| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacturing a vinyl chloride polymer to be obtained using a water soluble protein as suspending agent, which can be used for producing polymer moldings being low in residual monomer concentration and nice in color tone. SOLUTION: A vinyl chloride polymer manufacturing method, characterized in that a vinyl chloride monomer or a mixture of a vinyl chloride monomer and other monomers copolymerizable with vinyl chloride monomer is subjected to suspension polymerization in an aqueous medium using a water soluble protein as a suspending agent, the obtained polymer particulates are treated by a proteolytic enzyme, the pH value of the aqueous suspension is adjusted to be 8.8-9.5, the suspension is then allowed to flow down from the upper part of a tray tower provided with perforated trays and heated by steam injected into the lower part of the tower, and deaeration is carried out at the tower top so as for the tower top pressure to be -100 to -300 mmHg.
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