What is SBR (styrene-butadiene rubber)?
SBR stands for styrene-butadiene rubber. It is a synthetic rubber and a copolymer of styrene and butadiene. Developed in the late 1920s, it was introduced in Germany under the trade name Buna S. Today, SBR is the world’s largest family of synthetic rubbers by production volume.
Roughly two thirds of SBR production goes into tyre manufacture. Other applications include conveyor belts, industrial hoses, shoe soles and floor coverings. SBR is also present in WARCO rubber tiles. The recycled tyre rubber granules used in the tiles come from end-of-life tyres, or ELT, and consist mainly of SBR and natural rubber. Here, SBR is not raw rubber. It forms part of a granulated tyre compound that has already been vulcanised.
SBR contributes to the elasticity of the rubber granules. However, the behaviour of a finished rubber tile depends on the interaction between the tyre compound, granule size, PU binder and compaction. SBR is more sensitive to ozone and UV radiation than EPDM because double bonds in its polymer chain are susceptible to attack. In two-layer tiles, an EPDM wear layer forms the upper surface. This layer provides the colour and is exposed to the weather, while the ELT rubber granules beneath form the elastic base.