| 摘要 |
PURPOSE:To prevent the corrosion of the apparatus for the production of vinyl chloride polymer and to obtain a vinyl chloride polymer having improved thermal stability by adding a specific hydrotalcite to the polymerization system, thereby inactivating the hydrochloric acid generated in the production of the vinyl chloride polymer. CONSTITUTION:A vinyl chloride monomer is added to an autoclave containing 100-800 pts.wt. (based on 100 pts.wt. of the monomer) of water, 0.011 pt.wt. of a polymerization catalyst and optionally <=3 pts.wt. of a dispersing agent, a particle-size controlling agent, etc., and polymerized under stirring. In the above process, the polymerization system is incorporated with 0.001-0.05 pts.wt. (preferably 0.01-0.04 pts.wt.) of a hydrotalcite of formula (M'''' is one or more kinds of bivalent metal ion selected from Mg, Sr, Ba, etc.; M<3+> is one or more kinds of trivalent metal ion selected from Al, In, etc.; A'' is 1 to 4-valent anion; 0< x< 0.5; 0 m< 2) before, during or after the polymerization. The objective composition is composed of 100 pts.wt. of the vinyl chloride polymer and 0.001-0.05 pts.wt. of the hydrotalcite of formula. |
