Evonik Degussa Gmbh

Degussa Aktiengesellschaft

Degussa - Huls Ag

Degussa Gmbh

Mario Scholz

Juergen Meyer

Jürgen Meyer

Christian Panz

Michael Kempf

Helmut Mangold

Kai Schumacher

Karl Meier

Dieter Kuhn

Steffen Hasenzahl

Uwe Schachtely

Markus Ruf

Helga Obladen

Rene Allerdisse

Georg Thiele

Ralf Schmoll

Eckehart Roland

Horst Zeizinger

Pia Buckel

Uwe Ellenbrand

Klaus Huthmacher

Klaus Deller

Dieter Kerner

Horst Weigel

Hans Joachim Hasselbach

Rainer Golchert

Andreas Freund

Günther Michael

Ralph McIntosh

Bernd Drapal

Uwe Diener

Elfriede Sextl

Matthias Rochnia

Andreas Hille

Ulrich Boes

Nongyuan Shi

Helmut Roth

Gerard Richet

Hans Lansink-Rotgerink

Werner Michel

Sems Yonsel

James Toth

Matt Romaine

Guido Titz

Matthew Romaine

Thomas Welker

Andrea Tietze

Aziz El Moussaoui

Gerald Wissler

Juergen Heym

Kenichi Kawamoto

Tien Le Quang

Wiltrud Schaffer-Treffenfeldt

Guenther Kunz

René Allerdisse

Meyer Jürgen

James J Toth

A precipitated silica having an SiOHabsorbance ratio of greater than or equal to 1.5, a silanol group density of 1 to 3.0 SiOH/nm, a modified tapped density of 1 to 50 g/l, and a pH of 3-5, when measured as a aqueous suspension of 5.00 g of the precipitated silica in 100 ml. of deionized water allows preparation of storage-stable RTV-1 silicone rubber formulations without stabilizer. A process for preparing the precipitated silica and its use in thickening sealants is provided.

Precipitated silicas for storage-stable RTV-1 silicone rubber formulations without stabilizer

Silicone rubber containing structurally modified hydrophobic pyrogenic silica.

Silicone rubber

Fumed silica having a BET surface area of 200&#xb1;15 m2/g, a grindometer value of less than 30 &#x3bc;m and a median value by PCS of 65 to 85 nm is prepared by grinding a fumed silica having a surface area of 200&#xb1;25 m2/g, and silicone rubber containing this silica.

Fumed silica

Surface-modified, structurally modified fumed silicas Surface-modified, structurally modified fumed silicas are surface-modified with N-containing silicon compounds. They are used as fillers in resins and adhesives.

Surface-modified, structurally modified fumed silicas

Hydrophilic precipitated silicas which combine a particularly low initial moisture content with low moisture absorption over time, a low tapped density and a low silanol group density, have the following physicochemical parameters: equilibrium moisture content (at 70% relative humidity/20&#xb0; C.) of 0.5%-5.0% by weight, based on the weight of the hydrophilic precipitated silica, BET surface area of 50-250 m/g, CTAB surface area of 50-250 m/g, and DBP (anhydrous) of 200-350 g/100 g.

Hydrophilic silica for sealants

Fumed silanized silica with the following physico-chemical data: Grindometer value less than 20 .mu.m Tamped density 25 to 85 g/l is prepared by grinding fumed silica which has been silanized. It can be used in silicone rubber.

Fumed silanized silica

Surface-modified, pyrogenically prepared silica is prepared by subjecting the pyrogenically prepared silica, which is in the form of aggregates of primary particles having a BET surface area of 300&#xb1;25 m/g and the aggregates have an average area of 4800-6000 nm, an average equivalent circle diameter (ECD) of 60-80 nm and an average circumference of 580-750 nm, to surface-modification in a known way. It can be used as a filler for controlling the rheology of liquid silicone rubber (LSR) systems.

Surface-modified, pyrogenically prepared silicas

Surface-modified, pyrogenically prepared silica is prepared by subjecting the pyrogenically prepared silica, which is in the form of aggregates of primary particles and possesses a BET surface area of 150&#xb1;15 m/g, the aggregates having an average area of 12 000-20 000 nm, an average equivalent circle diameter (ECD) of 90-120 nm and an average circumference of 1150-1700 nm, to surface-modification in a known way. It can be used as a filler for thickening liquid systems.

Fumed silicon dioxide powder in the form of aggregated primary particles having a BET surface area of 175&#xb1;15 m/g and a thickening effect, based on the BET surface area, of greater than 18 mPas g/mis hydrophobicized with polydimethylsiloxane. This hydrophobic fumed silica has a BET surface area of 110&#xb1;25 m/g. It can be used in epoxy resins. These epoxy resins in turn can be used as adhesives.

Silica and also epoxy resins

Thermoplastic elastomer, which comprises a fumed, hydrophilic or hydrophobic silica, which has been structurally modified and also a process for the improvement of the mechanical properties of thermoplastic elastomers. The thermoplastic elastomers are produced by preparing a masterbatch from the components (e.g. thermoplastic resin component and fumed silica) and compounding this with further thermoplastic elastomers.

Thermoplastic elastomers

Adhesive and sealant systems Adhesive and sealant systems on the basis of unsaturated polyester resins, epoxy resins, polyurethane, silane-terminated polymers, vinyl ester resins, acrylates, polyvinyl acetate, polyvinyl alcohol, polyvinyl ethers, ethylene-vinyl acetate, ethylene-acrylic acid copolymers, polyvinyl acetates, polystyrene, polyvinyl chloride, styrene-butadiene rubber, chloroprene rubber, nitrile rubber, butyl rubber, polysulphide, polyethylene, polypropylene, fluorinated hydrocarbons, polyamides, saturated polyesters and copolyesters, phenol-formaldehyde resins, cresol-/resorcinol-formaldehyde resins, urea-formaldehyde resins, melamine-formaldehyde resins, polyimides, polybenzimidazoles or polysulphones and containing 1% to 15% by weight of a hydrophilic fumed silica structurally modified by grinding.

Adhesive and sealant systems

The invention provides structurally modified, pyrogenically prepared silicas obtained by reaction of pyrogenic silicas with cyclic polysiloxanes of the type &#x2014;[O&#x2014;Si(R)]&#x2014;, where R is a C1 to C6 alkyl group and n is 3 to 9, and subsequent structural modification of the silanized silicas obtained. The invention further provides an adhesive comprising the structurally modified, pyrogenically prepared silicas.

Silicas

RTV two-component silicone rubber which contains structurally modified hydrophobic fumed silicas which have vinyl groups fixed on the surface, further hydrophobic groups, such as trimethylsilyl and/or dimethylsilyl and/or monomethylsilyl groups, additionally being fixed on the surface.

RTV two-component silicone rubber

Silicone rubber containing a fumed silica doped with potassium by means of aerosol.

The present invention relates to a hydrophobic, fumed silica which is obtained by reacting fumed silicas with cyclic polysiloxanes of the type &#x2014;[O&#x2014;SiR]&#x2014;, where R is a Cto Calkyl group and n is 3 to 9, and subsequently milling the silanized silicas obtained, and to a process for the preparation of the silica according to the invention, and to silicone rubber materials containing the silica according to the invention.

Hydrophobic fumed silica and silicone rubber materials containing the fumed silica

Growing community of inventors

Gruendau, Germany

Mario Scholz