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Abstract

A process which produces a vinyl chloride resin composition for powder molding by mixing a vinyl chloride resin, a plasticizer and at least one vinyl chloride resin modifying additive in a mixer is provided, which process includes the following steps (A), (B), and (C): (A) feeding a powdery vinyl chloride resin, a plasticizer and at least one vinyl chloride resin modifying additive to a high-speed agitating mixer provided with agitating elements, a jacket, a gas-inlet port and a gas-outlet port and mixing these materials with stirring while heating them to 120.degree. C. to 130.degree. C.; (B) cooling the resulting materials in a mixer down to 70.degree. C. or lower; and (C) further adding thereto a vinyl chloride emulsion polymer and mixing the resulting materials with stirring at 70.degree. C. or lower. In the process, a gas is blown into the mixer in either both of steps (A) and (B) or all of the steps (A), (B) and (C), while mixing the contents in the mixer with stirring and blowing a gas into the mixer from the gas-inlet port and discharging the gas from the gas-outlet port, a circular motion being imparted by the agitating elements and the gas blown-in resulting in a floating motion to the contents in the mixer, and the rate of blowing the gas into the mixer being in the range of from 1 to 1,000 nl/min. per l of capacity of the mixer and the pressure of the gas blown thereinto being in the range of 0.005 to 2 kg/cm.sup.2 G. per l of capacity of the mixer.

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