The B. F. Goodrich Company

Hueng T Kim

Sam D Nehmey

Cellular thermoplastic resin is made by the method and extrusion apparatus that is characterized by a compaction section where the resin is densified, a choke section where a barrier of the densified resin is formed that is substantially impervious to a gaseous blowing agent, and a mixing section where the particulate resin is mixed with a blowing agent and then melted before being extruded into a zone of lower pressure whereby the blowing agent expands to form the cellular product. By mixing the blowing agent with a solid rather than a molten resin, the resulting mixture can be melted at a substantially lower temperature.

Method and apparatus for extruding a cellular product

Extrusion apparatus and method for making a cellular resin product are characterized by a conduit that extends into the extruder whereby a blowing agent is injected therethrough into the resin through a plurality of ports provided in the conduit in order to disperse the blowing agent more uniformly through the resin before it is extruded through a die into a zone of lower pressure whereupon the blowing agent expands to form numerous cells within the resin structure.

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Avon Lake, OH, United States of America

Hueng T Kim