BIW Isolierstoffe GmbH

We are the world market leader in silicone processing and cable protection systems.

BIW Isolierstoffe GmbH specializes in silicone processing and also plays a pioneering role in cable protection systems. The company is the world market leader in both sectors. The company’s technological market leadership can be attributed in part to the unique combination of silicone with technical textiles, especially glass silk. BIW processes 4,500 tons of silicone annually and realizes a variety of up to 175,000 different articles, which can also be reordered at short notice.

Today, the company develops and manufactures molded functional elements, seals, fabric-reinforced hoses and profiles for medical technology, the pharmaceutical industry and aviation. BIW is represented in the new Airbus aircraft generation as well as in modern dialysis machines. BIW also manufactures 60 million meters of customer-specific cable protection systems per year, which are primarily used in the automotive industry and in energy and electrical engineering.

The family-owned company, which is certified to ISO standards 9001, 16949, 13485, 14001 and 50001, sees itself as a partner and problem solver for its more than 5,000 customers. BIW is the only European manufacturer in the silicon sector to maintain its own technology center. Here, prototypes and proprietary silicone compounds can be created and qualified according to customer requirements. On average, 5% of annual sales are invested in research and development.

The company was founded in 1971 by Werner Stoffels and Gerd Oberhoff in Schwelm. As early as 1975, they succeeded in combining silicone and glass silk. In 1986, BIW moved production to Ennepetal-Oelkinghausen and grew continuously there. In 1990, son Ralf Stoffels took over the management of the company together with Dr. Markus Wiethoff. At the beginning of 2017, the generation change from the 2nd to the 3rd generation was completed in the family business. Today, BIW employs around 600 people and generates annual sales of 91,5 million euros worldwide.


Silicone processing and cable protection systems




World wide: 600

Sales Volume

2022: 91,5 Mio. €



New foundation of the BIW


Relocation to the industrial area of Oelkinghausen


Opening of technology center


Expansion of the production facility in Ennepetal


Foundation BIW China, Kunshan


Foundation of BIW Polska, Wroclaw


Generation change from 2nd to 3rd generation


Expansion of the Ennepetal production site by a further 12,000 m2


Pioneer in switching to chlorine-free production


BIW Isolierstoffe GmbH
Pregelstraße 5

Phone +49 2333 8308-0

World Market Leaders from A-Z