| abstract |
PURPOSE: To facilitate the production of the titled block copolymer suitable as a dispersant or the like, by radical-polymerizing a radical-polymerizable monomer in the presence of a specified mercapto group-terminated polyvinyl alcohol polymer. n CONSTITUTION: A vinyl monomer based on a vinyl ester monomer (e.g., vinyl acetate) is polymerized in the presence of a thiol acid such as thiolacetic acid, and the polymer is saponified. In this manner, a mercapto group-terminated polyvinyl alcohol polymer represented by the general formula: P.SH [wherein P contains structural units of formulas I and II (wherein R 1 is H or a 1W6 C hydrocarbon and R 2 is H or a 1W20 C hydrocarbon) and the content of the unit of formula I is 100W50mol%] and having a degree of polymerization ≤3,500 is prepared. A radical-polymerizable monomer (e.g., acrylic acid) is radical-polymerized in the presence of the above produced polymer to obtain the titled block copolymer. n COPYRIGHT: (C)1984,JPO&Japio |