Process for producing polyolefin foam particles

摘要

The preparation of polyolefin foam particles of bulk density 20 - 100 g / l comprises: (A) pre-foamed particles of bulk density 120 - 400 g / l are prepared by extrusion and granulation of polyolefin containing propellent ; and (B) the particles are further foamed in one or more steps without the use of propellent, by treating with 1.5 - 8 bar steam for 5 - 120 seconds at 110 - 170 degrees C.