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AUG 2018

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7 CompositesWorld.com Backing plates for brake pads also could benefit from being produced from phenolic composites. ese materials are regularly used in disk brake pistons —1.2 billion of which have been manu- factured since 1978. Current backing plates are made from steel, to which the friction material is bonded. Sumitomo Bakelite Co. Ltd. has shown that by using phenolic composites rather than steel for these parts, their weight can be reduced by as much as 70% — a significant savings, given that there are eight backing plates on each vehicle. Further, the friction material can be overmolded, so production is simplified, and the bond strength between the pad and the plate can be increased. Further, the inherent vibration- damping properties of the material eliminates the need for shims between the plate and the piston in conventional constructions. Perhaps most importantly, composite backing plates are inher- ently corrosion resistant. is is a boon for any vehicle, but will be of particular significance for PHEVs and EVs. In these vehicles, the regenerative braking system plays an important role in decel- eration, meaning that the friction brakes are used much less frequently. Indeed, they are equipped with only 5 mm of friction material rather than the conventional 10 mm. When they are fitted with metal backing plates, corrosion renders the PHEV and EV brakes unroadworthy before the friction materials wear through. e use of composites eliminates this problem, optimizing their service life. Although phenolics have been labeled by some as difficult because they can off-gas moisture during processing at elevated temperature, phenolic molding compounds today can be readily, reliably and efficiently transformed by injection molding, compres- sion molding and transfer molding. e surface quality of molded parts is more than adequate for the applications I've described here. Phenolic and epoxy composites are already being used in induc- tion electric motors for Renault's electric vehicles and in rotor magnet fixation used in Internal Permanent Magnet E-motors for a carmaker in Asia — these parts have been in serial production for two years. Bakelite may be old technology, but the current balance of cost, processability and in-service performance its phenolic successors can deliver will be key in enabling the new economy. Reinforced Phenolics Hendrik De Keyser is chief innovation and technology officer for Vyncolit NV (Ghent, Belgium). A chemical engineer by training, he has logged more than 30 years in the advanced materials and composites sector, and has worked for Vyncolit NV since 1988, beginning as a marketing development manager, responsible for developing applications for phenolics in a variety of industries, and then was responsible for taking these solutions to the North American market. After the company was bought by Sumitomo Bakelite Co. Ltd. (Tokyo, Japan) in 2005, De Keyser returned to Europe to take his current position in January 2016.

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