To provide a foam that has beautiful external appearances, exhibits high rigidity and has a uniform and large cell size without causing breakage of a cell wall or a void.
A master batch of a thermally expandable microcapsule is added to polypropylene and the resultant is fed to a heating barrel (1) of an injection molding machine through a hopper (3) and is mixed under pressure. Carbon dioxide in a supercritical state is injected into the heating barrel (1) through a gas injection port (2) provided in the middle of the heating barrel (1), and a resin composition is thereby caused to be impregnated with the carbon dioxide and to melt under pressure at an expansion initiation temperature of the thermally expandable microcapsule or a higher temperature. The thus-obtained foamable resin composition is injected into a cavity of a mold (7) and subsequently the movable mold (9) of the mold (7) is made to go back to a direction to enlarge the cavity thereby to decrease the pressure. Thus, the foam is obtained.
KAWAGUCHI YASUHIRO
| JP2005104998A | 2005-04-21 | |||
| JP2001079916A | 2001-03-27 | |||
| JP2001164080A | 2001-06-19 | |||
| JP2003192825A | 2003-07-09 |
Einosuke Kishimoto
Akira Watanabe
Kiyosue Yasuko
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