Solid rubber, either based on natural rubber or synthetic polymers, appears as a hard product, difficult to compress, such as tyres or conveyor belts, for example. Foam or sponge rubber, on the other hand, is produced by adding a foaming agent to the compound. These agents produce gases that expands during the manufacturing process generating air bubbles (cells) inside the material’s structure. Consequently, foam rubber appears as a soft and light material, easily compressible, ideally suited for the production of seals and gaskets.