Sound absorption, noise, vibration and harshness (NVH) control

Sound Absorption

“One day man will have to fight noise like cholera or pestilence” (Robert Koch). Bayfit® takes on this challenge. Noise makes you ill and tired.

Sound Absorption Kundt's Tube
Sound Absorption Kundt's Tube (larger version see below)

If a driver is exposed over a long period to a loud engine and driving noise, it is not only bad for his or her health, it also constitutes a significant safety risk. Covestro tackles the problems of air-borne and solid-borne noise with sound-absorbing polyurethane systems to create more pleasant interior acoustics. The ideal solution here is to use Bayfit® polyurethane foams or Bayflex® polyurethane heavy-layer cladding, either alone or in combination. Ideally – also from the environmental point of view – the component will be made entirely of polyurethane. It will convince even the most critical of acoustic specialists.

In fact, Bayfit® noise killers form the sound insulation on the bulkhead behind the dashboard, or the foam backing on carpets and wheel arch shells or they disappear in modules for the engine compartment insulation. With their optimized foam structure and perfect cavity filling, Bayfit® foams offer excellent absorption of air-borne noise. The viscoelastic grades in combination with a heavy-duty layer of Bayflex® SA also results in ideal solid-borne sound and vibration damping. This is used a lot in cars and trucks but not limited to this application.

With the highly filled Bayflex® systems for heavy layers, there is also a choice between two methods of processing. The classic RIM process can be used. With state-of-the-art machinery the spray process – in the form of Bayflex® SP gives maximum process flexibility. With both methods, the layer thickness can be varied at every single point on the part as instructed by the acoustic expert.

All products can be processed very economically as moldings with low scrap rates because no time-consuming cutting-to-size is needed. They can also be adjusted to the most complex part geometries and spare the ears – and nerves – of driver, passengers and the environment.

Bayfit® molded foam can be molded inside the pillars of the car to stop spreading the noise. Bayfit® molded foam can be used on the engine, too. This is not only good for the people inside the car or the truck but all people that suffer outside.


The advantages of Bayfit® for sound insulation:

  • Sound absorption of air-borne noise
  • Dampening of solid borne noise as component in mass-spring damper systems
  • Good long-term service properties under high mechanical stresses and extreme climatic influences
  • Elastic, viscoelastic and adhesive grades possible
  • Compliance with the typical emissions and odor specifications
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