Vulcanised Rubber

For thousands of years, latex (plant sap) has been harvested from the bark of various plants and used, in its dried form, as a flexible sealant — albeit with limited applications.

It wasn’t until 1839 that Charles Goodyear made a groundbreaking discovery: he accidentally dropped a piece of latex mixed with sulfur onto a hot frying pan, which caused the latex to solidify. Latex contains long molecular chains, and when sulfur is added, it forms cross-links between these chains. The combination of sulfur and heat triggered a chemical reaction, resulting in what we now refer to as vulcanised rubber — unlocking a vast new range of applications.

Originally, vulcanisation referred solely to the treatment of natural rubber with sulfur. However, with the development of synthetic rubber compounds and the need for more efficient vulcanisation methods, new chemical vulcanisation systems were introduced. Still, the core process remains the same: rubber is vulcanised when heat and pressure are applied during production. Pressure ensures that the rubber is compacted and pressed into the mould cavity — which determines the final shape of the component. The result is an elastic rubber product that returns to its original form once external forces are removed (for example, a bellows).

Fact box: The term “vulcanisation” is derived from Roman mythology, where Vulcan was the god of fire, volcanoes, and blacksmithing.

At Gravlund Industrigummi, we exclusively use rubber compounds from European suppliers to ensure consistent, high-quality vulcanised components.

We can truly call ourselves a rubber manufacturer, as we operate two mixing mills, enabling us to adapt the rubber compounds we receive from our suppliers to meet specific requirements.

The physical properties of rubber types are evaluated based on their resistance to the environmental conditions the final product will encounter. Each rubber type has unique characteristics, and within each type, there are many variations. We advise our clients on the most appropriate rubber compound for their specific application and, if necessary, collaborate with our network of technical experts to define a tailor-made formulation.

When designing a new rubber component, it can be difficult to communicate the desired hardness level. To help bridge this gap, we have produced a hardness indicator featuring six different Shore A hardness levels — from 30 to 80 — to give a tactile reference. Contact us at [email protected] to receive a free sample.