PURPOSE: To obtain the titled resin excellent in heat stability and low in coloration due to decomposition, by chlorinating a vinyl chloride resin powder by using water, an inert gas, chlorine, etc., each of which is filtered through a specified filter medium.
CONSTITUTION: A vinyl chloride resin powder and water filtered through a filter medium, such as a sintered metal powder or a porous polymer film, which can block 10μ or larger particles, are placed in a reaction vessel and formed into an emulsion. After the O2 in the reaction vessel is purged with an inert gas filtered through said filter medium, Cl2 filtered through said filter medium is fed under pressure to the vessel. The temperature in the vessel is raised and at the same time irradiated with UV rays, if necessary, to effect chlorination. After the desired degree of chlorination is reached, the chlorination is stopped and hydrochloric acid by-product in the vessel is washed with water filtered through said filter medium. The product is dewatered by means of, e.g., a centrifuge, and dried with air filtered through said filter medium to obtain the titled resin. In this way, contamination with impurities is prevented thoroughly during the production of the titled resin.
SAEKI HIROSHI
KAKEI HIROSHI
MITO YASUHIKO
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