PROCESS OF MAKING AN ALKENYL AROMATIC FOAM.

摘要

Disclosed is a process for making closed-cell, alkenyl aromatic polymer foam packing bodies or foam strands. An alkenyl aromatic polymer material is heated to form a melt polymer material. A blowing agent is incorporated into the melt polymer material at an elevated pressure to form a foamable gel. The blowing agent has 20 weight percent or more of a first blowing agent selected from the group consisting of carbon dioxide and ethane. The foamable gel is extruded through a die to form a foam strand. The foam strand is optionally pelletized to form a plurality of foam bodies. The bodies are further expanded by exposing them one or more times to heated air or steam. Preferably, the strands or bodies are allowed to age for a preselected period of time before and between subsequent expansions. The use of carbon dioxide and/or ethane as blowing agents allows the reduction or elimination of certain blowing agents dassified as volatile organic contaminants, which are currently being employed commercially in making foam bodies.