 2000 ppm of impurities, by directly adding water glass to a mineral acid solution, such as hydrochloric acid, nitric acid, and sulfuric acid so as to dissolve impurities in the mineral acid solution and form silica precipitate, and then rinsing the silica precipitate with a mineral acid solution, provided that the viscosity of the water glass is adjusted to 10-10000 poise in advance of adding to the mineral acid solution.Type: GrantFiled: November 9, 1989Date of Patent: November 27, 1990Assignee: Kawatetsu Mining Company, Ltd.Inventors: Seki Akira, Yuuki Narita, Shunroh Nagata
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Patent number: 4956167Abstract: An amorphous silica, especially precipitated silica, suitable for use in toothpastes, has a high abrasivity represented by a perspex abrasion value in the range from about 23 to about 35.Type: GrantFiled: March 22, 1989Date of Patent: September 11, 1990Assignee: Unilever Patent Holdings B.V.Inventors: Derek Aldcroft, John R. Newton, James P. Quinn, Peter W. Stanier
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Patent number: 4943425Abstract: A method of making high purity, dense silica of large particles size is described. Tetraethylorthosilicate is mixed with ethanol and is added to a dilute acid solution having a pH of about 2.25. The resulting solution is digested for about 5 hours, then 2N ammonium hydroxide is added to form a gel at a pH of 8.5. The gel is screened through an 18-20 mesh screen, vacuum baked, calcined in an oxygen atmosphere and finally heated to about 1200.degree. C. in air to form a large particle size, high purity, dense silica.Type: GrantFiled: April 1, 1988Date of Patent: July 24, 1990Assignee: GTE Laboratories IncorporatedInventors: Sophia R. Su, Leo F. Fitzpatrick
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Patent number: 4940571Abstract: A method of making large particle size, high purity, dense silica is described. Tetraethylorthosilicate ethanol solution is added to a 2N ammonium hydroxide solution containing silicic acid having an average particle size of about 15 micrometers to form a precipitate followed by a digestion of the precipitate in the solution. The precipitate is filtered through a screen having 45 micrometer openings and dried to form a dried powder. The dried powder is then calcined in an oxygen atmosphere followed by densifying it by heating at a temperature of about 1200.degree. C. in air to form a large particle size, high purity, dense silica.Type: GrantFiled: April 1, 1988Date of Patent: July 10, 1990Assignee: GTE Laboratories IncorporatedInventors: Sophia R. Su, Leo F. Fitzpatrick, Sheryl A. Robillard
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Patent number: 4915705Abstract: A process for producing high grade silica and fluorine-containing coproducts from fluosilicic acid is described. To produce silica, the fluosilicic acid is reacted with aqueous ammonia to produce a solid silica product and a solution of ammonium fluoride. The solid silica is washed under controlled conditions and further processed to produce a high grade product. The ammonium fluoride solution is concentrated and sold as a concentrated ammonium fluoride solution product or reacted with metal hydoxides or oxides to produce metal fluorides.Type: GrantFiled: July 22, 1988Date of Patent: April 10, 1990Assignee: Freeport Research and Engineering Co.Inventors: Phillip D. Mollere, Tadeusz K. Wiewiorowski, Vivian C. Astley, Willis L. Thornsberry, Jr., Michael A. Murray
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Patent number: 4913966Abstract: This invention discloses novel, porous silica structures prepared from silica platelets. The structures are preferably prepared by spray-drying.Type: GrantFiled: April 22, 1987Date of Patent: April 3, 1990Assignee: Unilever Patent Holdings B.V.Inventors: Michael J. Garvey, Ian C. Griffiths
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Patent number: 4906446Abstract: Silica gels of a mean grain size of about 0.5 to 50 .mu.m are subjected to a heat or acid treatment that considerably reduces their surface area and the volume of pores smaller than 50 nm, while maintaining approximately the same grain size distribution and amorphous structure. These products are colorless and can be worked into a resinous molding material in relatively large quantities, especially as a filler for dental materials based on polymerizable monomers, in particular mono-, di- or polyfunctional esters of acrylic or methacrylic acid. In the completely hardened condition, these materials have good mechanical characteristics, less polymerization shrinkage, very low thermal expansion coefficients, excellent transparency and tooth similarity resulting from the favorable refractive index of the filler, as well as very good ability to be polished and abrasion resistance.Type: GrantFiled: February 29, 1988Date of Patent: March 6, 1990Inventors: Jurgen Engelbrecht, Michael Gunther, Helmut von Wallis