What are the classification of natural rubber varieties?

　　Natural rubber can be divided into two categories according to the form: solid natural rubber (film and granule) and concentrated latex. Solid natural rubber accounts for the vast majority of the daily use.

　　According to different manufacturing processes and shapes, film can be divided into tobacco sheet glue, air-dried film, white wrinkle sheet, brown wrinkle sheet and so on. Tobacco sheet rubber is the most representative variety of natural rubber. It has always been a kind of rubber with a large amount and wide application. The sheet rubber is generally graded according to its shape and is divided into special grade, first grade, second grade, third grade and fourth grade. There are six grades, five grades, etc., and those that do not reach five grades are classified as external rubber.

　　Granular rubber (standard rubber) is classified according to internationally unified physical and chemical performance and indicators. These physical and chemical properties include impurity content, initial plastic value, plastic retention, nitrogen content, volatile matter content, ash content and color index. Among them, the impurity content is the dominant index, and it is divided into five grades of 5L, 5, 10, 20 and 50 depending on the amount of impurities.

　　China's futures trading market Shanghai Futures Exchange natural rubber contract delivery grade is domestic first-class standard rubber SCR5 and imported tobacco sheet adhesive RSS3, of which domestic first-class standard rubber SCR5 is also commonly known as No. 5 standard glue, the implementation of the State Bureau of Technical Supervision released The quality indicators of the implementation of the natural rubber GB/T8081 ~ 1999 version. The imported tobacco sheet adhesive RSS3 implements the "International Standard for Quality and Packaging of Natural Rubber Grades" (Green Paper) (1979 Edition) as determined by the International Rubber Quality and Packaging Conference.