Quiet, please!

Angela Weik’s Acoustic Pads are quietly revolutionizing the automotive industry.

The ideal acoustic solution for car manufacturers needs to be light, easy to handle and invisible after installation. Our Acoustic Pads meet all these requirements – and more. They were developed by textile engineer Angela Weik. Here she writes about the outstanding properties of her innovation, her development breakthrough and her own ideas pipeline.

Our Acoustic Pads provide decisive advantages. They are extremely light – compared to competitive products, that can be up to 20 percent lighter. An enormous gain. We achieve this by distributing very few fibres across a lot of air. The advantage is that when our material is compressed, it nestles perfectly into the installation space in the car. Wherever it has room, it expands again and absorbs noise. This enhances the acoustics inside the vehicle and also the thermal insulation. The fleece-fiber mixture can also be installed invisibly in the vehicle, on the inside of doors and trunk walls, in the roof lining, in the A, B and C pillars and the wheel arch liners. So with our material, we are able to kill several birds with one stone.

The e-mobility challenge

This development is particularly interesting for e-mobility. Because alternative drives are much quieter than combustion engines, noises such as the rolling of the tires or the airstream are much more noticeable. On top of that, electric cars no longer have an engine that heats itself in winter. This makes it all the more important to install material in the vehicle that not only absorbs noise, but also has minimal weight and functions well as a heat insulator. As a result, the battery consumes less power and that in turn extends the vehicle’s range. Building up this acoustic expertise for the automotive sector in our company was a fascinating process.

Here’s how it works

Back in 2016, I began experimenting with nonwovens and padding materials with which we were already achieving good results in other areas. I used ultra-fine nonwovens from Freudenberg Filtration Technologies to achieve the highest possible flow resistance at the lowest possible weight. I also used padding from my Apparel colleagues at Freudenberg Performance Materials so I could create thickness without sacrificing lightness. Everything was focused on the two most important acoustic parameters: flow resistance and the distance to the wall.

It took a while, sure, and I kept having to start from scratch, but at some point I was really able to say for sure: Hey – that’s how it works! What’s special about our concept is that our AcousticPads absorb the sound and convert it into thermal energy. This has the effect of reducing the noise level of the car both to the outside and to the inside. In actual fact, the sample material that we produced and gave to a customer for testing immediately met with very positive feedback. Our material was much lighter than that of the competition while still producing optimal results. That was the breakthrough, our eureka moment, so to speak. We then continued developing the product with the customer and, in January 2020, the first vehicle with our new product came off the production line. We are very proud of that.

Available worldwide

Of course, it all sounds wonderfully simple at first glance. In reality, it takes a long time to get from the laboratory sample to the final product that will be produced in a large plant. Processes have to be constantly optimized to such an extent that the material can be produced at realistic prices while still achieving good results. That’s what we have achieved. We have succeeded in incorporating our lamination technique into the existing production process of our plants. This represents a huge success and is also a great advantage for our customers at the same time. This is because we have plants all over the world that can produce these paddings, meaning that the material is readily available worldwide.

The ideas pipeline

What will the future bring? Our next idea is to replace the ultra-fine nonwovens with a microporous foam so as to further optimize the flow characteristics. Foam is not delivered in a fixed width from a plant, but can be used variably. This gives us more flexibility. It means that would be able to respond even more individually to customer wishes, conserve resources and always supply our customers with exactly the quantity of material they need for their particular application.

We are currently conducting extremely rigorous tests to determine what results we will achieve if we add fillers to the foam. Will the acoustics in the vehicle be further improved? What about the thermal insulation? Can we be sure that the material will not release any substances in the long term that you wouldn’t want in the vehicle? So far, the foam has shown very good results. That’s exciting. We will keep working on it.