Turkish bus manufacturer Otokar utilizes a lightweight melamine resin foam from BASF as a sound absorber in the engine compartment for its bus models. To design and produce the various acoustic parts, the company partners with Teknofoam (Istanbul), the Turkish converting facility of Recticel (Brussels, Belgium).
Teknofoam selected, Basotect G flame-retardant open-cell foam achieves high sound absorption figures in the medium and high frequency range. In order to achieve good sound insulation over the whole frequency range, Teknofoam covers Basotect with a specially designed polyurethane film. This film and an additional nonwoven fabric layer also protect the foam from water and oil.
|Melamine foam sound insulation components are lighter than glass or mineral wool competing materials.|
Zafer Dogruyol, Purchasing Manager at Otokar, describes another advantage of the BASF foam: "The Basotect-based solution by Teknofoam is lighter than glass or mineral wool, which has been the common insulation material in recent years. The lower weight leads to a reduction in fuel consumption and CO2emissions. In addition, Basotect meets all European standards for noise insulation and fire safety. This is particularly important for Otokar because we also export our buses."
Heat resistance is crucial for any foam used in bus engine compartments. With diesel engines producing up to 213 kilowatts, temperatures of around 120°C occur regularly. Basotect offers long-term resistance to these high temperatures. In addition to specific requirements for acoustics and heat resistance, the various parts had to be designed and shaped according to the position of the engine, the cooling system or the exhaust system. "Using our computer controlled cutting, sawing and milling techniques, we could configure Basotect to the precise size and 2D or 3D shape. By providing the right pre-cut pieces according to CAD drawings, we also helped Otokar to reduce its installation time," explained Murat Hapci, Deputy General Manager of Teknofoam.
Basotect foam has a unique range of properties. Its base material makes it flame-retardant and abrasive; it can be used at up to 240°C and retains its properties over a wide temperature range. Because of its open-cell foam structure, it is light, sound-absorbing, and flexible even at low temperatures and thermally insulating.
As well as buses for city and intercity transport, Otokar manufactures comfortable buses for tourism and long-distance travel, where quietness in the passenger compartment is of particular importance.