About seventy percent of the rubber used in the world today is a synthetically created rubber, as opposed to natural rubber which comes from latex sap from specific trees. The world now produces over 22 billion tons of synthetic rubber each year, which is made on rubber processing equipment from a polymerized petroleum base.
The creation of synthetic rubber was fueled by two major events in human history that required more than natural rubber could provide. The first is the rise of the automobile, which needed stronger, more durable rubber for tires that could resist temperature changes. The second was World War I when armies needed large supplies of rubber for hoses, gaskets, tires, and belts for war machinery as well as equipment like boots and clothing for soldiers. These events fueled research and development of many of the rubbers that we still use today.
What’s the process for making synthetic rubber?
First a petroleum liquid called butadiene is mixed with a solvent and boiled to remove any water. Once the butadiene and solvent are purified they are mixed with a specific catalyst depending on the type of rubber desired. This causes a reaction, turning the mix into a kind of synthetic liquid rubber. Another catalyst is added to stop the reaction at the desired time, and additional chemicals are then added to modify the rubber to its specific end use.
This liquid is then sent to a large tank along with a solvent and water, and is brought to a boil. As the solvent boils off, the rubber coagulates into small crumbs within the water. This water and rubber crumb mix is cooled and sent along a dewatering screen to remove the water and leave only the rubber crumb. The remaining crumb is then sent through a vibrating dryer, which is able to thoroughly dry the rubber crumb without the sticky rubber clumping together.
These dry crumbs of rubber are then compressed into large blocks, where they can then be sent off to a manufacturer for them to create into a final product.