Wacker-chemie Gmbh

Matthias Wolfgruber

Bernward Deubzer

Volker Frey

Karl Braunsperger

Rudolf Braun

Helmut Oswaldbauer

Herbert Sollradl

Ulrich Demlehner

Bernward Beubzer

Organosols of organopolysiloxanes are prepared by adding water-soluble organic solvents or mixtures thereof or water-soluble mixtures of water-soluble and water-insoluble organic solvents to aqueous, colloidal suspensions of organopolysiloxanes obtained by adding at least one alkoxysilane and/or the partial hydrolyzate thereof, and, if appropriate, mixed with an organo(poly)siloxane free of alkoxy groups and having a maximum of 8 siloxane units per molecule, to water in the presence of emulsifiers at a maximum rate of 5 moles of organosilicon compound per hour and per liter of water, and subsequently removing the water by distillation.

Organosols of organopolysiloxanes and a process for preparing the same

Aqueous dispersions of organopolysiloxanes containing the following components:

Aqueous dispersions of organopolysiloxanes

Structures of inorganic fibers which may contain inorganic particles, flakes or powders, are prepared by adding aqueous silicone resin emulsions containing curing catalysts and emulsifiers to the fiber material, shaping the treated fiber material, and subsequently curing the silicone resin, in which salts or chelates of trivalent iron are employed as the curing catalysts. Iron (III) acetylacetonate is preferably employed as the curing catalyst. The structures are preferably produced in a continuous process in which the aqueous silicone resin emulsion is sprayed onto the fiber material, then the fiber material is compacted to the desired bulk density and the silicone resin is cured by contacting the compacted fiber material with hot gases. Curing of the silicone resin is preferably carried out at a temperature of from 150.degree. to 300.degree. C. over a period of from 5 to 8 minutes.

Process for preparing structures of inorganic fiber material containing

Silicone resin powders are obtained by spray drying aqueous colloidal suspensions of organopolysiloxanes which are prepared by adding an alkoxysilane and/or a partial hydrolysate thereof and, if appropriate, mixed with an organo(poly)siloxane which is free of alkoxy groups and contains a maximum of 8 siloxane units per molecule, to water in the presence of an emulsifier at a maximum rate of 5 moles of organosilicon compound per hour per liter of water.

Silicone resin powder and a process for preparing the same

Colloidal suspensions of organopolysiloxanes are prepared by mixing an organosilicon compound selected from the group consisting of mixtures of alkoxysilanes and/or partial hydrolysates thereof and an organo(poly)siloxane which is optionally free of alkoxy groups and contains a maximum of 8 siloxane units, which is mixed with at least one alkoxysilane and/or a partial hydrolysate thereof, with water in the presence of an emulsifier, at a maximum rate of 5 moles of organosilicon compound per hour per liter of water, in which the organosilicon compound and the water is fed continuously, but separately from one another, into a reactor, in which at least one of the two substances contains an emulsifier, while the alkanol is being continuously removed by distillation from the aqueous suspension continuously emerging from the reactor. The aqueous suspension from which the alkanol has been removed by distillation is, if desired, recycled back into the reactor. A tubular reactor is preferably employed in which the water is added continuously at, or near the upper end of the tubular reactor and the organosilicon compound is added via several inlet points arranged along the longitudinal axis of the tubular reactor.

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Burghausen, Germany

Matthias Wolfgruber