Importance

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Abstract

The coextrusion device (20) of the present invention can be used with conventional extruders (24-26) and extrusion dies (90) for forming layered products (91) from at least two materials. It includes a manifold (21) for receiving a plurality of extruded feed materials (A, B, C) and a feedblock (22) receiving the feed materials from the manifold. The feedblock includes first and second faces (43, 52), entrance ports (40, 41, 42) in the first face corresponding to the number of feed materials, channel means (50, 60, 70) passing through the feedblock between the first and second faces directing each feed material into at least one separate profile, and exit ports (51, 61, 71) in the second face corresponding to the number of channel means, defining a first profile for each feed material. An adaptor (23) is provided for receiving the first profiles from the feedblock and includes first and second faces (82, 85), an entrance port (83) in the first face receiving said first profiles, an exit port (84) in the second face corresponding to the entrance of the extrusion die and, a transition zone (86) between the entrance and exit ports wherein the first profiles become contiguous and the overall configuration of the contiguous first profiles is adapted for receipt by the extrusion die. The device can further include a reverser plate (110) and alternate feedblocks (130 ) having different exit ports (139, 140, 152, 153). Lastly, a method is provided for reducing perturbation while coextruding, utilizing a device of the present invention.

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First Claim