In 1916, Straumann joined Thommens Uhrenfabrik, Waldenburg's prominent watch factory. Straumann rose to become technical director of the factory, which was managed by his cousin, Doctor Hermann Straumann from 1932.
Straumann studied materials science in his spare time, working in a laboratory in Waldenburg. In 1931, he collaborated with the German materials firm Heraeus to create a new hairspring material that would not change in elasticity due to changes in ambient temperature. The resulting material, an alloy of nickel, iron, and other metals, was particularly valuable in the production of hairsprings and balance wheels. Named Nivarox, it was resistant to fracture, corrosion, and magnetism and was perfected in 1933 and patented in 1935.
Straumann left Thommen in 1934 and founded Nivarox SA in Saint-Imier that year. The company would merge with Fabriques d'Assortiments Réunis (FAR) of Le Locle in 1984 and remains one of the most valuable components of the Swatch Group.
After the death of his father in law, Fritz Heid, Straumann became director of Tschudin + Heid AG, a watch component producer in Waldenburg. He continued working to create new materials in a laboratory there, and patented a new mainspring material, Nivaflex, in 1948. He founded another company in Saint-Imier to develop this material, Nivaflex SA, in 1948.
Straumann's Waldenburg research laboratory became Institute Dr. Ing. Reinhard Straumann in 1954, with research continuing on new materials. The institute focused on areas of interest to Straumann, chiefly ski flying, watch materials, and test equipment. The company would be renamed Straumann AG in 1990 and would focus on development of dental implants.