The Buna SE product group of LANXESS comprises the general purpose emulsion styrene-butadiene rubbers (E-SBR) which is one of the most important types of synthetic rubber. Emulsion Styrene Butadiene Rubber is the most widely used rubber in the world, representing about 40% of the synthetic rubber market, which is a result of its excellent balance of properties and cost performance.

A typical E-SBR has 23,5% styrene, 10% cis1,4-, 75% trans1,4- and 15% vinyl1,2- polybutadiene, with random distribution of the monomers in the polymer chain. Increasing the styrene content the processability is improved, as also is the tensile strength, but the resistance to low temperature and wear deteriorates. E-SBR presents a broad molecular weight distribution and a high degree of branching, so it processes easier than solution SBR.

Buna SE is produced by a cold (5 to 10°C) free radical polymerization mechanism, in which the monomers are emulsified in an aqueous medium with rosin and/or fatty acids. The monomers react and form a latex, which is then coagulated to generate the solid rubber. The products are available in clear or oil extended grades, with staining or non staining antioxidant.

Buna SE presents good mechanical properties, abrasion and tear resistance, being largely used in tire, retread, footwear soles, hoses, tubes, cables, conveyor belts and a great variety of moulded, calendered and extruded rubber goods. More than half of the world production of E-SBR is used principally in general purpose tires.

The Buna SE product portfolio contains adjusted types which fullfill the actual requirements for the tire industry in regard of environment friendly oils. Different stabilisation systems allows the customer to use the products in color sensitive applications.

Name    ML 1+4    styrene (%)    oil (type)    stabilisation
Buna SE 1500    52    23,5    -    staining
Buna SE 1502    52    23,5    -    non-staining
Buna SE 1502 H    53    23,5    -    non-staining
Buna SE 1502 L    49    23,5    -    non-staining
Buna SE 1712 TE    52    23,5    TRAE    staining
Buna SE 1721 TE    55    40,0    TRAE    staining

TRAE = Treated Residual Aromatic Extract