It all started with leather mordant

Darmstadt is the long-established site of Evonik Industries for polymers chemistry and especially the development and production of Plexiglas. This industrial site, however, has its roots in something quite different, namely leather mordant. The location was originally founded by Röhm & Haas, a predecessor company of Röhm GmbH, which was originally located in Esslingen on the Neckar.

It was there in 1907 that chemist Dr. Otto Röhm discovered a method of biting leather using enzymes from animal stomach salivary glands. He went on to develop the product OROPON®. After a difficult market introduction, some progressive leather factories switched from the unhygienic, but at that time customary dog-excrement mordant to Otto Röhm's new leather mordant. Demand grew rapidly, with Esslingen production reaching capacity after only two years. Otto Röhm finally found and acquired a conveniently situated site with room for expansion for new production and established today's Evonik site. The area's advantage for Röhm was that the big leather factories in Offenbach, Weinheim and Worms were all located nearby. The former royal capital and garrison town of Darmstadt had created this industrial site in the early 20th century with a view to opening up to modern industrialization.

From Darmstadt all over the world

On July 22, 1909, Röhm & Haas moved to Weiterstädter Straße in Darmstadt. The buildings already in place enabled work to start in August. The 5,800 m2 site covered the initial space requirement and the extensive as yet undeveloped adjacent sites allowed the plants to be expanded at a later date.


Darmstadt plant, 1909

Only a year later, however, the production capacities calculated by Otto Röhm proved to have been underestimated. As a result the first business expansion took place in 1910 and by 1911 a new two-story factory had been completed. This was the start of a facility expansion program lasting many years. Röhm's plans to shape the plants into a uniform entity as part of a major construction project were dashed though by the outbreak of the First World War. The difficult post-war years meant that for a long time expansion was only possible in individual phases.

The larger space available in Darmstadt enabled Röhm to work on other interesting applications for enzymatic products. This led in 1914 to the introduction of new products in the leather and textile industry as well as laundry washing. In 1916/1917 an office building, a laboratory and a leather technical center were extended in several construction phases up to the Kirschenallee. The resulting corner building, which housed the main entrance for many years and was seriously damaged in the Second World War, is now a listed building.

Boom time thanks to PLEXIGLAS

Pharmaceutical products were also manufactured from 1919/1920. This new division required repeated extensions to the plants. Finally in 1921 Otto Röhm set up an experimental facility for acrylic compounds, since the research department recognized the development possibilities of this branch of work. The first saleable acrylic polymers were produced in 1928, followed in 1933 by great success following the invention of acrylic glass, which Röhm patented under the trade name PLEXIGLAS®.

Further new developments in this methacrylate field were launched on the market from 1935. This triggered further expansion. From 1909 to 1921 some 37,000 m2 of construction and agricultural sites were acquired, and 1933 saw the beginning of a 10-year ongoing program of property purchase aimed at expansion into a coherent company site. By 1943 the Darmstadt facility covered a total area of 103,000 m2. Production and sales department expansion was principally due to the increased armament efforts of the National Socialists after 1933: Röhm's PLEXIGLAS® product was needed in the construction of aircraft cockpits.

It was already recognized in the 30s that there were limits to the rapid and continued production expansion in Darmstadt. Consequently a 270,000 m2 site was purchased in 1938 in Mittenwalde near Berlin with a view to installing additional PLEXIGLAS® production capacity.

Strategic military considerations also played a part in production decentralization. The Mittenwalde facility was occupied by the Red Army in 1945 and later expropriated into the Soviet-occupied zone.

Both the enzyme and acrylate/methacrylate business areas had launched a large product range. In addition to the ongoing construction and expansion programs, the number of permanent staff in Darmstadt also increased rapidly. The business began with eight people in 1909, and was already recruiting its 1,000th employee in 1937. In 1943 the workforce had grown to 2,975.


Darmstadt plant, 2000

In order to cover the growing staff requirement, an increasing amount of allocated forced labor was used. Production was running at full speed, until the factory was reduced to rubble during an air raid in September 1944. After further minor attacks 80 percent of the plants were eventually destroyed.

Fresh start after 1945

As early resumption of production was not in the cards; after the occupation of Darmstadt on March 25, 1945, extensive staff cuts were made, leaving only 527 factory employees. However, after Otto Röhm, son of the company's founder, joined management, reconstruction started in May 1945. Management and staff helped to dig machinery out of the rubble, break stones and build walls. People were gripped by the enormous desire to rebuild. However many of the machines that still remained were dismantled. Only monomer production was spared from attack and rescued before dismantling took place. It formed the cornerstone of methacrylate production, though dismantling operations continued until 1949.

After the war Röhm & Haas initially survived on residual sales of PLEXIGLAS® and pearl polymers for dental plates, which were produced in a makeshift facility. Tanning and textile auxiliary products and detergents were produced again on a modest scale from 1946. Small-scale production of PLEXIGLAS® started in 1947. The upturn began in 1950, partly as a result of currency reform, leading to increased orders, which in turn resulted in greater production expansion and further staff recruitment. By 1952 the company already employed over 1,000 people. In some cases product demand rose so sharply that investment could not keep pace. Customers often had to accept delays or piecemeal deliveries of their orders. The Darmstadt factory was a typical example of the German economic miracle.

In Darmstadt the production of all available Röhm & Haas products was developed and expanded, and some new products were added, such as PLEXIDUR®, VISCOPLEX®, EUDRAGIT®, and later ROHACELL®. However, this meant that the site quickly reached capacity and a larger site had to be acquired in addition on the outskirts of Darmstadt, where a new factory was built. From 1968 this Weiterstadt factory initially provided sufficient space for the production and storage of PLEXIGLAS®. Even so the Darmstadt workforce also increased, reaching 2,882 by 1990.

Röhm becomes subsidiary

The takeover of Röhm GmbH by Hüls AG in 1989 led to reorganization, and permanent staff numbers were cut to around 1,500. When Hüls AG and Degussa merged to become Degussa-Hüls AG and amalgamated with SKW Trostberg AG, the former Röhm GmbH finally became part of the Degussa Group which then became Evonik Industries in 2007. Within Evonik, the Darmstadt site today plays an important role in research and application technology as well as in the manufacture of products such as ROHACELL®, VISCOPLEX®, EUDRAGIT® and DEGALAN®.