Partially hydrophobic precipitated silicas

US6191122A · kind A · utility

Assignee

• Degussa-Huels AG · DE

Inventors

• Heinz-Gunter Lux · Großkrotzenburg, DE
• Karl Meier · Bornheim, DE
• Astrid Muller · Gelnhausen, DE
• Rolf Oelmuller · Hanau, DE
• Anja Ramb · Rodenbach, DE

Key dates

• Filing date: Mar 28, 1997
• Grant date: Feb 20, 2001
• Expiry date: Mar 28, 2017

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C01P2006/90
• WIPO field: Basic materials chemistry
• WIPO sector: Chemistry

Abstract

A partially hydrophobic precipitated silica having a methanol wettability of 10 to 49%, in particular with a DBP uptake on a dry basis of greater than 250 g/100 g and a mean particle size of 1 to 12 .mu.m and/or a carbon content of 0.3 to 1.85% and/or a loss on drying of 2.6 to 10.0% and/or a pH value of 5.5 to 10.0, is prepared by mixing the amount of water-repellent agent with the precipitated silica suspension at very short residence time and low pH value, filtering off the solid substance, washing free of salt, drying, post-treating thermally and milling. The partially hydrophobic precipitated silica can be used in active substance formulations and active substance formulations of hydrolysis-sensitive substance and in defoaming agents.