Dow Corning Corporation

Qin Deng

James Richard Hahn

Clifford Carlton Reese

Gary Thomas Burns

Gary T Burns

Nick Evan Shephard

Loren D Lower

Thomas G Krivak

Timothy A Okel

Kai Su

Richard Alan Palmer

Robert Harold Krahnke

Timothy B Lueder

Kiersten Lynn Shephard

Guy Leo Reggio

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.

Method for preparing hydrophilic silica gels with high pore volume

A room temperature vulcanizing (RTV) silicone composition curable in the presence of moisture with rapid development of green strength. The RTV silicone composition comprises (A) 0 to about 85 weight percent polydiorganosiloxanes comprising on average at least 1.2 chain terminations per molecule selected from the group consisting of hydroxysilyl groups and alkoxysilyl groups; (B) about 10 to 95 weight percent polydiorganosiloxanes comprising on average at least 1.2 chain terminations per molecule selected from the group consisting of hydroxysilyl groups, alkoxysilyl groups, and multi-alkoxysilyl groups, provided that at least one chain termination per molecule comprises a multi-alkoxysilyl group; (C) an effective amount of a condensation catalyst; (D) 0 to about 40 weight percent of an alkoxysilane; and (E) 0 to about 60 weight percent of a filler; provided that the sum of the weight percents of Components (A) and (B) comprises about 20 to 95 weight percent based on the total weight of the RTV silicone composition.

RTV silicone compositions with rapid development of green strength

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.

Method for preparation of hydrophobic precipitated silica

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.

Neutral-aged hydrophobic silica gels with reduced surface area

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.

Method for removing metal contaminants from solution using

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. A water soluble compound of cerium or iron may be added during conduct of the second step to improve heat stability of the hydrophobic silica gel.

Process for making hydrophobic silica with reduced surface area under

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. In a preferred process the hydrophobic organosilicate-modified silica hydrogel is contacted with a sufficient quantity of a water-immiscible organic solvent to convert the hydrophobic organosilicate-modified silica hydrogel into a hydrophobic organosilicate-modified silica organogel.

Neutral-aged hydrophobic organosilicate-modified silica gels

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. In a preferred process the hydrophobic organosilicate-modified silica hydrogel is contacted with a sufficient quantity of a water-immiscible organic solvent to convert the hydrophobic organosilicate-modified silica hydrogel into a hydrophobic organosilicate-modified silica organogel. A water soluble compound of cerium or iron may be added in the second step to improve the heat stability of the hydrophobic organosilicate-modified silica gel.

Method for making hydrophobic organosilicate-modified silica gels under

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.

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Midland, MI, United States of America

Qin Deng