Process for obtaining low free monomer levels in a block copolymer emulsion prepared with (reverse) iodine transfer polymerisation

摘要

A process for obtaining an aqueous emulsion comprising a block copolymer by the solution polymerisation of vinyl monomers to obtain block [B] in the presence of a) a radical precursor; and b) an iodine atom containing block [A]; where block [A] and [B] together comprise 0 to 2 wt % of methacrylic acid; where block [A] and block [B] together comprise ≧2.5 wt % of vinyl monomers bearing ionic or potentially ionic water-dispersing groups not including methacrylic acid; and performing a post polymerisation reaction on the block copolymer emulsion obtained in step II; and wherein said aqueous emulsion has a free vinyl monomer level 1000 ppm when having a solids content of ≧20 wt %.