APPARATUS FOR EXTRUSION BLOW MOLDING EQUIPMENT, BLOW MOLDING ARTICLES, PARISONS AND CONTAINERS MADE THEREFROM AND METHODS FOR FORMING THE SAME

摘要

Resin stream shut-off control apparatus for use in a multi-layer extrusion die head for continuously forming a multi-layer plastic resin parison tube suitable for blowmolding and having alternating sections X, comprised of layers formed from all the resins introduced into the die head, which sections are encaptured by one or more blow mold(s) for forming blow-molded articles, especially containers, and sections Y having portions devoid of selected one or more of the layers (which would usually be formed from the relatively more expensive of the resins) which sections Y do not comprise the final article (container) and therefore become flash or scrap. The resin stream shut-off or control apparatus includes an assembly which, in preferred usages, intermittently selectively shuts off flow of the selected one or more resin streams and thereby prevents them from forming layers in parison sections Y, and which is preferably comprised of movable means, and a die element which define a resin channel orifice and which cooperate in the die head preferably at or adjacent the orifice to prevent flow of the selected stream(s) through the orifice.