Improvement of Dynamic Properties by Addition of Special Low Surface Silica

Fall 178^th Technical Meeting

 of the Rubber Division of the American Chemical Society, October 12^th – 14^th, 2010, Milwaukee, WI

 

Improvement of Dynamic Properties by Addition of

Special Low Surface Silica

Dr. Gerd Schmaucks

Elkem AS, Silicon Materials

Kristiansand, Norway

The addition of precipitated silica to rubber compounds leads to high viscosity and is associated with processing difficulties. In the vulcanizate, high heat build-up and a decrease in lifetime in dynamic applications are the consequences.

The development of a silica with a BET surface area of only 20 m²/g (trade name SIDISTAR^® R) allows high filler loadings and excellent fatigue life, as confirmed by results from de Mattia tests.  This is due to easy dispersion down to the spherical primary particles of a mean particle size of 150 nm, which then act as ball-bearings.

The processing of these compounds is excellent, again due to the spherical shape of the primary particles helping to achieve improved dispersion of the reinforcing filler.

Of great interest to the end-user are the improvements in thermal stability and chemical resistance when this silica type is used, replacing traditional processing additives.

Applications include timing belts, anti-vibration pads and conveyor belts.