An injection molding apparatus and method for multi-layer molding of preforms and closures has a central melt channel, an annular melt channel radially spaced from the central melt channel, and an annular ring channel surrounding the central melt channel. The central melt channel has a first portion...http://www.google.com.au/patents/US6655945?utm_source=gb-gplus-sharePatent US6655945 - Apparatus and method for multi-layer injection molding
