Verfahren zur Herstellung von Schaumperlen

The aim was to develop a process for the production of approximately spherical polyolefin foam particles (beads) having a coarse cell structure and a narrow cell-size distribution with the aid of dispersion foaming. This object is achieved by a process in which the reactor contents, which essentially comprise polyolefin particles, a liquid dispersion medium and optionally a volatile blowing agent, are first treated at a first temperature above the crystallite melting point Tm of the polyolefin, and are subsequently passed through a cooling device in which the dispersion is brought to a second, lower temperature, after which the polymer particles are then foamed at this temperature. The foamed particles can be converted into mouldings by known methods.