New polycarbonate roof is Smart addition to vehicle
A heat-absorbing panorama roof made of shatterproof polycarbonate has been added to the latest edition of Smart’s ‘fortwo’ vehicle to form an extended windscreen.
The roof system, made with Makrolon polycarbonate from Bayer MaterialScience, is the world’s largest injection-moulded, transparently coated car roof with an infrared absorber.
The new roof is designed to bring more light into the interior of the vehicle, enhance the driving experience through temperature regulation as well as reducing weight compared to glass.
Manufactured by Munich-based automotive supplier, Webasto, the technical highlight of the roof system is said to be its ability to absorb solar energy and prevent the interior from becoming too hot. This is achieved using infrared absorbers integrated into the granules of the polycarbonate panels.
The infrared absorption, which prevents infrared rays from entering the vehicle, also leads to reduced fuel consumption, says Bayer, as there is less need to use the air conditioning system to regulate the interior temperature.
The Makrolon AG2677 material is extremely impact-resistant, weatherproof and lightweight, with a roof made of polycarbonate can be up to 50 percent lighter than a glass equivalent, says Bayer. The plastic panel on the new Smart fortwo weighs 9.8 kilograms, which both reduces fuel consumption due to the low weight and also influences the car’s driving dynamics, as it shifts the vehicle’s center of gravity further down.
The roof is manufactured by means of two-component injection-compression moulding. Besides the transparent Makrolon AG2677, Bayer’s black-coloured polycarbonate ABS blend, Bayblend T95 MF, is used as the second component. This, says Bayer, enables the integration of additional functions such as screw bosses on the bottom side of the roof. Attached to them is an adjustable fabric roller blind used to control the brightness of the interior. A coating layer makes the panorama roof resistant to scratching and weathering influences.