Sulphonated bis:phenol compounds use as drying aid for aqueous polymer dispersion, minimising discoloration

摘要

The use of bisphenol compound(s) of formula (I) or their salts as drying aids for aqueous polymer dispersions is claimed; in which >= 1 of R<1-8> = a sulphonic acid group (SO3H) and the rest = hydrogen (H); X = alkylene, carbonyl (CO), oxygen (O), sulphur (S) or imino (NR<9>); R<9> = H or alkyl. Also claimed are (a) a method for producing a polymer powder by drying an aqueous polymer dispersion with addition of (I); and (b) the polymer powder per se.