APPARATUS AND PROCESS FOR MAKING A CORRUGATION-FREE FOAM

摘要

A method and apparatus for extruding a corrugation-free polystyrene foam wi th 100% carbon dioxide as the blowing agent by extruding the extrudate through an annular die opening so that it contacts a choke ring inner surface. A foam made with the apparatus according to the invention will have no visible corrugations and a n average cell size of less than 0.35 mm.