GRANULAR VINYL CHLORIDE RESIN FOR PASTE PROCESSING AND PROCESS FOR PRODUCING THE SAME

摘要

A granular vinyl chloride resin for paste processing which has a content of particles having a diameter of 10 mu m or smaller of 10 wt.% or lower, a content of particles not passing through a 149 mu m standard sieve of below 0.5 wt.%, and a bulk density of 0.45 to 0.58 g/cm<3> and which, when mixed in an amount of 100 g with 50 g of dioctyl phthalate, gives a plastic sol in which the content of particles not passing through a 62 mu m standard sieve of below 0.3 wt.%; and a process for producing the granular vinyl chloride resin for paste processing, characterized by polymerizing vinyl chloride or a mixture thereof with a copolymerizable monomer by emulsion polymerization or microsuspension polymerization to give an aqueous dispersion of a vinyl chloride polymer, spray-drying the dispersion to obtain particles, and treating the particles with an ultrasonic oscillating sieve having an opening size of 149 mu m or smaller to remove the particles remaining on the sieve.