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 for flow of a first material, a second portion for flow of the first material and a second material, and a flow extension connecting the first portion and the second portion. The flow extension has a flow opening in communication with the annular ring channel for flow of the second material. The apparatus and method also include a cavity for receiving flow of the first material and the second material from the central melt channel, and for receiving flow of the first material from the annular melt channel. In addition, the apparatus and method include a melt passage having a first melt portion in communication with the central melt channel, and a second melt portion in communication with the annular melt channel.