COUPSIL® products leverage a combination of silica and functional silanes to optimize performance in rubber applications.


COUPSIL® is the brand name for a group of silane-modified silica products. These are ULTRASIL® precipitated silica products that have already been treated with silanes. They are used as reinforcing fillers in rubber compounds with various polymers, such as IR (isoprene rubber), SBR (styrene-butadiene rubber), BR (butadiene rubber) or NBR (nitrile butadiene rubber), and blends thereof.

The range of COUPSIL® products offers numerous solutions specifically designed for mechanical rubber goods such as seals and gaskets, conveyor belts, drive belts, roller coatings, and hoses. COUPSIL® products are also used for light-colored reinforcement systems in high-quality shoe soles, significantly improving their performance. These mechanical rubber goods often face dynamic stress and must withstand high loads.

Tear and abrasion resistance on a high level 
The products of the COUPSIL® family are available in powder or granulate form for easy handling and processing. They have several advantages: As they are pre-reacted products, there is no need for complex in-situ modification of silica in the mixer. In the presence of accelerators, they form strong rubber-to-filler bonds during vulcanization. As a result, the products are particularly tear and abrasion-resistant and have excellent dynamic properties, such as dynamic stiffness and damping behavior. In this way, COUPSIL® products shorten the compounding process without performance loss.

These systems also address sustainability goals, helping manufacturers reduce resource use by extending the service life of end products.

Depending on the type of rubber, the required reinforcement is reached by the right choice of COUPSIL® combination of silica and silanes. Evonik’s application engineers and technicians can help to select the right product for each application and develop tailor-made solutions with their customers.