Cross-section of a foam sandwich injection moulding. The white outer is virgin polypropylene (PP) and the black core is foamed recycled PP (rPP). The layers are formed by first injecting the white (the colour has been used to emphasis the technology in this case) and then injecting the black with chemical foaming agent (CO2). The black rPP forms a bubble inside the white, pushing into onto the surface of the mould. In application, the surface layer would be the same colour as the core to create a high quality visual surface. This example is a cross-section through the LimbicLife ergonomic chair seat. The process and tooling were engineering and optimised by Deckerform.