Co-injection nozzle for an injection moulding device for producing multi-layered injection-moulded products

A co-injection nozzle for an injection moulding device for the production of multilayer injection moulded products from a multilayer injection, the nozzle comprising:

• a nozzle body forming a body central bore;
• a melt distribution insert (hereinafter “insert”):
• (a) forming an insert central bore,
• (b) in mutual contact with the nozzle body along an upstream portion of an axial length of the insert,
• (c) defining a longitudinal axis having an upstream end and a downstream end at an opposite end of the longitudinal axis relative to the upstream end, and
• (d) having a circular cylinder-shaped end profile located at the downstream end;
• a circular shaped lower separating sleeve positioned to surround the insert along the longitudinal axis of the insert at the downstream end;
• a nozzle orifice positioned proximate the downstream end of the insert and from which the multilayer injection is output from the co-injection nozzle;
• a first melt supply channel for a first melt;
• a second melt supply channel for a second melt;
• an axially movable valve needle accommodated in the insert central bore to open and close the nozzle orifice;
• an annular inner melt channel which is formed between the insert central bore and the valve needle and being in fluid communication with the first melt supply channel;
• an annular middle melt channel which is in fluid communication with the second melt supply channel and which extends about the annular inner melt channel between the circular shaped lower separating sleeve and an exterior surface of the insert along the longitudinal axis of the insert at the downstream end of the insert;
• an annular outer melt channel which is in fluid communication with the first melt supply channel and which extends about the annular middle melt channel at the downstream end of the insert;
• the inner, middle and outer melt channels converging fluidically in the region of the nozzle orifice to form a concentrically layered melt stream;
• and
• at least one distribution channel for the first melt and at least one distribution channel for the second melt being formed in the surface of the circular cylinder-shaped end profile of the insert;
• wherein the separating sleeve includes an inner surface of which forms part of the annular middle melt channel and an outer surface of which forms part of the annular outer melt channel.

A co-injection nozzle for an injection moulding device for the production of multilayer injection moulded products from a multilayer injection, the nozzle comprising:

• a nozzle body forming a body central bore;
• a melt distribution insert (hereinafter “insert”):
• (a) forming an insert central bore,
• (b) in mutual contact with the nozzle body along an upstream portion of an axial length of the insert,
• (c) defining a longitudinal axis having an upstream end and a downstream end at an opposite end of the longitudinal axis relative to the upstream end, and
• (d) having a circular cylinder-shaped end profile located at the downstream end;
• a circular shaped lower separating sleeve positioned to surround the insert along the longitudinal axis of the insert at the downstream end;
• a nozzle orifice positioned proximate the downstream end of the insert and from which the multilayer injection is output from the co-injection nozzle;
• a first melt supply channel for a first melt;
• a second melt supply channel for a second melt;
• an axially movable valve needle accommodated in the insert central bore to open and close the nozzle orifice;
• an annular inner melt channel which is formed between the insert central bore and the valve needle and being in fluid communication with the first melt supply channel;
• an annular middle melt channel which is in fluid communication with the second melt supply channel and which extends about the annular inner melt channel between the circular shaped lower separating sleeve and an exterior surface of the insert along the longitudinal axis of the insert at the downstream end of the insert;
• an annular outer melt channel which is in fluid communication with the first melt supply channel and which extends about the annular middle melt channel at the downstream end of the insert;
• the inner, middle and outer melt channels converging fluidically in the region of the nozzle orifice to form a concentrically layered melt stream;
• and
• at least one distribution channel for the first melt and at least one distribution channel for the second melt being formed in the surface of the circular cylinder-shaped end profile of the insert;
• wherein the at least one distribution channel for the first melt is connected downstream with the annular outer melt channel via a bore in the separating sleeve.