| 摘要 |
PURPOSE:To obtain a vinyl chloride resin low in the COD of waste water and improved in heat stability, by polymerizing a vinyl chloride by adding an emulsion containing finely powdered antioxidant in polymerizing the monomer by a suspension or emulsion polymerization process. CONSTITUTION:In polymerizing a vinyl chloride in an aqueous medium by a suspension or emulsion polymerization process, an emulsion prepared by dispersing finely powdered antioxidant in water with the aid of an emulsifier and/or a suspending agent is added to the reaction system and is homogeneously dispersed in the vinyl chloride resin formed. Examples of said vinyl chloride include not only vinyl chloride but also its mixture with a copolymerizable monomer. The particle diameter of the antioxidant is preferably such that it has a content of particles <=10mu of at least 99% when it is dispersed by using an emulsifier alone, and it has a content of particles <=50mu of at least 99% when it is dispersed by using both of an emulsifier and a suspending agent.
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