| 摘要 |
PROBLEM TO BE SOLVED: To provide a foamed material composed of a polypropylene resin composition containing a polypropylene resin as a main component and having low density, high closed cell ratio and excellent heat-insulation performance. SOLUTION: The heat-insulating foamed material composed mainly of a polypropylene resin has high heat-insulation performance by controlling the density, closed cell ratio and foam diameter without depending upon the gas generated from a foaming agent. Concretely, the heat-insulating polypropylene resin material contains >=50 wt.% polypropylene resin and has a density of 50-10 kg/m3, a closed cell ratio of >=50%, an average foam diameter of <=1.5 mm and a thermal conductivity of <=0.040 W/m.K (0.034 kcal/m.h. deg.C) at an average temperature of 20 deg.C.
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