To suppress the production of a polymer without any introduced functional group-containing monomer by feeding a low-molecular weight functional group-containing monomer in the low-molecular weight and a high- molecular weight functional group-containing monomers and a monomer without containing a functional group, both of which are raw materials for the polymer to the reactional system in the later period of polymerization.
Among a functional group-containing monomer (A) having >50 and <1,000 molecular weight (e.g. 2-hydroxyethyl vinyl ether), in the component A, (B) a functional group-containing monomer having ≥1,000 and ≤5,000 molecular weight (e.g. a vinyl ether prepared by adding propylene oxide and/or ethylene oxide to hydroxyl group of hydroxybutyl vinyl ether) and (C) a monomer without containing a functional group (e.g. tetrafluoroethylene), the component A is fed to a polymerization reactional system in the latter period of polymerization [in the polymerization reactional stage in which the monomer in a reactor is reduced with the progress of the polymerization and the deterioration of the rate of reaction is remarkably reduced or a polymerization reactional stage in which the reduction ratio of pressure is ≤0.15 (kg/cm2)/h when the component C is a gas].
TAKAYANAGI TAKASHI
YOKOTA MIKIO
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