Appeal 2006-2186
Application 09/991,640
INTRODUCTION
The claims are directed to precipitated silica having particular
characteristics and various methods of making and using the precipitated
silica. Claims 1 and 5 are illustrative:
1. A precipitated silica having the following physico-chemical
characteristics:
pH (5% in water) (ISO 787-9) 3-8
BET surface area (DIN 66131) (m2/g)400 - 600
DBP absorption value (DIN 53601, in relation to dried substance) (g/100 g)>380 – 420
Tapped density (ISO 787-11) (g/1)100 - 200
ALPINE sieve residue >63µ (ISO 8130-1) (%)0.1 - 40
5. A process for manufacturing a precipitated silica, which
comprises:
while stirring water in a vessel with a force sufficient to subject the
medium to shear containing water heated to 35oC to 45oC,
a) adding water and sulfuric acid together within at least 100 minutes,
to the vessel and maintaining a pH of 6-7, wherein the addition of substances
is interrupted for 60 to 120 minutes and when the addition of the substances
to the vessel has been completed, a solids content of 36 to 42 g/l remains;
and
b) filtering the solid matter, washing the filter cake and subjecting the
solid material to a short retention drying process,
wherein the precipitated silica has the following physico-chemical
characteristics:
pH (5% in water) (ISO 787-9) 3-8
BET surface area (DIN 66131) (m2/g)400 - 600
DBP absorption value (DIN 53601, in relation to dried substance) (g/100 g)>380 – 420
Tapped density (ISO 787-11) (g/1)100 - 200
ALPINE sieve residue >63µ (ISO 8130-1) (%)0.1 - 40
2
Page: Previous 1 2 3 4 5 6 7 8 Next
Last modified: November 3, 2007