| 摘要 |
<p>A sound-absorbent material is made by compressing foamed synthetic plastics material so as to rupture the walls of at least some of the cells therein. Preferably a slab of polycarbodiimide foam is compressed to about 50% to 66% of its initial thickness while cold or at a temperature below 120 DEG C., and is moulded to shape while below 120 DEG C., being bonded if desired to one or more sheets of covering or strengthening or decorative fabric or felt or other facing material.</p> |
