Precipitated silicas having high structure and process for their preparation

US4495167A · kind A · utility

Assignee

• Degussa AG · DE

Inventors

• Peter Nauroth · Wesseling, DE
• Heinz Esch · Wesseling, DE
• Gunter Turk · Hanau, DE

Key dates

• Filing date: Nov 2, 1982
• Grant date: Jan 22, 1985
• Expiry date: Nov 2, 2002

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C01P2006/40
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

There are disclosed precipitated silicas which are characterized by the following physical-chemical data: ______________________________________ A B C ______________________________________ BET-surface area m.sup.2 /g 400-600 400-600 400-600 according to DIN 66131 DBP-Number % 340-380 320-360 310-360 Bulk density according g/l 180-220 75-120 35-70 to DIN 53194 "ALPINE-Sieve Wt. % 25-60 <0.1 <0.01 Residue" >63 m.mu. ______________________________________ Depending on the particle distribution curve, these precipitated silicas can be employed as silica carriers for active materials of all types, as antiblocking agents for polypropylene and polyethylene films, as thickening silica in specific polar systems in which pyrogenic silicas show little thickening capacity, as highly active matting agents for varnishes and as catalyst carriers as well as insulating materials. The precipitated silicas are produced by establishing a silica final concentration of 46 grams/l in a receiver having water present heated to a temperature of 40.degree.-42.degree. C. while holding the pH constant in the range of 6-7 by simultaneously running in a water glass solution and sulfuric acid while maintaining s…