SILICA AND ALSO EPOXY RESINS

• US 20100286311A1
• Filed: 02/10/2009
• Published: 11/11/2010
• Est. Priority Date: 03/04/2008
• Status: Active Grant

• Current Assignee: Evonik Operations GmbH (Rag-Stiftung)
• Original Assignee: Evonik Degussa GmbH
• Inventors: Hille, Andreas, Scholz, Mario, Meyer, Juergen, Buckel, Pia
• Granted Patent: US 8,480,846 B2
• Time in Patent Office: Days
• US Class Current: 523/466
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C01B 33/183 by oxidation or hydrolysis in the vapour phase of silicon compounds such as halides, trichlorosilane, monosilane
• CPC Class Codes: C01P 2004/64 Nanometer sized, i.e. from 1-100 nanometer
• CPC Class Codes: C01P 2006/11 Powder tap density
• CPC Class Codes: C01P 2006/12 Surface area
• CPC Class Codes: C01P 2006/22 Rheological behaviour as dispersion, e.g. viscosity, sedimentation stability
• CPC Class Codes: C08K 3/36 Silica
• CPC Class Codes: C08L 63/00 Compositions of epoxy resins; Compositions of derivatives of epoxy resins
• CPC Class Codes: C09C 1/30 Silicic acid
• CPC Class Codes: C09C 1/3081 Treatment with organo-silicon compounds
• CPC Class Codes: C09J 163/00 Adhesives based on epoxy resins; Adhesives based on derivatives of epoxy resins
• CPC Class Codes: Y02P 20/129 Energy recovery, e.g. by cogeneration, H2recovery or pressure recovery turbines
• CPC Class Codes: Y10T 428/2995 Silane, siloxane or silicone coating

Abstract

Fumed silicon dioxide powder in the form of aggregated primary particles having a BET surface area of 175±15 m²/g and a thickening effect, based on the BET surface area, of greater than 18 mPas g/m² is hydrophobicized with polydimethylsiloxane. This hydrophobic fumed silica has a BET surface area of 110±25 m²/g. It can be used in epoxy resins. These epoxy resins in turn can be used as adhesives.

Claims

1. Fumed silicon dioxide powder in the form of aggregated primary particles having a BET surface area of 175±

15 m²/g and a thickening effect, based on the BET surface area, of greater than 18 mPas·

g/m².

3. Process for preparing the hydrophobic fumed silica according to claim 2, characterized in that the hydrophilic fumed silica according to claim 1 is sprayed with polydimethylsiloxane, followed by mixing and then heat treatment for 1 to 6 hours.

2. Hydrophobic fumed silica characterized in that it has been hydrophobicized with polydimethylsiloxane and has a BET surface area of 110±

25 m²/g.

4. Epoxy resins characterized in that they comprise the hydrophobic fumed silica according to claim 2.

5. Use of the epoxy resins according to claim 4 as adhesives.

6. Adhesives characterized in that they comprise the hydrophobic fumed silica according to claim 2 and are based on epoxy resins.