FOAM CONCENTRATES - ANOTHER APPROACH TO THERMOPLASTIC STRUCTURAL FOAM MOLDING.

This paper describes a new method for injection molding structural foam articles. In this method foam concentrates containing blowing agent are used. These concentrates are suited for use with both the high and low pressure foaming techniques, and are aimed specifically at the custom molder to alleviate the problems associated with dry powder blowing agents. The concentrates incorporate the chemical blowing agent in a compatible thermoplastic carrier. With a small quantity of these concentrates in stock, the custom molder can foam mold a variety of resins, with and without fillers, reinforcements, and other additives, using existing equipment and handling procedures. Details of foam concentrates available as well as of processing technology are given.