How Is Natural and Synthetic Rubber Made?

How Is Natural and Synthetic Rubber Made?

Natural rubber, originating from latex, is found in many manufactured products across the world. However, the majority of rubber used in the manufacturing process is actually synthetic. According to the European Rubber Chemicals Association, 32 million metric tons of rubber are produced every year, with 75% being synthetic.

This article will explore how rubber is made through both natural and synthetic rubber production methods.

How is natural rubber made?

Making a product out of natural rubber requires multiple steps, from the initial collection of latex through to heating the rubber to develop the lasting properties that make it so useful across a range of applications.

Step 1: Rubber Tapping

Firstly, a process called ‘rubber tapping’ occurs to collect liquid tree sap, latex, from plants. The majority of latex comes from the latex tree itself, named Hevea brasiliensis. The latex is then filtered before washing and reacting with acid to effectively coagulate the rubber particles. The rubber is then pressed and dried ready for the rest of the production process.

Step 2: Mastication, Chemical Addition, Calendering & Extrusion

The baled rubber is added into a mixing machine that masticates and warms it, which makes it easier to work, before being combined with additional fillers and chemicals. These are added to improve properties found in rubber, such as resilience and hardness.

After mixing, the raw rubber can be processed into different ways depending on the way the rubber will be used:

  • Calendering using rollers to produce flat sheets or rolls
  • Extruded into various sections/tubes and cut into sheets/shapes used in further processing

Step 3: Vulcanisation

In the final step of the rubber production process, the rubber is pressurised usually by moulding or autoclaving at a high temperature. This results in rubber with higher tensile strength and resilience against abrasion, alongside its elastic properties remaining effective over a wider range of temperatures.

How is synthetic rubber made?

Synthetic rubber production goes through similar stages to that of natural rubber. However, most synthetic rubbers begin with the creation of a hydrocarbon mixture made from oil or coal.

Naphtha, a liquid hydrocarbon mixture with flammable properties, is combined with natural gases to produce monomers – which create polymers by binding molecules together before the addition of chemical agents to create polymer chains which form a rubber substance. Once processed the bailed synthetic material can be processed in a similar way to natural rubber.

The advantage of synthetic rubbers is their ability to be tailored to enhance certain properties such as chemical, temperature, abrasion and texture.

Hopefully this article has answered all of your questions around how rubber is made. At Checkmate, we offer a complete service from conception to manufacture, and utilise a range of techniques to deliver our products. We’re always happy to chat, so contact us today to see how we can support your specialist engineering needs.