Precipitated silicic acid

US6268424A · kind A · utility

Assignee

• Degussa AG · DE

Inventors

• Anke Blume · Lechenich, DE
• Burkhard Freund · Lechenich, DE
• Bernhard Schwaiger · Lechenich, DE
• Mustafa Siray · Hanau, DE
• Stefan Uhrlandt · Niederkassel, DE

Key dates

• Filing date: Sep 3, 1999
• Grant date: Jul 31, 2001
• Expiry date: Sep 3, 2019

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02T10/86
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

Precipitated silica having the following parameters: BET surface area 80-180 m.sup.2 /g CTAB surface area 80-139 m.sup.2 /g BET/CTAB ratio 1.0-1.6 Sears No. (consumption of 5-25 ml 0.1 N NaOH) DBP No. 200-300 ml/100 g Al.sub.2 O.sub.3 content <5% wk coefficient <3.4 Degraded particles <1.0 .mu.m Non-degradable particles 1.0-100 .mu.m is prepared by reacting alkali silicate with mineral acids and aluminum sulfate solution at temperatures of 60-95.degree. C. at a pH of 7.0-10.0 while stirring constantly, wherein the reaction is continued to a solids concentration of 40-110 g/l, the pH is adjusted to a value between 3 and 5, and the precipitated silica is filtered off, washed and then dried, and optionally ground or granulated.