ExxonMobil Chemical and Yokohama Rubber Develop Inner Liner

ExxonMobil Chemical Company and Yokohama Rubber Co., Ltd. (YRC) have developed DVA (dynamically vulcanised alloy) advanced tyre inner liner technology based on proprietary Exxpro polymers as well as alloys and application technology developed by YRC. The DVA advanced inner liner technology used in the film liner materials combines the flexibility and elasticity of a rubber with the low-air permeability of a plastic.

Tyres made with the jointly developed DVA advanced inner liners have now passed rigorous cold-temperature indoor tyre testing and outdoor road testing. Tests were conducted over a six-month period in northern Canada in temperatures reaching -22°C.

In addition to their cold-temperature toughness, 15-inch V-rated passenger car tyres using the DVA advanced inner liner have shown light-weighting gains of approximately 5.5 per cent or 0.5 kilograms per tyre, and reductions in rolling resistance. These results are due to the air-retention properties of the DVA, which are said to be 7-10 times better than those obtained from conventional 100 phr halogenated butyl rubber (halobutyl rubber) liner compounds.

In 2004, ExxonMobil Chemical and YRC announced a joint cooperative agreement and ExxonMobil’s acquisition of a global license from YRC for DVA inner liner technology.

In October 2005, ExxonMobil Chemical announced a multimillion-dollar investment to double production capabilities for its proprietary Exxpro™ specialty elastomer used in DVA advanced inner liner construction. The expansion of the company’s plant in Baytown, Texas, is targeted for completion in the fourth quarter of 2006.

ExxonMobil Chemical says it expects to commercialise a DVA resin product in the latter half of 2007.