Silicone Playing a Big Role in Automotive Safety

As the number of cars and trucks around the world rises from 750 million to an estimated 1.1 billion by 2020, drivers and passengers will rely on increasingly sophisticated systems not only to protect them in the event of an accident, but to avoid them altogether.

Thanks to safety-focused designers and enabling materials such as silicone, automobiles safety features are no longer the stuff of science fiction. Drivers soon will be assisted by technology designed to help predict and prevent accidents, alert drivers to imminent danger, and even intervene if the driver fails to react. In the event of a collision, drivers and passengers will be protected by smart air bags that can measure the severity of an impact and deploy at a commensurate speed and force, as well as impact-resistant and ultra-absorbent interior materials used between the body structure and the interior trim.

Industry experts are hopeful that such improvements can go a long way toward reducing the 1.2 million deaths each year that World Health Organization estimates come from traffic related injuries.

"Safety was not a big selling point for new cars until the mid- to late- 1980s, but it certainly is now and designers and engineers are responding accordingly," said Randall Rozin, Dow Corning Automotive Industry leader. "Materials and technologies unheard of a generation ago are making automobiles the safest and most reliable they've ever been."

Because innovative systems, modules, and components must work under extreme loads, speeds, temperatures, and exposure to water and dust, designers and engineers are increasingly turning to silicones, which offer excellent thermal stability, mechanical and corrosive resistance, and good compatibility with metals, plastics and elastomers.

An estimated six to seven pounds of silicone materials are used in the typical car or truck, meeting challenges that range from mechanical to aesthetic. Silicones are commonly found in applications such as adhesives, insulating and sound-proofing materials, lubricants, protection materials, sealants and gasketing, and torque transfer fluids.

"Silicones are allowing automotive designers and engineers to explore new applications and improve on old ones," said Rozin. "Perhaps in no other industry does silicone technology have more potential to improve and protect lives."

Specific innovations include:

• Tires -- Today's tires offer much greater grip, particularly in wet conditions. Gaining popularity are so-called "green tires," which have improved grip and rolling resistance as well as the added benefits of improved fuel economy and lower environmental impact. When adoption of green tires was low -- due to the cost of manufacturing the silica used to reinforce filler in tread compounds rather than traditional carbon black -- Dow Corning developed a method to produce silane (a type of silicone needed for the silica treatment component) in a more affordable way. This reduces the cost of producing green tires, which could lead to wider use.
• Electronics -- Electronic stability sensors can detect such things as tire slippage, obstacles on the road, and how fast the steering wheel is being turned in order to make decisions for the driver on traction control. For example, sensors can detect that tires are spinning on snow or ice and change the throttle pressure to compensate for what the driver is trying to do. Silicone coatings protect delicate electronic circuits used to control these sensors, as well as other electronic devices, against temperature extremes, moisture, salt spray, and other contaminants.
• Air bags -- Liquid silicone rubber is used to coat airbags, enabling even deployments and protecting the fabric from the heat and force of inflation. In addition, a new textile coating from Dow Corning allows side curtain airbags to remain inflated longer to improve protection in rollovers. It also allows them to be folded into a narrow area above a vehicle's door to make design and assembly easier. Silicone fluids are used in deployment sensors for their exceptional viscosity temperature stability.
• -- Brakes -- Once asbestos brake linings were no longer used in automobiles, corrosion problems resulted. In response, Dow Corning developed a friction-control additive to provide moisture protection and high-heat stability, which enhanced brake safety and performance.
• -- Lights -- Dark corners will be a thing of the past as high-performance lubricants allow a new generation of headlights to turn with the front wheels, illuminating the path around a corner. In addition, light emitting diodes (LEDs) using silicone lenses are providing performance and safety benefits to taillights that turn on instantly to give trailing drivers more time to stop, offer better visibility in poor weather, and last longer than incandescent bulbs.

"Designers and engineers around the world continue to turn to us for products and solutions that will add safety, dependability, comfort, and value to increasingly complex automobile components and systems," said Rozin.