Fibre-reinforced LSR offers stiffer vulcanisates

ERJ staff report (DS)

Friedrichshafen, Germany -- Momentive Performance Materials and the Woco-Group have jointly developed a family of fibre-reinforced liquid silicone rubber (LSR) materials. The companies say the new materials process like standard liquid silicone rubbers in terms of cure speed and flowability, but the modulus of the materials has been significantly increased through the use of textile fibers, chemically bonded to the silicone matrix.

“Woco has 3 decades of experience in automated LSR processing,” said Alexander Widmayr, Manager of Woco's Sharjah, UAE plant for LSR parts. “The idea for this development came when I realised how labour- intensive the process of textile reinforced membranes has become. After initial trials in our lab we decided to team up with a leading supplier of LSR to finalise this development and overcome the limits in our process. Together with Momentive Performance Materials, we worked to better understand the impact of fibre-material and geometry, as well as its chemistry. We have succeeded in prototyping parts with an impressive new performance window.”

Target markets for this new class of materials include applications where the silicone elastomer alone cannot withstand pressure, or where reinforcement is contributing to the safety of the part. This includes products such as membranes, pressure hoses and exhaust hangers. In addition to a significant potential cost reduction through high yield and less wasted material in the LSR process, considerable weight savings can also be achieved in certain applications.

“Our main targets for development are automotive and industrial applications”, explains Ralf Möller, leader of the CAE department of the Woco Group. “The development process took quite some time, to ensure that we can predict parts performance with this new material by means of non-linear finite element analysis, to minimize the risk of failure. We had to develop a new approach in suitable non-linear material laws to achieve this goal, and are now confident that we can support the focused new developments of complex parts.”

“Fiber-reinforced elastomers have been used in the industry for decades,” adds Oliver Franssen, Global marketing Manager for Elastomers Automotive of Momentive. “However, outside of the tire industry only little has been done in the area of automotive mass-production applications. Together with Woco, we have developed a new approach, where the fibers are bonded to the substrate, and where short cycle times in LSR injection molding can be achieved. Based on the heterogeneous fiber distribution in the low viscosity LSR, the development of complex reinforced parts with homogeneous material properties is now possible.”

The new materials are on show at the Fakuma fair in Friedrichshafen

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Press release from Momentive