Pq Corporation

Dow Corning Corporation

Bruce W Sands

John C Saam

James P Cunnion, Jr

Robert J Nehring, Jr

A method of producing hydrophobic colloidal silica is disclosed. The method comprises combining an aqueous colloidal silica dispersion, polyorganosiloxane, and anionic surfactant to yield a stable aqueous emulsion of hydrophobic colloidal silica. The emulsion may be further processed by evaporating the water to yield a white material which may be easily ground to a fine powder of hydrophobic colloidal silica. This powder is useful as a reinforcement for silicone rubber.

Method of hydrophobing silica

Various type A zeolites can be combined with thermoplastic materials to provide antiblock and improved optical properties to films or sheets of said thermoplastic. The zeolites are of less than full hydration, and at least a portion of the sodium is replaced with multivalent ions such as calcium and magnesium. The zeolites can also be acid treated to provide zeolites that contain hydronium ions.

Thermoplastic materials

Water-based explosives that use siliceous boron-containing microspheres as sensitizing agents are stabilized by adding multivalent metal ions to the explosives. Zinc salts are especially useful.

Explosive systems

Hollow microspheres of reduced surface energy and reactivity and of improved packing and sphericity are prepared by simultaneously forming said microspheres and reacting them with an organosilicon compound. The microspheres are prepared by spray drying a solution of alkali metal silicate and a 'polysalt.' The organosilicon is present as the microspheres are formed, penetrates and reacts to form a shell consisting of a silicate, polysalt and the organosilicon compound. The resulting product is more discrete, more free-flowing, has better packaging characteristics, improved packing factor and improved filler properties when compared to prior-art microspheres.

Hollow microspheres with organosilicon-silicate walls

A simplified method of manufacturing a silicon elastomeric foam comprises mechanically generating a stable froth of an aqueous silicone emulsion, while adding surfactant and thickener, then removing the water from the stable froth. The emulsion consists essentially of anionically stabilized hydroxyl endblocked polydiorganosiloxane, colloidal silica, an organic tin compound, and water, the emulsion having a pH in the range of 9 to 11.5 inclusive. The dried foam is an elastomeric, cellular structure possessing typical silicone elastomer heat stability.

Elastomeric foam

More perfect, less porous hollow microspheres can be prepared by spray-drying dispersions of alkali metal silicate and 'polysalt' that contain certain organic liquids. The organics are water-miscible and have boiling points of 100.degree. C. or more. The solvent is added just prior to spray drying and the resulting product has fewer cracks and/or holes.

Manufacturing process for hollow microspheres

More perfect, less porous hollow microspheres can be prepared by spray-drying dispersions of film-forming solids that contain certain organic solvents. The organic solvents are water-miscible and have boiling points of 100.degree. C. or more. The solvent is added just prior to spray drying and the resulting product has fewer cracks and/or holes. This improvement is especially beneficial to preparation systems involving alkali metal silicates and 'polysalts.'

Growing community of inventors

Malvern, PA, United States of America

Bruce W Sands