ExxonMobil, Yokohama announce innerliner material

Houston, Texas -ExxonMobil Chemical Co. and The Yokohama Rubber Co., Ltd. (YRC) have jointly announced a new material for tyre inner liners, described jointly as a milestone. The material is specifically designed for  use in passenger vehicle tyres in harsh winter conditions.

The companies' development of DVA (dynamically vulcanised alloy) advanced tyre inner liner technology is based on proprietary Exxpro polymers and alloys of those polymers developed by ExxonMobil, 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, said the companies.

Satisfying low-temperature fatigue-resistance requirements is difficult for conventional inner liners. Tyres made with the jointly developed DVA advanced inner liners 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 material offer weight reduction of approximately 5.5 percent or 500g per tyre, and reductions in rolling resistance. These results are due to the exceptional air-retention properties of the DVA, which can 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.

ExxonMobil Chemical expects to commercialise a DVA resin product in the latter half of 2007. ExxonMobil Chemical is a major supplier of halobutyl rubber to the global tyre industry.