Method and apparatus for coinjecting two thermoplastic materials
AssigneeOwens-Illinois, Inc.
InventorTerry C. Potter
Life of this patent
Estimating the term…
Abstract
Hot runner injection molding apparatus for coinjecting two thermoplastic materials sequentially through separate channels to form at least a two-layer sandwich material is provided. There is a valve means for instantaneously switching the flow of thermoplastic material from one channel to the other channel, the valve means preferably comprising a shuttle ball member.
Claims17
A method of coinjecting two thermoplastic materials to form a two or more layer member using a hot runner injection molding machine with two separate channels, one channel for each material, each channel having an exit end that opens into a common exit cavity having a common gate entrance to an injection mold, the method comprising of:
- A. heating the thermoplastic materials in the two channels;
- B. injecting material from the first channel through the common gate into the injection mold;
- C. simultaneously forcing a valve member to seat itself in the exit end of the second channel to prevent intermixing of the two materials;
- D. sequentially injecting material from the second channel through its exit end into the common exit cavity and into the common gate entrance;
- E. simultaneously stopping the flow of material into the common exit cavity by forcing the valve member into the exit end of the first channel to seat itself therein;
- and
- F. simultaneously cleaning the first material from the exit cavity and the gate entrance by forcing the valve member and the first material into the exit end of the first channel.
A hot runner injection molding apparatus for coinjecting two thermoplastic materials sequentially through separate channels to form at least a two-layer sandwich material, each channel being independently heated and each channel having an exit end in communication with a common exit cavity with a common gate entrance to a forming mold, there being valve means for instantaneously switching flow of thermoplastic material from one channel to the other channel without intermixing materials from the two channels, the valve means being disposed within the common exit cavity between the exit ends of the channels, the valve means comprising a shuttle member that removes residual material from the common gate entrance and seats in the exit end of one channel as material flows through the exit end of the other channel into the common exit cavity and through the common gate whereby the materials are sequentially injected into the mold.
Dependencies are inferred from the claim text.