| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a thermoplastic resin foam giving a foam comprising fine and uniform foamed cells. <P>SOLUTION: The method comprises the step of feeding a solid foaming material to the upstream of a heating cylinder of a twin-screw extruder 3 to melt the material by rotation driving of the screws, while injecting an inert fluid in supercritical conditions from an injection inlet 4, so as to obtain a foamed molding by extruding the resultant molten foaming material dissolved/dispersed with the inert fluid continuously from an extrusion die 20 arranged at the end of the downstream of the heating cylinder. The amount of the inert fluid injected is controlled through the viscosity of the molten foaming material, measured by a viscometer 13, so that the solubility of the inert fluid is lower than its saturated solubility. The internal pressure between the heating cylinder and the vicinity of the end of the outlet of the extrusion die 20 is controlled so that the starting position of the bubble generation lies in the vicinity of the end of the downstream of the extrusion die 20. <P>COPYRIGHT: (C)2007,JPO&INPIT</p> |
