Readily dispersible precipitated silica

US6180076A · kind A · utility

Assignee

• Degussa-Huels AG · DE

Inventors

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

Key dates

• Filing date: Sep 15, 1998
• Grant date: Jan 30, 2001
• Expiry date: Sep 15, 2018

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C01P2006/90
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

Precipitated silica, having the following physico-chemical parameters: BET surface area 120-300 m.sup.2 /g CTAB surface area 100-300 m.sup.2 /g BET/CTAB ratio 0.8-1.3 Sears index (consumption of 6-25 ml 0.1 N NaOH) DBP index 150-300 g/100 g wk coefficient <3.4 Particle size of the degraded <1.0 .mu.m particles Particle size of the non- 1.0-100 .mu.m degradable particles The precipitated silica is prepared by a process in which an alkali metal silicate (preferably soda water-glass) is reacted with mineral acids (preferably sulfuric acid) at temperatures of 60-95.degree. C. at a pH of 7.0-11.0 with continuous stirring, the reaction is continued up to a solids concentration of 40 g-110 g, the pH is adjusted to a value between 3 and 5, and the precipitated silica is filtered off, washed, then dried and, if appropriate, ground or granulated. The precipitated silica is employed as a filler in vulcanizable mixtures for the production of tires.