PRODUCTION METHOD OF POLYPROPYLENE BASED RESIN FOAMING PARTICLE, POLYPROPYLENE BASED RESIN FOAMING PARTICLE AND POLYPROPYLENE BASED RESIN INNER FOAMING MOLDED PRODUCT

摘要

PROBLEM TO BE SOLVED: To provide an advantageous production method industrially to produce non-crosslinked polypropylene based resin foaming particles capable of attaining welding among foaming particles by low temperature steam and give a foaming particle molded product excellent in rigidity. SOLUTION: The production method of the polypropylene based resin foaming particles is characterized as follows: A surface reforming process in which while dispersing the polypropylene based resin particles in a dispersion medium in which an organic peroxide exists, the dispersive medium is held at a lower temperature than the base resin melting point of the polypropylene based resin particles and at a temperature of substantially decomposing the organic peroxide to decompose the peroxide and obtain reformed particles with a substantially non-crosslinking surface and a foaming process in which substantially non- crosslinking foaming particles are obtained by foaming the surface reforming particles using a foaming agent are included.