Kuraray’s liquid farnesene rubber used in SRI tyres for the first time

Kuraray’Sumitomo Rubber Industries, Ltd. (SRI) has used liquid farnesene rubber (LFR), a liquid rubber developed by Japanese chemicals manufacturer Kuraray, in its latest studles styre Winter Maxx 02. This marks the first time LFR has been used as a performance enhancing additive in the production of tyres.

Kuraray developed LFR by using a new biologically derived diene monomer called farnesene, developed by Amyris, Inc.Kuraray said it has discovered a variety of LFR’s unique advantages and will continue to optimise its molecular design to develop new applications that meet customers’ diverse performance requirements, going beyond tyres.

Kuraray entered a joint-development agreement with US biotechnology company Amyris, Inc. in 2011 and created technology that refines Amyris’s biomass material farnesene to a level of purity suitable for polymerisation as well as technology that synthesises LFR. They were able to discover relationships between various properties when combining LFR’s molecular structure with rubber compounds and began supplying LFR to tyre manufacturers.

Following the success of its partnership, in December 2016, Kuraray and Amyris signed a multi-year collaboration extension, which includes joint marketing of products to industry and end customers.

The company specially designed the LFR used in the Sumitomo Rubber’s latest studless tyre Winter Maxx 02. By combining the LFR with rubber compounds, the tyre’s ice grip performance at low temperatures has been improved while impeding the hardening of rubber compounds over time, thereby helping maintain the tyre’s performance.

The proprietary liquid rubber LFR uses farnesene manufactured from sugar cane using fermentation technology. Its viscosity is much lower compared with current liquid isoprene rubber. When used as an additive in rubber compounds, it imparts high plasticity. In addition, it maintains excellent flexibility even at low temperatures and improves ice grip performance.

Due to its optimal molecular weight, LFR reacts completely with solid rubber during vulcanisation, meaning, unlike oil, which would migrate to the rubber’s surface over time and thus impede hardening, it stays bonded. Therefore, its ice grip performance is maintained over the long term.

LFR possesses a highly branched brush-like structure with molecular chains that do not easily become entangled with one another. In addition, a highly reactive double bond on the end of each branch ensures that, when vulcanised, LFR completely reacts with solid rubber and solidifies.