| 摘要 |
<p>The invention relates to a soundproofing composite material and a process for preparing the same. The claimed material comprises 70...80% fir sawdust grains having a humidity of 9.3...10.4% and a density of 0.035...0.039 g/cmand 20...30% polyurethane foam, the percentage being expressed by weight. The claimed process consists in vigorously mixing the polyol and isocyanate components in a ratio of 100:70 for 5...8 s, at the room temperature, afterwards adding fir or beech sawdust grains, the resulting mixture is poured into a mould and it is maintained for 30...45 min for the reaction completion, to result in a material having a density of 0.14...0.17 g/cm, a compressive strength of 0.03...0.07 N/mm, a thermal conductivity of 0.039...0.083 W/m.K and an acoustical absorption coefficient α within the range 0.55...0.95 in the frequency range of 1000...6300 Hz.</p> |
