| 摘要 |
PROBLEM TO BE SOLVED: To manufacture a polypropylene resin foam having high foaming magnification, high closed cell rate and beautiful appearance through simple steps. SOLUTION: This method for manufacturing a foam made of a polypropylene resin comprises the steps of (a) supplying a mixture of a polypropylene resin, an aromatic vinyl monomer and a radical polymerization initiator to a first stage biaxial screw type extruder of a tandem type, (b) melting and kneading the mixture by the first stage biaxial screw type extruder, (c1) press injecting a foaming agent to the melted and kneaded material in the extruder, continuously feeding the material press injected with the agent to a second stage uniaxial screw tape extruder, (d) cooling the melted and kneaded material to the temperature suitable for foaming in the second stage extruder, and (e) passing the kneaded material through a die and extruding it in a low-pressure atmosphere. |
