The Dow Chemical Company

Herbert C Roehrs

Walter J Schrenk

Ralph E Ayres

Ranganath K Shastri

Mark Alan Barger

Jeffrey Nicholas Bremmer

Methods and apparatus are provided for making multilayer plastic articles. Initially, two or more streams of diverse thermoplastic materials are provided. Layers are formed from these streams and are arranged in a layered first composite stream. The first composite stream may be directly formed into a desired configuration by a molding process or may be manipulated to form a second composite stream having an increased number of layers before being formed into the desired configuration. The resulting articles are comprised of a number of discrete and substantially continuous layers.

Method and apparatus for producing multilayer plastic articles

A blow molded multilayer plastic article having a large number of layers is formed. First and second diverse thermoplastic streams are extruded into a coextrusion feedblock. In the feedblock the streams are divided into multiple streams and arranged into a first composite stream having a substantially uniform distribution of the layers. The first stream is fed into an interfacial surface generator in which the stream is manipulated to form a second composite stream having even more layers of substantially uniform thickness. This second stream is then formed into a preform such as by injection molding and this preform is blow molded. The second composite stream and preform are formed so that the layers of first and second materials lie generally parallel to a critical surface and possess substantial uniformity when blow molded.

Method for producing blow molded multilayer plastic articles

Methods and apparatus are provided for making multilayer plastic articles. Initially, two or more streams diverse thermoplastic materials are provided. Layers are foraged from these streams and are arranged in a layered first composite stream. The first composite stream may be directly formed into a desired configuration by a molding process or may be manipulated to form a second composite stream having an increased number of layers before being formed into the desired configuration. The resulting articles are comprised of a number of discrete and substantially continuous layers.

A method of making a multilayer plastic article by forming a multilayer stream of diverse thermoplastic materials and injection molding the multilayer stream directly into the article. The multilayer stream can be formed by coextrusion of the materials or by coextrusion followed by layer multiplication in one or more interfacial surface generators/static mixers. The coextruded stream, or a multiplied stream from the one or more ISG's, can also be divided into substreams and the substreams thereafter recombined prior to being injection molded so that the layers in one such substream are angularly oriented with respect to the layers in another substream.

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Beaverton, MI, United States of America

Herbert C Roehrs