Polyolefin foam particles with a wide melting range for mouldings

摘要

Particulate polyolefin foam (I) is based on a phase-compatible mixt. of: (A) two or more ethylene polymers A1+A2+ .... or (B) two or more propylene polymers B1+B2+ ... of different compsn. w.r.t. type and content of monomers. The differential scanning calorimetry curve obtd. by heating 3-6 mg. of the foam particles to 220 deg C at 20 deg C/minute shows two peaks at least 17 deg C apart. Also claimed is a process for the prodn. of (I): (a) by co-extruding and granulating the polymers and foaming the granules obtd., or (b) by copolymerising the corresp. monomers in a reactor cascade, extruding and granulating the reactor blend obtd., and foaming the granules.