Sheet rubber, also known as Ribbed Smoked Sheet (RSS), is a significant form of natural rubber used commercially. It is produced from fresh latex harvested from rubber trees (Hevea brasiliensis) through a series of processing steps:
- Latex Collection: Collected by tapping the bark of the rubber tree to allow the latex to flow out.
- Preliminary Treatment: The collected latex is diluted, filtered to remove impurities, and an acidic substance is added to initiate coagulation.
- Sheet Formation: The coagulated rubber is rolled and pressed into thin sheets.
- Smoking and Drying: These sheets are then smoked and dried using wood smoke. This process not only dries the rubber but also imparts some anti-aging and anti-corrosion properties due to the creosote present in the smoke.
Characteristics of RSS include a ribbed surface pattern, an amber color, semi-transparency, and a faint smoky odor. Its specific gravity usually ranges between 0.90 and 0.93, with a rubber hydrocarbon content around 92.8%, and minimal non-rubber components, indicating a high quality. RSS is classified into various grades based on criteria such as appearance (bubbles, impurities, spots), chemical composition (moisture, ash content, soluble matter, acetone extract, protein), and physical-mechanical properties (tensile strength, elongation, aging coefficient), adhering to international rubber grading standards. Grades include Super, Grade 1 (standard), Grade 2 (good), Grade 3 (ordinary), Grade 4 (low grade), Grade 5 (inferior), and Grade 6 (substandard).
Sheet rubber, particularly RSS, serves as a primary raw material for tire manufacturing and a wide array of other rubber products, valued for its comprehensive performance attributes and versatility in the rubber industry.
