Research on the Bead Foaming Technology of Polypropylene
With polypropylene resin as the foaming raw material,carbon dioxide(CO2)as the foaming agent,water as the dispersion and heat conduction agent,the preparation process of polypropylene foam beads was explored in a high-pressure reactor.The effects of foaming pressure and foaming temperature on the foaming behaviors of polypropylene were studied,and the process conditions for preparing polypropylene foam beads with different foaming ratios were obtained.The results show that in a certain temperature range,the foaming ratio of polypropylene beads increases with the increase of temperature,but the excessive temperature leads to the adhesion of foam beads.The increase of foaming pressure can also increase the foaming ratio of beads,increase the nucleation density of cells,and decrease the cell size.