Method for preparing hydrophobic fumed silica
US5919298A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 12, 1998 |
| Grant date | Jul 6, 1999 |
| Priority date | — |
| Expiry date | Jan 12, 2018 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC01P2006/90
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
A method for the preparation of hydrophobic fumed silicas which are useful, for example, as reinforcing fillers in rubber compositions. The method comprises two steps, where in the first step an aqueous suspension of fumed silica is contacted with an organosilicon compound in the presence of a catalytic amount of an acid to effect hydrophobing of the fumed silica. In the preferred method the first step is conducted in the presence of a water miscible organic solvent which facilitates hydrophobing of the fumed silica with the organosilicon compound and the fumed silica has a BET surface area greater than 50 m.sup.2 /g. In the second step the aqueous suspension of the fumed silica is contacted with a water-immiscible organic solvent at a solvent to silica weight ratio greater than 0.1:1 to effect separation of the hydrophobic fumed silica from the aqueous phase. In a preferred process the hydrophobic fumed silica has a surface area within a range of about 100 m.sup.2 /g to 750 m.sup.2 /g.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.