Process for foaming pre-expanded polyolefin particles

摘要

A process for the post-foaming of pre-expanded polyolefin granulate is claimed. The polyolefin foam particles are charged to a bulk density of 20-450 g/l at 2-25 bar and (Tm -150) to (Tm -40) degrees C for 1-48 hours with a inert gas whereby the resulting foam particles are fed to a device where a fluidised bed is produced and the particles are further expanded at (Tm -75) to (Tm +20) degrees C (where Tm is the m.pt. of the polymer).