Batch- and particle foam process
The batch- and particle foam process enables the subsequent impregnation of a polymer pellet with a propellant. The aim is to achieve a homogeneously nucleated foam with small diameters.
With the batch process, small amounts of material can be determined. This could be done either by the so-called pressure jump methode or the temperature jump method. The application of each option depends on the method used subsequently. So it makes sense to accomplish the measurements for an adjoining extrusion process with the pressure jump method, because the pressure at the nozzle during the extrusion drops down and thus leads to a foaming of the polymer.
Physical blowing agents such as CO2 are preferably used at the batch process. The material is loaded for a certain time under pressure and elevated temperature in a CO2 atmosphere. Subsequently, the material is foamed in an oil bath or an oven under defined conditions (time and temperature).
The particle foam process proceeds according to a similar principle, but the material is impregnated in an aqueous medium with the addition of a physical blowing agent. Therefore short-chain hydrocarbons, as well as polar solvents or gases can be used. The material is exposed to the propellant under pressure and temperature, so that the impregnation is completed after a few hours, depending on the diameter of the pellets. After that, the material can be foamed in water vapour or oil bath.
Both process variants are mainly suitable for amorphous polymers.
Contact: Dipl.-Ing. Daniel Raps
Phone: +49(0)921 55 74 60
Fax: +49(0)921 55 74 73