A roll or stack of polymer sheets is prepared for saturation by interleaving the solid plastic with a porous material. It is placed into a pressure vessel where it is saturated with a gas (e.g., carbon dioxide, CO2) at sub critical pressures for a specified period of time. During saturation, the interleaf provides a gas pathway to the polymer. Once the polymer is fully saturated, it is removed from the pressure vessel and heated. Upon heating, billions of bubbles of gas are expanded in the polymer. In general, this process increases the entire roll or sheet by about 150% in width and length and about 200% in thickness.
This amount of expansion results in a dramatic decrease in density, typically about 20% density relative to the original solid, yielding three benefits:
- First and foremost, converters and manufacturers can thermoform more end-product with less source materials; therefore, lowering material cost.
- Second, converters and manufacturers can make lighter end-products from these expanded polymers than if they used a solid polymer, which is critical to certain applications, such as transportation.
- Finally, Ad-air™ technology is highly controllable and can be engineered to create a core microcellular structure with integral skin of controllable thickness, which contributes greatly toward maintaining other characteristics for the application, such as stiffness/flexibility, reflectivity, impact resistance, printability and insulation properties.
