Patents by Inventor James Richard Hahn
James Richard Hahn has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Chemically modified silica fillers, process for producing, and silicone compositions containing same
Patent number: 6384125Abstract: This invention is a process for making modified silica filler comprising the steps of: (A) contacting an acidic aqueous suspension of precipitated or colloidal silica, optionally in the presence of a surfactant and/or a water-miscible solvent, with a combination of (a) a functionalizing coupling agent, and (b) an organometallic hydrophobing compound in a weight ratio of (a) to (b) of at least 0.001 to 1 to form an acidic aqueous suspension of chemically treated silica filler having a pH of 2.0 or less (B) treating the acidic aqueous suspension of the chemically treated filler with an acid-neutralizing agent to increase the pH of the suspension to a range of from greater than 2.0 to 10, and (C) recovering the chemically treated filler. This invention is also modified silica filler that has a pH of from about 5.0 to 10.0, where the silica filler is made by the method of this invention.Type: GrantFiled: August 11, 2000Date of Patent: May 7, 2002Assignee: Dow Corning CorporationInventors: Debora Frances Bergstrom, Lisa Marie Boswell, Mark David Fisher, James Richard Hahn, Timothy A. Okel, Clifford Carlton Reese -
Patent number: 6239243Abstract: 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.Type: GrantFiled: June 10, 1999Date of Patent: May 29, 2001Assignee: Dow Corning CorporationInventors: Qin Deng, James Richard Hahn, Kiersten Lynn Shephard
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Patent number: 6184408Abstract: A method for the preparation of hydrophobic precipitated silica. The method comprises contacting an aqueous suspension of a hydrophilic precipitated silica with (1) a catalytic amount of an acid and (2) an organosilicon compound in the presence of (3) a water-miscible organic solvent in an amount sufficient to facilitate reaction of the hydrophilic precipitated silica with the organosilicon compound to form a hydrophobic precipitated silica.Type: GrantFiled: April 28, 1999Date of Patent: February 6, 2001Assignee: Dow Corning CorporationInventors: Gary Thomas Burns, Qin Deng, James Richard Hahn, Thomas G. Krivak, Timothy A. Okel, Clifford Carlton Reese
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Patent number: 6107351Abstract: 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: GrantFiled: February 23, 1998Date of Patent: August 22, 2000Assignee: Dow Corning CorporationInventors: Gary Thomas Burns, Qin Deng, James Richard Hahn, Clifford Carlton Reese
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Patent number: 6051672Abstract: A method for making hydrophobic non-aggregated colloidal silica comprising reacting an aqueous suspension of a hydrophilic non-aggregated colloidal silica having an average particle diameter greater than about 4 nm with a silicon compound at a pH less than about pH 4 in the presence of a sufficient quantity of a water-miscible organic solvent to facilitate contact of the hydrophilic non-aggregated colloidal silica with the silicon compound. The method is conducted at a temperature within a range of about 20.degree. C. to 250.degree. C. for a period of time sufficient to form a hydrophobic non-aggregated colloidal silica. The hydrophobic non-aggregated colloidal silicas prepared by the present method are particularly useful as fillers in silicone compositions such as adhesives, rubbers, and sealants.Type: GrantFiled: August 24, 1998Date of Patent: April 18, 2000Assignee: Dow Corning CorporationInventors: Gary Thomas Burns, Jon Vierling DeGroot, Jr., James Richard Hahn, Daniel Anton Harrington, Patricia Ann Moore
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Patent number: 6013187Abstract: A method for removing metal contaminates from solution using mercapto-functional silica xerogels. The mercapto-functional silica xerogels are characterized by having a surface area greater than 365 m.sup.2 /g, an average pore diameter of at least 6 nm, and a pore volume of at least 2 cm.sup.3 /g. The mercapto-functional silica xerogels are particularly useful for removing Group VIII metals such as platinum from solutions comprising polyorganosiloxane fluids and resins.Type: GrantFiled: August 31, 1998Date of Patent: January 11, 2000Assignee: Dow Corning CorporationInventors: Gary Thomas Burns, Qin Deng, James Richard Hahn, Guy Leo Reggio, Kai Su
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Patent number: 5942590Abstract: The present invention is hydrophobic silica gels having a reduced surface area and a method for their preparation under neutral conditions. The method comprises two steps, where in the first step the pH of a mixture comprising a silica hydrosol and colloidal silica is adjusted with a base to within a range of pH 3 to pH 6 to facilitate formation of a silica hydrogel having incorporated therein colloidal silica. In the second 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 gel 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 process the hydrophobic silica gel is contacted with a sufficient quantity of a water-immiscible organic solvent to convert the hydrophobic silica hydrogel into a hydrophobic silica organogel.Type: GrantFiled: February 11, 1998Date of Patent: August 24, 1999Assignee: Dow Corning CorporationInventors: Gary Thomas Burns, Qin Deng, James Richard Hahn, Clifford Carlton Reese
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Patent number: 5807501Abstract: The present invention is neutral-aged hydrophobic organosilicate-modified silica gels and a method for their preparation. The method comprises three steps, where in the first step an organosilicate-modified silica hydrosol is contacted with a strong mineral acid at a pH less than about 1 to form an organosilicate-modified silica hydrogel. In the second step the organosilicate-modified silica hydrogel is aged at a pH within a range of about pH 3.5 to pH 8. In the third step the neutral-aged organosilicate-modified silica hydrogel is contacted with an organosilicon compound in the presence of a catalytic amount of a strong acid to effect hydrophobing of the organosilicate-modified silica hydrogel to form a hydrophobic organosilicate-modified silica hydrogel having a surface area within a range of about 100 m.sup.2 /g to 750 m.sup.2 /g in the dry state.Type: GrantFiled: February 20, 1997Date of Patent: September 15, 1998Assignee: Dow Corning CorporationInventors: Gary Thomas Burns, Qin Deng, James Richard Hahn, Clifford Carlton Reese
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Patent number: 5789495Abstract: The present invention is hydrophobic organosilicate-modified silica gels and a method for their preparation under neutral conditions. The method comprises two steps, where in the first step the pH of an organosilicate-modified silica hydrosol is adjusted with a base to within a range of about pH 3 to pH 7 to facilitate formation of an organosilicate-modified silica hydrogel. In the second step the organosilicate-modified silica hydrogel is contacted with an organosilicon compound in the presence of a catalytic amount of a strong acid to effect hydrophobing of the organosilicate-modified silica hydrogel to form a hydrophobic organosilicate-modified silica gel having a surface area within a range of about 100 m.sup.2 /g to 850 m.sup.2 /g in the dry state.Type: GrantFiled: February 24, 1997Date of Patent: August 4, 1998Assignee: Dow Corning CorporationInventors: Gary Thomas Burns, Qin Deng, James Richard Hahn, Clifford Carlton Reese
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Patent number: 5789514Abstract: A method for the preparation of hydrophobic silica gels which are useful as reinforcing fillers in rubber compositions. The method comprises two steps, where in the first step a silica hydrosol is contacted with a sufficient concentration of a strong mineral acid at a pH less than about pH 1 to form a silica hydrogel. In the second step the silica hydrogel is contacted with described organosilicon compounds in the presence of a catalytic amount of a strong acid to effect hydrophobing of the silica hydrogel thereby forming a hydrophobic silica gel having a surface area within a range of about 100 m.sup.2 /g to 750 m.sup.2 /g as measured in the dry state. In a preferred method the hydrophobic silica hydrogel is contacted with a sufficient quantity of a water-immiscible organic solvent to convert the hydrophobic silica hydrogel into a hydrophobic silica organogel.Type: GrantFiled: February 24, 1997Date of Patent: August 4, 1998Assignee: Dow Corning CorporationInventors: Gary Thomas Burns, James Richard Hahn, Clifford Carlton Reese
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Patent number: 5750610Abstract: The present invention is hydrophobic organosilicate-modified silica gels and a method for their preparation. The method comprises two steps, where in the first step an organosilicate-modified silica hydrosol is heat treated in the presence of a strong mineral acid at a pH less than about pH 1 to form an organosilicate-modified silica hydrogel. In the second step the organosilicate-modified silica hydrogel is contacted with an organosilicon compound in the presence of a catalytic amount of a strong acid to effect hydrophobing of the organosilicate-modified silica hydrogel thereby forming a hydrophobic organosilicate-modified silica hydrogel having a surface area within a range of about 100 m.sup.2 /g to 750 m.sup.2 /g as measured in the dry state.Type: GrantFiled: February 24, 1997Date of Patent: May 12, 1998Assignee: Dow Corning CorporationInventors: Gary Thomas Burns, James Richard Hahn, Clifford Carlton Reese
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Patent number: 5708069Abstract: The present invention is hydrophobic silica gels and a method for their preparation under neutral conditions. The method comprises two steps, where in the first step the pH of a silica hydrosol is adjusted with a base to within a range of about pH 3 to pH 7 to facilitate formation of a silica hydrogel. In the second 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. In a preferred method, in a third step the hydrophobic silica gel is contacted with a sufficient quantity of a water-immiscible organic solvent to convert the hydrophobic silica hydrogel into a hydrophobic silica organogel.Type: GrantFiled: February 24, 1997Date of Patent: January 13, 1998Assignee: Dow Corning CorporationInventors: Gary Thomas Burns, Qin Deng, James Richard Hahn, Clifford Carlton Reese