METHOD FOR PRODUCING MODIFIED NATURAL RUBBER

摘要

Disclosed is a method for producing modified natural rubber, comprising an epoxidation step, a removal step, and a reduction and ring-opening step. In the epoxidation step, in a latex in which a plant-derived rubbery polymer having a plurality of unsaturated double bonds in the main chain is dispersed in water serving as a dispersion medium, an organic peracid is reacted with the rubbery polymer. In this manner, by the epoxidation of a part of the unsaturated double bonds in the rubbery polymer, an epoxidated rubbery polymer is obtained. In the removal step, organic peracid-derived substances generated from the organic peracid in the epoxidation step are removed from the latex, whereby the content of the organic peracid-derived substances in the latex is reduced to 35 parts by mass or less based on 100 parts by mass of the epoxidated rubbery polymer. In the reduction and ring-opening step, under the conditions of pH 7 to 8 and in the presence of an organic acid salt, a part or the whole of the remaining unsaturated double bonds in the epoxidated rubbery polymer in the latex are reduced, and also a part or the whole of the epoxy groups in the epoxidated rubbery polymer are ring-opened.