Foamable styrenic polymer gel having a carbon dioxide blowing agent and a process for making a foam structure therefrom

摘要

Disclosed is a foamable styrenic polymer gel capable of forming a closed-cell foam structure, comprising: a) a flowable melt of a styrenic polymer material comprising greater than 50 percent by weight styrenic monomeric units and about 0.1 to about 40 percent by weight of oxygen- containing monomeric units based upon the total weight of the styrenic polymer material; and b) a blowing agent comprising about 5 weight percent or more carbon dioxide based upon the total weight of the blowing agent. Further disclosed is a process for making the foam structure. The oxygen-containing comonomer content in the styrenic polymer material enables process operating pressures to be significantly reduced when using carbon dioxide as a blowing agent compared to a styrenic polymer material without comonomer content. The foam structure formed is of low density and of good quality.