Abstract: Multi-co-injection nozzle injection molding apparatus for an injection molding machine for injection molding a multi-layer plastics article or container, comprising a plurality of co-injection nozzles, means associated with the nozzles to channel each material stream which is to form a layer of the article separately to each nozzle, means for moving the materials streams along their respective channels to their respective nozzles and means for combining in each nozzle the streams moved thereto, to form combined streams in the nozzles for injection into associated injection mold cavities. Each of the channels preferably provide substantially the same material flow stream travel path for each material stream of the same material channeled to each nozzle. Each co-injection nozzle has an axial central channel and a plurality of flow stream passageways with orifices in communication with the central channel.

Abstract: Apparatus for selectively controlling the flow of at least three melt material streams through the nozzle of a machine for injection molding multi-layer plastics articles. The nozzle has, for each stream, a flow passageway terminating at an exit orifice. Sleeve means having an internal axial material flow passageway, communicate with the central channel and with one of the flow passageways and are movable axially and/or rotationally to block and unblock at least two orifices. Each flow passageway can include material flow directing means for balancing stream flow around the passageway and its exit orifice, and a tapered portion adjacent its orifice. Preferably, the orifices are fixed. Means can pressurize melt material in a flow passageway between the flow directing means and the associate orifice so that the start of flow of the material through the orifice is substantially uniform thereabout.

Abstract: A method of simultaneously effecting the initiation, flow and termination of flow of corresponding melt streams of polymer materials from a plurality co-injection nozzles of a multi-co-injection nozzle injection molding machine to form a plurality of multi-layer injection molded plastic articles. A melt stream of polymeric material for each layer is provided and feed along an equal flow path to each nozzle using a common pressure source for each stream of a given polymeric material which is to form a layer in more than one article. A valve means effects the initiation, flow and termination of the flow of material simultaneously and identically in each nozzle.

Abstract: Valve means for use in a co-injection nozzle of a multi-polymer injection molding or blow-molding machine wherein the nozzle has an axial or cylindrical central channel, comprised of an elongated sleeve having an axial central passageway and a port in its side wall and axially-reciprocable within the nozzle central channel, and, either a solid pin within and fixed relative to the sleeve, or, more preferably, an elongated pin axially-reciprocable within the sleeve central passageway, the sleeves and pins each mounted in close tolerance slip fits to prevent any significant accumulation or passage of polymer melt material.

Abstract: A multi-coinjection nozzle injection molding machine and nozzle for co-injecting at least three streams of melt materials to form a multi-layer article. The nozzle includes at least two interfitting shells and a nozzle cap. At least one of the shells has a feed flow channel for flow of melt material which leads to an associated annular flow passageway. The shells have a symmetrical furstoconical shape and and form a fixed tapered, symmetrical, frustoconical portion of an annular passageway which terminates at a fixed, annular orifice for the flow of melt material therethrough.

Abstract: A method of forming multi-layer plastic articles by using a multi-cavity injection molding machine. A combined material stream is injected from a plurality of co-injection nozzles into associated injection cavities. Streams of polymeric materials which form the layers of the articles are directed separately into each of the nozzles and in each of the nozzles a combines stream is formed which is injected into the cavities. The individual flow of each of the material streams in the nozzle can be controlled in the nozzle.

Abstract: Injection molded and injection blow molded multi-layer substantially rigid plastic articles are provided, which, in preferred embodiments, include:at least five layer plastic articles having side and bottom walls comprised of an outside surface layer, an inside surface layer, an internal layer, and first and second intermediate layers, one on either side of the internal layer, and having the terminal end of the internal layer encapsulated by intermediate layer material, whether it be solely or primarily by first or by both first and second intermediate layer material.

Abstract: Apparatus for unit cavity and multi-cavity, multi-layer injection molding and injection blow-molding machines are provided, which in preferred embodiments, include one or more co-injection nozzle means each having a central channel, at least two passageways having associated orifices which communicate with the central channel and valve means operative in the central channel and movable to block and unblock the orifices. The valve means preferably comprise an elongated sleeve having an axial central passageway and a port in its side wall and an elongated pin axially-reciprocable within the sleeve central passageway. The sleeve and pin are mounted in close tolerance slip fit relationship to prevent significant accumulation of polymer melt material therebetween.

Abstract: A free floating runner system wherein runner means, including a runner block and its runner extension, are mounted on their axial center lines on support means, with a gap between the runner structures and surrounding structures to allow the runner structures to freely thermally expand radially and axially.A force compensation system comprised of means, preferably hydraulic, for providing a forward force to the runner structures to offset any rearward force from axial floatation of the runner means and to provide an on-line, effective pressure contact seal between the nozzle sprues and injection cavity sprues.Methods provide an on-line effective pressure contact seal between co-injection nozzle sprues and injection cavity sprues.

Abstract: A device for use with a runner block and a multi-polymer co-injection nozzle having separate rear entrance ports for separate polymer streams, in a multi-coinjection nozzle, multi-polymer injection molding machine, for receiving from the runner block a plurality of separate polymer flow streams and for redirecting them to flow axially out of the forward end of the device into the nozzle rear entrance ports. The device has inlets cut radially into its periphery, each for receiving a polymer flow stream, and has feed channels, each in communication with an inlet and having an inward portion cut toward the device's central axis, and an axial portion communicating with the inward portion, running axially forward and terminating at an exit hole in the device's forward end, the exit holes being in a spaced pattern for feeding the separate polymer flow streams in spaced relation into the nozzle rear entrance ports.

Abstract: Polymer melt material flow stream splitter devices, including runner extensions, T-splitters and Y-splitters are provided, for splitting an incoming flow stream channel for each melt material, into first and second branched flow channels of equal length which communicate with sets of first and second branched exit ports, each set in an axially aligned, spaced pattern in different peripheral surface portions of the respective splitter devices.

Abstract: Apparatus for unit cavity and multi-cavity, multi-layer injection molding and injection blow molding machines are provided, which, in preferred embodiments, include:Coinjection nozzle means, each for plural polymers, valve means for each nozzle, the valve means being adapted to move through a nozzle central channel to clear the nozzle channel of melt, a feed-block for each nozzle, polymer melt splitters, drive means for each valve means, a free floating runner system and a force compensation system to provide an effective pressure seal between the nozzles and the cavity block.