PREPARATION OF A FOAMED BODY OF A VINYL CHLORIDE-BASED RESIN COMPOSITION

摘要

The invention provides a novel method for the preparation of a foamed body of a vinyl chloride-based resin composition having a very fine and uniform cellular structure in a continuous process with outstandingly low costs. The method utilizes a binary volatilizable blowing agent composed of (i) a first volatilizable organic compound which is a halogenated or unhalogenated aliphatic hydrocarbon boiling at 90 DEG C. or below and (ii) a second volatilizable organic compound selected from halogenated or unhalogenated aromatic hydrocarbons, ethers, ketones and esters having a specified solubility parameter in consideration of the compatibility with the vinyl chloride-based resin. The process is performed preferably by use of an extruder and the resin composition heated and at least partly melted in the cylinder of the extruder is impregnated with the volatilizable blowing agent pressurized into the cylinder so as to be uniformly distributed throughout the mass of the resin composition under kneading before the resin composition is extruded out of the extruder through the die.