Si 69®, Si 363® or a special compound?


All sulfur-functional silanes from Evonik are supplied in liquid form. For easier handling additional product solutions are available. Dry blends of our liquid silanes with carbon black can be handled like particulate fillers. Our COUPSIL® product range are pre-reacted silane with silica. They offer the possibility to use the Silica/Silane-system without the necessity to do the delicate chemical reaction of silica with silane, called silanization, in the mixer. Monofunctional silanes round off the product range as very effective processing agents. They reduce mixing viscosities and improve the processing of rubber compounds without the negative migration effect in rubber in contrast to many other processing aids.

Liquid rubber silanes portfolio

Liquid rubber silanes are products that can be injected to the compound in the mixer or added to the rubber compound in pre-weighed bags.

Dry blends of silane with carbon black

Rubber Silanes products in solid form can be used as dry blends with carbon black. The products are a 50:50 blend of the liquid silane with a N330 grade carbon black. They can be handled like carbon black.


In COUPSIL® products the silica is already pre-reacted with the silane. This makes the application of the Silica/Silane-system much simpler, because the complex silanization reaction in the mixer is obsolete. The product has only to be dispersed in the rubber like carbon black leading to significantly easier processing. Powder as well as granulates are available.


Adhesion of rubber to fabric or steel cord can be significantly improved with the so called RFS-system (Resorcinol Formaldehyde Silica). No dipping of the cord is necessary compared to the old RFL system. In COFILL® 11 we combine the resorcinol with the silica. The handling of COFILL® 11 is much safer than the handling of resorcinol alone but delivering the same excellent adhesion. It is used together with a formaldehyde donor like hexamethylene tetramine.

Manufacturing / ESHQ

Evonik manufactures rubber silanes in several locations worldwide.

Learn more about the handling and the legal classification of our rubber silanes.