A rubber compound is obtained by mixing a base polymer or crude mixture with a series of additives. The choice of the base polymer and the additives is closely linked to the type of properties to be achieved. The resulting product is a non vulcanized compound. The quantity of additives used varies for 20 to 130% as a percentage on the weight. The most common additives are:
There are two types of fillers, reinforcing and non reinforcing fillers. Carbon black is commonly used as a reinforcing filler. This is also the reason why most rubbers are black. Calcium carbonate is an example of a non reinforcing filler.