Welex Coextrusion Line

In 1994, the Polymer Processing Institute assumed the responsibility of the start-up of the seven layer coextrusion line at New Jersey Institute of Technology ( NJIT) and successfully completed the task in three months. This seven layer coextrusion pilot line, which PPI is currently managing and operating for CPPP ( Center for Plastic Packaging and Processing ), consists of two 2.5" single screw extruders and two 1.25" single screw extruders. The line is complete with one master drier and two satellite driers which are mounted on the two 2.5" extruders. Vacuum loaders, air tight transfer lines and automatic controllers are used for drying moisture sensitive materials in the main drier and feeding these materials to the satellite driers. Each of the two 2.5" extruders is equipped with two auxiliary side feeders for metering in small but precise amount of additives, screen changer for filtering out the unmelted material and Maag gear pump for metering melt to the die at constant pressure. Under normal operations, the extruder is slaved to the gear pump controller. All four extruders and side feeders are connected to a master control potentiometer which can speed up or speed down the line without changing the relative proportions of the individual components.

Picture of 34" wide sheet die

This line has been successfully used for developing a process for the production of foamed core polyolefin and polyester sheets of thickness up to 120 mil. PET, HDPE, LDPE, PS, ABS, Cellulose Acetate, PMMA, EVA and various other polymers are also extruded using this line to produce mono-layer or multi-layer sheets. These sheets are used for thermoforming.


Laboratory Scale Coextrusion Line