GrafCoat-2: Graphene based extrusion coatings for paperboard

Purpose and goal:

The project´s aim was to further evaluate the thermoplastic graphene biopolymer material developed in GrafCoat-1. The motivation is a sustainable material for extrusion coating of paperboard. In GrafCoat-2 the focus has been on extrudability and lamination of pressed films onto paperboard.

After some optimization, the project produced materials and a process that enabled extrusion. Pressed films laminated very well to paperboard and had good sealability. This, in combination with the films´ good barrier properties, makes the concept interesting for further development Expected results and effects:

Initially, it was difficult to obtain enough material, but the process has and is being optimized for larger production. It was also difficult to extrude the material. It solidified quickly and was difficult to get out of the extruder.

Mounting a heat source close to the outlet solved the problem. The extruded material could be pressed into thin films and several pieces of material could be pressed together into larger films. But, the fusion of the material was not perfect and thus no fused films were evaluated. Good adhesion to paperboard and promising barrier properties were demonstrated

Approach and implementation:

2D fab delivered optimized qualities of graphene. RISE stabilized the graphene, mixed it with theromoplastic starch, perform extrusion trials and pressed the material into thin films. Holmen and RISE then evaluated the properties of the films: free standing films and laminated onto paperboard