Foam molding method, foaming agent and foamed plastic

Abstract

A foam molding method, a foamed plastic formed by the method, and a foaming agent used in the foam molding method are provided. The foam molding method may include rotating a screw provided in a barrel, feeding a granular or powdered raw material and a foaming agent into the barrel, the foaming agent producing foam through a chemical reaction, melting the fed raw material and producing a gas from the foaming agent, and phase-changing the produced gas to a supercritical state and mixing the gas with the melted raw material.

What is claimed is: 
     
         1 . A foaming agent for producing a foamed plastic by producing a gas when a plastic raw material to be foam-molded is melted, wherein the foaming agent comprises:
 a granular or powdered foaming compound; and   a cell for accommodating the foaming compound, wherein the cell is decomposed during melting of the raw material.   
     
     
         2 . The foaming agent of  claim 1 , wherein the foaming compound comprises sodium bicarbonate. 
     
     
         3 . The foaming agent of  claim 1 , wherein the cell comprises at least one of LDPE, PE or PP. 
     
     
         4 . The foaming agent of  claim 1 , further comprising a catalyst for activating a reaction of the foaming compound. 
     
     
         5 . The foaming agent of  claim 4 , wherein the catalyst is citric acid.