DEVICE FOR EXPANSION OF EXPANDABLE POLYMER BEADS

摘要

An apparatus is provided wherein large low-density interlocking particles are made by expanding thermoplastic polymer beads containing a normally liquid organic blowing agent. The beads are expanded by heating to the temperature of expansion with steam in a rotating tube. Gentle agitation is provided by a combination of the tumbling action of the rotating tube and the action of the steam rising through the expanding beads. The resultant uniformly expanded particles are not crushed or shredded. The particles are suitable for use in loose-fill packaging of shock-sensitive materials.