Rubber begins to melt at approximately 180 degrees Celsius. At low temperatures, around 5 C to 6 C, there is a risk that rubber hardens because of crystallization. The optimum temperature for rubber is 20 C.
Natural rubber is made from plant material. The tree Hevea brasiliensis secretes a milky substance called latex, which is used to produce rubber. Among the many uses of rubber is for the manufacturing of tires, footwear and gloves. These items are made either by casting latex or immersing a mold into it. Waste rubber can be reclaimed through a process that includes grinding the used rubber and using chemicals for devulcanization.