Nearly one-quarter of the world’s rubber comes from natural sources, making natural rubber an important agricultural product or commodity which is used in the manufacture of a wide range of products. Rubber plays a major socio-economic role in many Asian countries including Sri Lanka,
Natural rubber combines high strength with outstanding resistance to fatigue, which makes it resistant to tensile and tears. It also has excellent green strength and tack which means that it has the ability to stick to itself and to other materials making it easier to fabricate.
Moreover, Natural Rubber is the best barrier against pathogens such as the HIV virus, which is the main reason why latex is used in condoms and surgical and medical examination gloves. In addition, Natural Rubber is also used in catheters, balloons, medical tubes, elastic thread, and in some adhesives. It is also the sole raw material largely used by the global automotive industry.
Sri Lankan rubber industry has acquired historically proven core competencies in natural rubber breeding, growing, primary processing & trading. Sri Lankan Natural Rubber is exported in both raw & value-added form. The country now has a premium quality natural rubber type known as Lanakprene which is an odour free, to a certain extent light coloured, clean, rubber which is ideally suited for medical equipment and upmarket value-added products.
The main types of raw rubber produced and exported from Sri Lanka are;
In addition the country exports a considerable amount of semi processed compounded rubber, various forms of unvulcanized rubber, reclaimed rubber and wastes.
Export of crepe rubber dominated the Natural raw rubber exports in Sri Lanka while Technically specified Natural Rubber (TSR) and RSS Rubber are the other major contributors. Crepe rubber had an average export value share of 66% while RSS rubber had a share of 19% during the past five years.
Ribbed Smoked Sheet (RSS) has been a major form of raw rubber produced in Sri Lanka with the entire volume of this grade of rubber being produced by small and medium scale rubber growers with small rubber estates amounting to ten to fifty acres scattered in the rubber growing districts in Sri Lanka. Manufactured directly from the natural rubber latex which is treated and then made to coagulate, the latex sheets are then air dried or smoked in ovens and later sold to RSS Rubber Exporters in Sri Lanka who visually grade the collected sheets and pack them in bales for exportation.
Adopted mainly due to the simplicity and low cost of the processing machinery, easily adoptable processing technology, and the viability of the manufacturing process with any amount of latex, the global demand for RSS is mainly driven by the tyre industry.
Manufactured by natural rubber latex, crepe rubber is available in various grades, which is largely decided by the quality of the latex, amount of formic acid added, coagulation time, and post washing. Mostly the end result of latex crepe rubber manufacturing is rolled out in crinkled sheets, which are exported from Sri Lanka to manufacture soles for shoes and boots and other processed rubber products.
Available in varying dry rubber concentrate levels and ammonia levels, centifigured latex is the latex concentrate, manufactured by processing natural rubber latex through centrifugation. Centifigured latex suppliers in Sri Lanka provides a range of products to the global market, including;
Graded according to technical parameters such as dirt content, ash content, nitrogen content, volatile matter and properties of the rubber including Wallace Plasticity (PO) and its Plasticity Retention Index (PRI), TSR is mostly exported for the manufacturing of tyre, inner tubes and other rubber based products.