About 2000 kinds of plants can produce polymer similar to natural rubber in the world. Rubbers of different categories have been obtained from 500 kinds of plants. However, it is the para rubber tree that actually has practical value.

After making incision on the surface of a rubber tree, the latex tube in the bark is cut off and latex flow out from the tree. The latex collected from the trees will be diluted, added with acid for solidification and washed. Then, after tabletting, drying and packing, the natural rubber commercially available is fabricated. According to different methods of rubber fabrication, natural rubber can be fabricated as smoked sheet, air-dried rubber sheet, crepe, technically specified rubber and rubber concentrate.

　
Standard rubber or pimpled rubber is a new category of natural rubber developed in 1960s. Previously, traditional products including smoked sheet, crepe and air-dried rubber sheet hinder the development of natural gas in terms of both grading methods and fabrication methods. For this reason, Malaysia started to implement standard rubber plan in 1965. Production of pimpled rubber is developed on the basis of physical and chemical property grading of raw rubber. Standard rubber refers to the rubber graded according to physical and chemical property indexes including mechanical impurities, plasticity retention rate, initial plasticity, nitrogen content, volatile component content, ash content and color index. Packaging of standard rubber is more advanced. Standard rubber is generally packed with polyethylene film provided with distinct marking. The package is of light weight and convenient for move. Malaysia’s package has a weight of 33.3kg, while the specified weight of China is 40kg.

　　
As the grading of standard rubber is scientific, the grading method was soon accepted by main producing countries of natural rubber and international standardization institutions who prepared grading standards of standard rubber successively. The standards are generally the same with little difference. For example, five grades are specified in the ISO2000, while four grades are specified in Chinese standard GB8081 - 87.