Historical image of sheets, blocks and tubes made of PLEXIGLAS®

©Evonik Industries AG, Konzernarchiv Hanau

From sheet to tubes and rods

The story of PLEXIGLAS® began in 1933 with thin acrylic glass panels. Shortly afterwards, blocks, tubes and rods could be produced from the new material.

Even as the company Röhm & Haas, a predecessor company of Röhm, was registering PLEXIGLAS® as a brand in 1933, the research department was already puzzling over how to improve the manufacturing process and increase the product quality. They developed, among other things, a production process according to which PLEXIGLAS® sheets are still cast today. But that was only the start of a rapid development of application research.

Sheets, blocks, tubes

Otto Röhm and his colleagues were fascinated by the fact that they had developed an organic glass substitute. Initially, the researchers concentrated on applications where the focus was on the much lighter weight compared to silicate glass. Thus the first small sheets of PLEXIGLAS® were initially used for protective goggles, gas masks and watches. But curiosity quickly prompted Otto Röhm and his colleagues to expand their research to find other applications for PLEXIGLAS®: The chemists of the organic-synthetic department tried everything they could think of; experimenting with sheet thicknesses and processing methods.

Block of PLEXIGLAS® from 1938

Thicknesses up to 50 mm

Soon, thicknesses of 1 mm to blocks of up to 50 mm were produced. The production of blocks began between 1934 and 1935, initially in a soap press, but later in a specially designed horizontal press.

© Evonik Industries AG, Konzernarchiv Hanau

Cutting, drilling and milling PLEXIGLAS®

It soon became apparent that the acrylic glass could be cut, drilled and milled in different thicknesses. In addition, the finished sheets were moldable at high temperatures below their melting point – a property which represented a huge difference compared to the thermosetting plastics available at that time, the shape of which cannot be changed after the first cooling down. This made PLEXIGLAS® a sought-after material in aircraft and vehicle construction,  in which curved panels made from the innovative plastic have helped to achieve previously unforeseen speeds.

Crystal-clear transparency

Even the transparency of today’s brand acrylic glass from Röhm dates back to a discovery from the early years: The chemists found a way to manufacture PLEXIGLAS® without a plasticizer – which gave the material its crystal-clear transparency that it’s known for today.

Greater application versatility

Shortly thereafter, Röhm & Haas were no longer just producing sheets and blocks, but also the first tubes, using a centrifugal casting process. This involves polymerization – the chemical process by which PLEXIGLAS® is produced – being carried out in rotating molds. The development of the molding compounds, an acrylic glass granulate for injection molding which today bears the brand name PLEXIGLAS® Molding Compounds, began in 1935 as well.

From invention to household product

The material became widely known through concerts with instruments made of PLEXIGLAS® shown on the Ufa-Wochenschau newsreels and broadcast on the radio. By 1936, the new material could be found in many households, thanks to the production of salad servers, household goods and jewelry. PLEXIGLAS® also became popular abroad after being awarded a Grand Prix and a gold medal at the International Exposition of Art and Technology in Modern Life in Paris in 1937. Today Röhm’s brand acrylic glass is one of the best known plastic brands in the world and it is a sought-after material for architecture, technology, design and shopfitting.