| 摘要 |
The present invention relates to a method for producing a foamed article by which a foamed article having a high expansion ratio, having uniform fine cells in a high closed cell ratio and capable of being recycled, which is utilizable as heat insulating materials for construction, cushioning materials for wrapping, cushioning floats for ships, floats for sports and leisure and the like, can be obtained readily and safely using a clean inorganic gas as a foaming agent, and to a foamed article obtained by the method. That is, the present invention provides a method for producing a foamed resin article comprising a melting step of feeding a thermoplastic resin into an extruder and heating it to melt, a kneading step of mixing an inorganic gas with the thermoplastic resin in the extruder to produce a kneaded material, and a foaming step of discharging the kneaded material from a mold having a tubular channel mounted to the end of the extruder to form the foamed article, wherein extrusion molding is carried out within the range where a numeric X, which is defined by the following expression: <paragraph lvl="0"><in-line-formula>X=100P+3.5 H </in-line-formula>where a resin feeding pressure of the thermoplastic resin from the extruder to the mold is represented by H (kgf/cm2) and an expansion ratio is represented by P, and the resin feeding pressure H satisfy the following expressions simultaneously: <paragraph lvl="0"><in-line-formula>780<=X<=4000, and </in-line-formula><paragraph lvl="0"><in-line-formula>80<=H<=1000 </in-line-formula>and the like.
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