Natural Rubber (NR) is obtained from latex extracted from rubber trees (Hevea brasiliensis) in plantations. Hevea brasiliensis, the Pará rubber tree, or, most commonly, the rubber tree, is a tree belonging to the family Euphorbiaceae. It is the most economically important member of the genus Hevea. The milky latex extracted from the tree is the primary source of natural rubber.
The latex is a sticky, milky colloid drawn off by making angular incisions into the bark of the rubber tree and collecting the fluid in containers. This process is called "tapping". The latex so collected is refined through multiple steps into rubber ready for industrial processing. Natural rubber finds varied usage in a number of applications and products, either individually or in combination with other materials.
In most of the major plantations in the world, the latex is allowed to coagulate in the collection cup or deliberately coagulated using appropriate reagent. The coagulated lumps are collected and processed into dry forms for commercial applications. In major part of its its useful forms, it has high stretch ratio and high resilience, and is extremely waterproof.
Natural Rubber (NR) is processed in the following major forms:
The two types of Sheet Rubber produced and marketed in the International market, are namely the Ribbed Smoked Sheets (RSS) and the Air Dried Sheets (ADS). Among these two types, Ribbed Smoked Sheet is the most popular and is the most available for consumption. There exist different grades of Ribbed Smoked Sheets rubber, namely RSS 1X, RSS 1, RSS 2, RSS 3, RSS 4 and RSS 5.
Natural rubber (NR) processed into Blocks adopting a newer processing technique was a notable improvement in the presentation of Dry Natural Rubber. In India, Block rubber is marketed with BIS specifications (IS4588 - 1986) and therefore, this rubber is termed as Indian Standard Natural Rubber (ISNR).