How Rubber is Made?

How Rubber is Made?

Rubber is an essential raw material which is used in production of many products used in our everyday life. Rubbers are natural or synthetic materials characterized by elasticity, water resistance and electrical insulating properties, from which rubber is obtained by special processing. Today we will talk about the process of rubber production, how it is made and where it comes from.

Natural rubber

Natural rubber is made from a milky-white liquid called latex – the sap of certain types of rubber-producing plants, which can be found originally in South America and now in Southeast Asia. The first acquaintance of Europeans with natural rubber occurred five centuries ago, and in the United States, rubber goods became popular in the 1830s, rubber bottles and shoes made by South American Indians were sold in large quantities. The rubber production begins with the tapping process which means gathering the latex from rubber-producing trees by cutting the bark. Latex then is collected in the cup held around the tree trunk. In order to prevent the solidifying of the sap, latex is kept in metal pans using a dilute acid. This process is called coagulation and takes around 12 hours. After coagulation the white extracted mixture is rolled and washed to remove the water and acid. The resulting sheets of raw rubber are dried over wooden racks generally for several days.

Synthetic rubber

Recently, synthetic rubber has been used as a substitute for natural rubber in many cases. During the times of World War I German scientists created the artificial rubber in a laboratory. Synthetic rubber is made by polymerization (linking) of molecules. There are so many types of synthetic rubber which result from different polymerization methods.

Rubber Processing

Processing rubber goes through four important steps: compounding, mixing, shaping, and vulcanization. Different kinds of required chemicals and additives depending on the final product are added to the rubber during the compounding process. The most popular additive is black carbon filler, that is why most rubber products are black. The black carbon filler improves rubber’s resistance to abrasion and tearing, and strength. Originally discovered in 1839 by Charles Goodyear, vulcanization completes the rubber manufacturing process. It is a heat-treatment phase which makes the rubber strong and durable. Usually, sulfur combined with other chemicals is used in this process, and the mixture is cooked for about 15-20 minutes.