Buna SE 1723 is a styrene-butadiene copolymer with a bound styrene content of 23.5%, produced by cold emulsion polymerization (10℃ maximum) using a mix of rosin and fatty acid soaps as emulsifier, extended in TDAE oil with a PCA less than 3,0 % and PAHs content less than 10 ppm which is compliant with the European Directive 2005/69/EC. The monomers are randomly distributed in the polymer structure, while the butadiene fraction is found in its major part in the trans configuration with small fractions of cis and vinyl configurations. CAS No.: 9003-55-8. The rubber is protected by a staining stabilizer system.