Preparation of carbon black masterbatch from natural rubber latex

Abstract

Carbon Black Masterbatch containing high carbon black content (60% by weight) was made from carbon black and a low viscosity natural rubber latex without the application of other chemical agents as well as coagulating agents. The slurry compound, after natural coagulation, was dried at 70℃ in 24h, followed by sheet shaping for next step. The Carbon Black Masterbatch was used for rubber compounding (containing 35 phr of carbon black) with natural rubber by two roll mill-mixing, and then vulcanized. Simultaneously, the reference sample was also fabricated from block natural rubber and carbon black in same compounding condition. This sample was made by directly mixing a dry natural rubber with carbon black at the same content of 35 phr of carbon black. The samples were then investigated for various characterizations for the comparison of some criteria: carbon black dispersion, vulcanization rheometer and mechanical properties (tensile strength and tear strength). The rubber sample, prepared from the masterbatch, showed the carbon black dispersion better than the ones fabricated by direct mixing method. This could be explained by the fact that carbon black was dispersed once time in Carbon Black Masterbatch. The masterbatch samples had the better properties: the curing time was shorter and the maximum torque (MH) was higher than the other sample, thank for good carbon black dispersion in the masterbatch samples. Similar results were also observed in the tensile strength and tear strength tests: samples fabricated from masterbatch possessed higher values of tensile and tear strength about 8.5% and 4.6%, respectively compared with the other sample.