Doped precipitated silica

US6800267B2 · kind B2 · utility

Assignee

• Degussa AG · DE

Inventors

• Jurgen Schubert · Dirmstein, DE
• Klaus-Dieter Hellwig · Bad Honnef, DE
• Astrid Muller · Gelnhausen, DE

Key dates

• Filing date: Aug 29, 2001
• Grant date: Oct 5, 2004
• Expiry date: Jun 4, 2022

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10T428/2982
• WIPO field: Textile and paper machines
• WIPO sector: Mechanical engineering

Abstract

Aluminum-doped precipitated silicas having a BET surface area of more than 300 m2/g and aluminum distributed uniformly in the silica particles are prepared by sequentially heating a mixture of water and sodium silicate at a temperature of from 70 to 86° C. and adding sulfuric acid until half of the sodium silicate is neutralized, then aging the mixture for a time of from 30 to 120 minutes, adjusting the pH of the mixture with sulfuric acid to a range of from 3.0 to 7.0, thereby precipitating the aluminum-doped silica, filtering the aluminum-doped silica from the mixture to form a filtercake and washing the filtercake, followed by drying and/or grinding the washed filtercake. An aluminum salt solution is metered into the mixture at step a) and/or step c). The aluminum-doped precipitated silicas of the present invention may be used in coatings for paper and other media intended for ink jet printing.