Air filters for optimum engine performance and clean air in the passenger compartment


For full power in internal combustion engines, an optimal fuel-air mixture is required. Just like the fuel, the air intake must also be clean. Dust particles, leaf mould and insects, once sucked in, harm the engine. In the worst case, they threaten engine damage, if they reach the combustion chamber. The regularly changed air filter effectively keeps all contamination away from the engine.

But the filter mount must also be tightly sealed so that nothing gets past the filter. This is what the SONDERHOFF foam sealing systems based on polyurethane and silicone do – also suitable for the foaming of filter end-caps. 

SONDERHOFF FERMADUR polyurethane seal adhesive systems are available for perfect bonding of filter packets.

To avoid such damage as this, regularly-changed air filters are built into the engine compartment, which count as some of the essential components of an internal combustion engine. These are responsible for keeping all intake air contamination away from the engine. This process is vital for faultless combustion and is absolutely essential if engine damage is to be avoided. The engine air filter has, among others, the following functions with regard to air management in the vehicle:

  • Filtration of engine intake air

  • Improvement of air flow for optimal combustion and engine noise reduction

  • Protection of downstream engine parts


SONDERHOFF seals fulfil high impermeability requirements

Dust particles, leaf mould and insects, once sucked in, harm the engine. If they get into the combustion chamber they threaten engine damage.

So that this does not happen, the filter must be firmly sealed into the filter frame, so that nothing gets past the filter and into the engine. Temperature-resistant SONDERHOFF FERMASIL silicone foam seals ensure this.

For the perfect bonding of filter packets, SONDERHOFF FERMADUR polyurethane seal adhesive systems are available.

The filters for fresh air intake in cars are sealed with SONDERHOFF FERMAPOR K31 polyurethane foam seals. They ensure a leak-free fit of the filter on the air intake passage, so that no unfiltered air passes the filter into the interior.

Special properties for special requirements


In order to keep the air in the passenger compartment free from VOC (Volatile Organic Compound) emissions, SONDERHOFF FERMAPOR K31 Low-Emission foam seals are often used for the tight sealing of filter housings in the car. They comply with the strict limit requirements of nearly all automobile manufacturers. The low-emission sealings fulfil, for example, Daimler’s in-house specification DBL 5452-13. This specifies as targets for VOC emissions 100 µg, and for fogging behaviour 250 µg per gram of polyurethane. The misting of the windscreen or the inside of the headlamps is avoided by the employment of low emission foam seals.

The features of SONDERHOFF FERMAPOR K31 foam sealings with antimicrobial sealing properties prevent micro-organisms and molds contaminating the seals of air filters used for air conditioning systems or climate control in cars.