Expanding potential of fluorosilicone rubber

Dow Corning, a leading company in silicon-based technology, silcone and innovation, has launched a major new enhancement to its Silastic® Fluorosilicone Rubber (FSR) portfolio at the SAE 2015 World Congress. In this new technology, Dow Corning has integrated its know-how in developing, mixing and compounding with its ability to alter polymer structure, to create a highly heat-resistant Silastic FSR technology for extreme high-temperature applications.

This innovative technology will enable FSR-engineered elastomers manufactured by Dow Corning to match the requirements of customer automotive applications, which require durable and dependable operation at temperatures beyond 220°C.

The automotive industry worldwide invests significant resources to gain dramatic reductions in vehicle emissions. Materials must be specifically engineered to deliver high performance and meet increasing emission-control requirements. With automotive design moving towards smaller engine compartments, increased exhaust gas recirculation and decreased air flow, the high-end temperatures in underhood environments are climbing and, more importantly, driving the performance requirements for FSRs to extremes not previously required.

In collaboration with the automotive industry, Dow Corning has developed an innovative new technology platform for its Silastic FSR line that boosts temperature resistance for extended periods of time and offers expanded flexibility for next-generation automotive designs.

A special breed of material
FSRs belong to a special category of silicone polymers, which add increased chemical resistance to superior temperature performance characteristic of silicone technology. These materials can handle prolonged exposure to extreme automotive fluids, oils and fuels, and traditional grades function reliably at temperatures up to 200°C, thereby making them a common material solution for fuel systems, transmission seals and turbocharger hoses.

However, even using performance-enhancing additives do not help traditional FSR grades to meet the requirements of new automotive designs as these designs are progressively increasing underhood temperatures to new highs.

Being a leading manufacturer of FSRs has allowed Dow Corning to approach this challenge in a holistic manner by focusing on raw materials, polymer design, additives and processing so as to enhance complete material performance. This resulted in Dow Corning developing a novel FSR technology proposal capable of providing reliable, durable performance at higher temperatures.

To prove the capabilities of the newly enhanced FSR platform, the company performed a series of tests such as fluid exposure, long-term heat aging, and elevated mechanical testing and adhesion to high-consistency rubber (HCR). Dow Corning’s advanced FSR technology successfully passed these tests at temperatures exceeding 220°C for prolonged periods of time.

Based on the successful technology, Dow Corning can look at customising new cutting-edge FSR solutions to suit the accurate performance requirements of customer applications such as thinner wall sections, reduced systems cost, lower weight, easier processing, and improved stable performance over a wider temperature range than other traditional platforms.

Applications for which Silastic FSR characteristics and processing features can help provide performance improvements include turbocharger hose liners, engine and transmission seals, fuel and oil system seals, flexible diaphragms and valves.

For instance, more durable turbocharger hoses, fabricated with Silastic high-consistency silicone rubber (HCR) outer layers and FSR inner liners, can offer long-term resistance to peeling and delamination in harsh  operating conditions because of the added adhesion stability.

The Dow Corning’s improved Silastic FSR compounds are provided worldwide in ready-to-use rubber crepe mixtures designed for conventional moulding, calendering and extrusion methods.