Precipitated silicas, a process for their preparation and their use in vulcanizable rubber mixtures

US5859117A · kind A · utility

Assignee

• Degussa AG · DE

Inventors

• Udo Goerl · Recklinghausen, DE
• Andrea Hunsche · Frechen, DE
• Robert Kuhlmann · Lechenich, DE
• Mustafa Siray · Hanau, DE
• Heinz Esch · Wesseling, DE

Key dates

• Filing date: Sep 16, 1997
• Grant date: Jan 12, 1999
• Expiry date: Sep 16, 2017

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08K2201/006
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

Precipitated silicas, characterized in that they have a CTAB surface area (in accordance with ASTM D 3765-92) of 200 to 400 m.sup.2 /g, a DBP index (in accordance with ASTM D 2414) between 230 and 380 ml/100 g as powder and 180-250 g/100 g as granulate, a silanol group density (V.sub.2 -NaOH consumption) of 20 to 30 ml and the following macropore size distribution which is typical of the surface area range involved, determined by means of Hg porosimetry (DIN 66 133) for specific pore size intervals (incremental mode of application): ______________________________________ CTAB surface CTAB surface CTAB surface area range: area range: area range: 200-250 m.sup.2 /g 250-300 m.sup.2 /g 300-400 m.sup.2 /g Pore size interval nm! Hg consumption in ml/g of silica ______________________________________ 10-20 0.27-0.49 0.35-0.50 0.32-0.42 20-30 0.22-0.32 0.15-0.30 0.17-0.22 30-40 0.15-0.21 0.12-0.17 0.12-0.15 40-50 0.11-0.16 0.09-0.12 0.08-0.11 50-60 0.08-0.12 0.06-0.10 0.06-0.09 ______________________________________