With all of the advancements in resin and extrusion technology, thermoformers have plenty of options when it comes to choosing a formulation for their application. But what happens when, despite all of the choices, one singular material or color doesn't fulfill the performance or aesthetic requirements? When situations like this arise, a multi-layer coextruded product can be a simple way to achieve the material requirements. Continue reading to learn more about the coextrusion process and Impact Plastics’ multi-layer coextrusion capabilities.
The term coextrusion refers to the extrusion of multiple layers of material simultaneously. This process requires the use of two or more extruders, that melt and deliver a steady volumetric throughput of different material formulations through a single die to extrude the resin in the desired form, which in our case is sheet. This coextrusion process uses a complex die construction in which separate melt path manifolds are arranged to merge at a point close to the the die exit. The thickness of the layers can be independently controlled and are determined by the size of the individual extruders or by adjusting the speed of the extruders delivering the materials.
Coextrusion is sometimes used to apply one or more layers on top of a base material to obtain specific properties such as UV absorption, a high gloss finish, or even a different color. In other instances, when a single polymer cannot meet all of the performance requirements or specifications of an application, additional polymers or specialty materials are coextruded so that the materials are retained as separate layers in the extruded product, while simultaneously allowing the appropriate placement of materials with differing properties, such as EVOH for oxygen permeability or polyethylene for sealing.
At Impact Plastics we have multi-layer coextrusion capabilities that allow for the incorporation of several colors and materials, as well as the incorporation of high-barrier materials such as EVOH for extended shelf-life food packaging. In additon, our state-of-the-art visionX system takes quality control for multi-layer coextruded barrier formulations to the next level offering continuous measurement of each individual layer of the sheet.