Automating the latex fractionation process in the crepe rubber industry

Abstract

Sri Lanka is the largest manufacturer and exporter of natural Crepe rubber which is one of the purest forms of natural rubber manufactured. Crepe rubber should be manufactured in clean hygienic and controlled conditions in order to maintain its pale color and hardness in the final product. Since the inception of the Rubber industry in Sri Lanka in 1876, there hasn’t been much of a development in the manufacturing processes. We still rely on the mechanisms that the British introduced in the colonial era. The initial stage of manufacturing is called rubber fractionation, a process that is specific to crepe rubber production which is done to remove the impurities in the natural rubber latex. This process includes dry rubber content measurement, standardization (dilution to the standard) of the latex, addition of sodium bisulphite/metabisulphite and agitation for around 2 hours. These are high laborintensive tasks and when closely observed many inefficiencies and health hazards for

those who are involved could be identified. Also, the labor shortages have been a major

bottleneck in the crepe rubber manufacturing process.

The objectives of the project are increasing the efficiency and output yield by reducing

the process time and wastage of latex and also minimizing the human involvement in

the fractionation

process hence reducing the health hazards faced by the employees involved. To achieve these objectives firstly, a more efficient and reliable dry rubber content measurement method that enables high precision standardization and chemical dosing are proposed as an alternative to the current measurement using the metrolac. Then an automated solution is proposed through a working demonstration of a prototype to perform the current manual tasks of standardization, chemical dosing, agitation and determining the process end. The prototype enabled the entire fractionation process to be performed in much lesser times than the observed processes in the manufacturing facilities with higher accuracies in standardization and chemical dosing. Hence suggested improvements are proved viable to be implemented in the manufacturing facilities which will give the manufacturers a high output yield, reduce rubber wastages and enable compliance with export standards in the final crepe sheets. The ultimate goal of this study is to make a contribution to the development of the Crepe rubber industry in Sri Lanka.