Process for coinjection molding of preforms for multi-layer containers

A process for the simultaneous injection molding of a plurality of multi-layer articles in a multi-cavity injection mold comprising the steps of:

• a) supplying a metered quantity of a first material to a single hot runner manifold system defining a single path branched into a plurality of paths, each of said plurality of paths communicating with one of a plurality of injection mold cavities for passage therethrough to simultaneously supply equal quantities of said first material to each said cavity;
• b) then supplying a metered quantity of a second material contiguously with said first material to said paths to each of said plurality of cavities for passage therethrough, contiguously with said first material, to simultaneously supply equal quantities of said second material to each said cavity;
• controlling the temperature of the hot runner manifold system and said cavities to a desired temperature;
• and
• operating a valve means to sequentially supply and meter the desired contiguous quantities of said first and said second materials from respective first and second plastic material sources to said single hot runner manifold system for contiguous sequential passage of said first and second materials through said paths.