The Lanxess Buna VSL portfolio offers solution styrene-butadiene rubbers that have different styrene and vinyl levels combined with varying Mooney viscosities. In contrast to emulsion SBR the molecular weight, molecular weight distribution, microstructure and branching can be controlled to produce polymers that offer improved end properties.

Solution SBRs are gradually replacing emulsion SBRs for special applications and particularly for summer and winter tire treads and low rolling resistance tires especially in the high performance sector. It is sometimes blended with NR, BR or emulsion SBR to improve the properties of the final product.
As a component in the polymer blend of car tire treads, grip and rolling resistance will be enhanced by controlling the Tg and shape of the tan delta curve.

Provided that the compounds are formulated and processed correctly, the vulcanizates have good resistance to reversion. The low temperature flexibility, resilience and abrasion resistance depend on the polymer's styrene and vinyl content.

Name    styrene (%)    vinyl (%)    ML1+4    oil (type)    oil (phr)    Tg (°C)
Buna VSL 2525-0 M    25    25    54    none    -    -49
Buna VSL 5025-0 HM    25    50    65    none    -    -22
Buna VSL 5025-2    25    50    47    TDAE    37,5    -29
Buna VSL 5025-2 HM    25    50    62    TDAE    37,5    -29
Buna VSL 5228-2    28    52    50    TDAE    37,5    -20
Buna VSL 2438-2 HM    38    24    80    TDAE    37,5    -29


Key Properties

• good resistance to reversion
• improved wet grip
• low hysteresis
• good resilience
• good abrasion resistance