Removing residual monomers from butadiene]-styrene] copolymer latex

摘要

A process for removing monomers from butadiene-styrene (SB) copolymers comprises passing steam into an aq. phase contg. the copolymer latex and taking off monomer-contg. vapour. The latex phase is divided into a vapour-treated vol. (A) and a non-vapour- treated vol. (B), with a ratio of (A):(B) = (1:10)-(1:40). The steam is passed into vol. (A) in a ratio of (1:3)-(1:10) (w.r.t. mass), with the temp. of (A) being 3-10 deg C above that of (B). The latex is conveyed from (A) to (B) by the steam and intermittently from (B) to (A), and the vapour is transferred from (A) to (B) together with some of the latex, the vapour being expanded into the gas space above (B) through apertures comprising 15-30% of the free surface above (A).