Usually, what we call natural rubber refers to the natural rubber latex collected from rubber trees in Southeast Asia or Brazil, and is an elastic solid made by coagulation, drying and other processing procedures. Natural rubber is a natural polymer compound with polyisoprene as the main component. Its molecular formula is (C5H8)n. Its rubber hydrocarbon (polyisoprene) content is more than 90%, and it also contains a small amount of protein and fatty acid. , sugar and ash, etc.
Natural rubber can be divided into two categories according to the form: solid natural rubber (film and granular rubber) and concentrated latex. In daily use, solid natural rubber accounts for the vast majority of the proportion. Films can be divided into smoked flakes, air-dried films, white wrinkled films, brown wrinkled films, etc., according to different manufacturing processes and shapes. Among them, smoked flakes glue is the most representative variety of natural rubber, and it has always been used in large quantities and applied. A wide variety of rubber is generally graded according to its shape, and is divided into six grades: special grade, first grade, second grade, third grade, fourth grade, and fifth grade.
Because natural rubber has a series of physical and chemical properties, especially its excellent resilience, insulation, water resistance and plasticity, and, after proper treatment, it also has oil resistance, acid resistance, alkali resistance, heat resistance, cold resistance, pressure resistance , wear-resistant and other valuable properties, so it has a wide range of uses. At present, there are more than 70,000 items in the world that are partially or completely made of natural rubber.