From Pyrotechnics to LSR - Wacker Chemie AG

From Pyrotechnics to LSR

The Dedicated LSR Website went online two years ago. Ever since, interesting articles on this subject have been available every month from So now it’s high time we spoke with a bona fide LSR expert – an expert like Berndt Stadelmann. The Ph.D. chemist has been working with silicone rubber for nearly 30 years now, making him something of a rubber guru …

Dr. Stadelmann, given your experience and expertise, it would be fair to refer to you as a rubber guru. So let’s ask the expert: What makes liquid silicone rubber so special?

He knows his way around silicone rubber and cannot imagine a more interesting field of work: Dr. Berndt Stadelmann, LSR/RTV product line manager in the Engineering Silicones business unit.

Well, there are definitely plenty of gurus in the field of liquid silicone rubber. And by that I mean that all of the development and success of this product line are built on a foundation of interdepartmental teamwork. In my current role, I’m involved more in commercial and global marketing, and serve as an interface to the supply chain. But getting back to your question – what makes LSR so special is its workability in LSR injection molding, along with the terrific final properties of silicones: thermal stability, pigmentability, short cycle times, and the ability to perform delicate molding operations.

Which LSR product would you say has the best chance on the market or the greatest potential for development and applications?

One of the potentially most powerful materials is definitely the group of self-adhesive liquid silicone rubber products, because they add interesting features when used as the soft component in combinations of hard and soft materials.

You’ve been working with LSR products for such a long time – which one generates the most market demand?

The self-adhesive materials I mentioned earlier have consistently been in demand for years, but demand for our classic, standard LSR is pretty common too, because it’s so versatile. Requests have recently been on the rise for highly transparent materials and for products with low levels of volatile organic compounds, or VOCs.

Quality plays a major role with LSR – what does that mean in terms of the manufacturing process?

Each LSR product is manufactured according to high standards of quality. SILPURAN® products are produced under cleanroom conditions, which complicates the manufacturing process somewhat.

Our readers are always interested in markets and trends. Most recently we discussed the latest developments in a live report from the SKZ Forum. What direction is current LSR research taking at WACKER?

Our main research priority right now is to add more transparent materials to the portfolio – we’re working on optimizing viscosities for injection molding, reducing volatility and improving adhesion to a variety of substrates.

Have you acquired any particularly interesting LSR memories over the course of your career?


Even at an early age, this native of Linz, Austria, showed a passion for chemistry and was excited about his junior chemistry set – and especially about its potential for pyrotechnics. After earning a degree in chemistry and writing his doctoral dissertation on the subject of “Alpha-Omega Transition-Metal-Substituted Linear Oligosilanes,” Stadelmann joined WACKER in 1997. Since that time his work in the Group has focused entirely on silicones – only the teams and locations have changed.

Yes, I remember trying to promote LSR during my time in Brazil. Once when we were visiting the production site of a major potential customer, we were asked if we could deliver our drums in wooden frames in order to prevent the drums from being dented during shipping. The customer showed us the dented samples and the drums from the competition – which were in various types of wooden frames. Because of the complexity, Burghausen wasn’t able to provide wooden packaging that quickly. Our former production manager at WACKER Brazil promised the customer we would only select undented drums from Burghausen and that we knew a carpentry shop where we could get some inexpensive wooden frames made for us. One afternoon as I was walking across the courtyard from the cafeteria, I saw what he’d meant by that: several people from Production were hammering and sawing away at home-made wooden frames – when it was 35°C in the shade. But then, service and a focus on the customer have always been really important at WACKER.

And the customer?

The customer was very satisfied, of course.

And speaking of satisfaction – what do you think of the idea of a dedicated LSR website like the one at

Great idea – just google it and you’re there!

Would you please complete this sentence? “In ten years, LSR will…

… be found in far more applications than it is today.”

Thank you for the interview.