| 摘要 |
PROBLEM TO BE SOLVED: To provide a recyclable polypropylene resin composition foam that is excellent in extrusion foamability, has particularly high bending strength and lightness and can be stably and continuously produced at a low cost. SOLUTION: In a method of producing the polypropylene resin foam, a foaming agent containing at least supercritical carbon dioxide is mixed into a polypropylene resin composition containing a polypropylene resin, the obtained mixture is subjected to melt-kneading using an extruder, subsequently passed through a multi-hole die to be expanded and foamed into strands, the strands are bunched to obtain the foam and the foam is heated and pressed under temperature and pressure conditions satisfying formula (2): Tm≤K≤Tm+30 and formula (3): 0.5≤S<0.95 (wherein, K is the surface temperature (°C) of the foam; Tm is the melting point (°C) of the polypropylene resin composition measured by DSC at a heating rate of 10°C/min; and S is compressibility defined by the equation: compressibility=[height (cm) of the foam after pressing]/[height (cm) of the foam before pressing]). COPYRIGHT: (C)2007,JPO&INPIT
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