Removal of protein from natural rubber in pilot scale toward production of low protein rubber gloves ☆

Removal of protein from natural rubber was carried out at pilot scale in latex stage to prepare low-protein natural rubber (LPNR) and the resulting product was subsequently subjected to rubber glove production. The LPNR was prepared by the novel procedure to remove proteins from natural rubber using urea as denaturing agent together with a polar solvent, i.e. ethanol in the presence of sodium dodecyl sulfate (SDS) as a surfactant. The condition for the removal of protein was investigated in term of number of centrifugation in large scale. The residual protein, which is assessed by the amount of nitrogen in the sample, was determined by Kjeldahl method. The results showed that in the presence of ethanol, the nitrogen content decreased from 0.38 wt.% to approximately 0.07 wt.% after two times of centrifugation. The rubber glove made from the LPNR latex contains the lowest nitrogen content among various commercial rubber gloves.