Dart Container Corporation

Blaine M Kelley

Wayne J Myer

A method and apparatus for extruding a corrugation-free polystyrene foam with 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 an average cell size of less than 0.35 mm.

Apparatus for making a corrugation-free foam

A method for extruding a corrugation-free polystyrene foam with up to 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 an average cell size of less than 0.35 mm.

Process for making a corrugation-free foam

A thermoplastic foam comprises a styrenic polymer and a blowing agent consisting of 100% carbon dioxide. The thermoplastic foam has no visible corrugations and an average cell size of 0.20 mm to 0.35 mm.

Apparatus and process for making a corrugation-free foam

An apparatus for extruding a corrugation-free polystyrene foam with 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 an average cell size of less than 0.35 mm.

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Lansing, MI, United States of America

Blaine M Kelley