New azo cpds. with terminal carboxylic or sulphonic acid gps. - are surface-active initiators for emulsion polymerisation of olefinically unsatd. cpds.

摘要

The azo cpds. (I) have formula (1) A = alkylene, cycloalkylene, or arylene, of max. 30 C, or bisester of aliphatic, cycloaliphatic, or aromatic dicarboxylic acid of max. 30 C and aliphatic, cycloaliphatic, or aromatic diol of max. 30 C. B = alkylene, cycloalkylene, or arylene, of max. 15 C; X = -COOM or -SO3M, where M = H, alkali metal, alkaline earth metal, or NH4+; and n = 1-6. (I) are prepd. by reacting azobis(isobutyronitrile) (II) with a diol under acid conditions (Pinner reaction) then esterifying intermediate with a cyclic acid anhydride or by forming a monoester from a diol and a cyclic acid anhydride and reacting intermediate with (II). (I) may contain up to 40 wt.% oligomers. USE/ADVANTAGE - Emulsion polymerisation of olefinically unsatd. monomers (claimed), partic. butadiene, isoprene, styrene (III), alpha-methyl-(III), (meth)acrylate esters, (meth)acrylonitrile, vinyl chloride, vinyl acetate, ethylene, and/or chloroprene, partic. at 0.05-10 wt.% on monomer(s). Polymer dispersions with low electrolyte content and low tendency to foaming are obtd., (I) decompose during polymerisation without leaving N- or halogen-contg. residues, mol. fragments are incorporated in polymerisation and protect latex particles from coagulation. (0/0)