Apparatus and method for making foamed resin products
AssigneeThe B. F. Goodrich Company
InventorsHueng T. Kim, Sam D. Nehmey
Life of this patent
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Abstract
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.
Claims9
Method for extruding a cellular resin product comprising charging resin into an extruder disposed horizontally, conveying the resin through the extruder by means of a feed screw disposed in the extruder, melting the resin as it is conveyed through the extruder, introducing a blowing agent into the resin through a conduit in a plurality of streams along a vertical plane through said resin and extruding the mixture of the resin and the blowing agent into a zone of lower pressure whereupon the blowing agent expands to form numerous cells in the resin.
In an apparatus for extruding a cellular resin product comprising a cylinder disposed horizontally, feeding means for charging the resin into said apparatus, and extrusion screw having at least one screw flight disposed on the screw core rotatably mounted in said cylinder and longitudinally disposed therein for advacing the resin therethrough wereby the resin is progressively converted from a solid to a molten state, mixing and melting section and cooling and metering section formed by said cylinder and said extrusion screw, said cooling and metering section being disposed downstream of said mixing and melting section, the improvement comprising injection means in said apparatus for introducing a blowing agent into the resin, said injecting means extending through said cylinder and being disposed in the space between said cylinder and said core, said injection means is provided downstream of said feeding means but upstream of said mixing and melting section and comprises a conduit extending through said cylinder and disposed over said core with a small clearance therebetween with at least one port being disposed along the vertical extent of said conduit protruding into said cylinder and an unobstructed circumferential annular path within which said injection means is disposed.
Dependencies are inferred from the claim text.