Sustainable and silent
ITALY’S leading manufacturer of electric two-wheelers has specified the use of Thermolast® K for two precision gasketing applications on the new battery boxes of a growing range of power-assisted bikes and electro-scooters.
Askoll, based in Dueville (Vicenza, Italy) is using the thermoplastic elastomer material from Kraiburg TPE for an anti-rattle overmoulding of the battery connector and for water-tight sealing of the battery box. Key requirements to be met included reliable direct adhesion to glass-filled PBT on small contact surfaces.
Electric vehicles need innovative materials that will support their pleasantly silent travel by eliminating undesired ambient noises and – in the case of external components such as battery boxes on two-wheelers – ensure a weatherable and water-tight enclosure. This is opening attractive new application opportunities for thermoplastic elastomers (TPE).
“For the anti-rattle cover of the battery connector and the sealing of the redesigned battery box on our bikes and scooters, we were looking for a material that would provide the right balance of gasketing, mechanical and moulding performance,” explains Paolo Trabuio, project manager scooter, for Askoll. “Kraiburg TPE went a long way in supporting our efforts from concept to market, with qualified assistance in material selection, design optimisation, adhesion testing and moulding trials.”
Both TPE applications are injection molded in a two-component process, which required excellent direct adhesion to the glass-filled polybutylene terephthalate (PBT) resin used for the battery box. In addition, the chosen Thermolast K compound also had to offer good flowability to ensure a precise, tight and faultless fit of the gasket on the narrow contact surface of the lower box component. The compound also lends the critical long-life mechanical properties required to withstand the shocks and vibration of the box when driving, as well as the wear and tear during frequent removal for charging the maintenance-free battery on the electric grid at home or at work.