Novel Functionalized Oil Extended SSBR for Silica & Carbon Black Containing Tires

Novel Functionalized Oil Extended SSBR for Silica & Carbon Black Containing Tires
The global reduction of CO₂ emission became a central task for the world economy. Therefore an increasing number of national countries enforce legislation to accelerate the commercialization of less energy and fuel consuming technological options.
Thus, legislative regulations and rising oil prices pressure automobile producers and tire producers to come up with long life, fuel saving and safe solutions. Accordingly, there is the need for tires with low rolling resistance combined with excellent wet grip and abrasion performance characteristics.
An important precondition for the production of automobile tires, especially, high performance tires with low rolling resistance and well balanced wet skid resistance properties, consists in the application of functionalized solution butadiene-styrene rubber (SSBR).
The interaction of functionalized rubbers with silica and carbon black filler has been investigated extensively by Dow Synthetic Rubber and has led to the development of clear (oil-free) chain-end modified polymers in a typical molecular weight range from 250.000 to 550.000 g/mol (Mw). Efficient chain-end modification improved the interaction of polymers with silica and carbon black in rubber compound vulcanizates. The rolling resistance of silica and/or carbon black containing tires was significantly decreased [1,2].
The development of high molecular weight oil extended functionalized rubber (Mw > 550.000 g/mol) for use in carbon black containing tires or for use in “Green Tires”, which are substantially based on silica filler, required a polymer backbone modification mechanism.  
Novel backbone functionalized oil containing solution-styrene butadiene copolymers were compounded and vulcanized and extensively characterized.
As one result of our developmental work, modified oil extended polymers are available which enabled an improvement of the rolling resistance property in silica and in carbon black compound vulcanizates by up to 25% when compared with non-modified oil extended SSBR grade properties. Furthermore, the excellent wet grip, ice grip, abrasion and heat built up properties of the functionalized polymer grade in silica and carbon black containing compound vulcanizates could be improved significantly. 

References:
[1] Polymer Functionalization - Novel Rubber for Tire Tread Application
      Thiele, S. K.H., Bellgardt, D., Holzleg, M., Kautschuk Gummi Kunststoffe (KGK), 5 (2008), 244
[2] Novel Functionalized SSBR for Silica Containing Tires (Paper 91)
      Thiele, S. K.H., Bellgardt, D., Holzleg, M.,
      Published at the Conference of the Rubber Devision of thee ACS at the Fall 172nd Technical Meeting & IRC 2007 at Cleveland, OH, USA on October 16-19, 2007.