Natural rubber is made of latex. Some of the non rubber components contained in latex remain in solid natural rubber. General natural rubber contains 92% - 95% rubber hydrocarbon, while non rubber hydrocarbon accounts for 5% - 8%. Due to different preparation methods, different producing areas and even different rubber picking seasons, the proportion of these components may be different, but they are basically within the range.

Protein can promote the vulcanization of rubber and delay aging. On the other hand, protein has strong water absorption, which can cause moisture absorption and mildew of rubber and decline of insulation. Protein also has the disadvantage of increasing heat generation.

Acetone extracts are some higher fatty acids and sterols, some of which play the role of natural antioxidant and accelerator, and others can help the powder compounding agent disperse in the mixing process and soften the raw rubber.

Ash mainly contains salts such as magnesium phosphate and calcium phosphate, and a small amount of metal compounds such as copper, manganese and iron. Because these variable valence metal ions can promote rubber aging, their content should be controlled.

The moisture in the dry rubber is not more than 1% and can volatilize during processing, but when the moisture content is too much, it will not only make the raw rubber easy to mildew during storage, but also affect the rubber processing, such as the mixing agent is easy to agglomerate during mixing; It is easy to produce bubbles in the process of calendering and extrusion, and bubbles or spongy in the process of vulcanization.