| 摘要 |
<p>1514530 Non-woven structure; Sound absorption material MONTEDISON SpA 11 Nov 1975 [14 Nov 1974] 46452/75 Headings D1R and D2B A sound absorption material having an apparent density of 0.04 to 0.5g/cc comprises thermoplastic polymer fibrils having a surface area greater than 1m<SP>2</SP>/g held together by a binder, the weight ratio of fibrils: binder being 95:5 to 50:50. The fibril forming polymer may be polypropylene, an ethylenepropylene or ethylene-alkylacrylate copolymer, polyamide, polystyrene, polyoxymethylene, polyacrylonitrile, polyacrylate or polyvinyl chloride. It may contain kaolin, silicon, calcium sulphate, talc, calcium carbonate or titanium oxide as filler. The binder may be a thermoplastic polymer of lower melting point than the fibrils, e.g. polyethylene, polyvinyl alcohol or polyvinyl acetate, epoxy resin, unsaturated resin or an animal or vegetable glue. It may be incorporated as fibrils (ex. 1-4) 50-500 micron particles (5) or an aqueous or non aqueous solution or dispersion (6). It is mixed with the fibrils in the dry state, e.g. in a mixer or carding machine, or in the wet state, e.g. by stirring or disc refining an aqueous dispersion of polypropylene fibrils and polyethylene binder fibrils (ex. 2, 3). The dry or water dispersed mixture is introduced into containers formed of fine metal mesh heated to remove the water (if any) and soften the binder and optionally pressed. Flexible, semi rigid and rigid panels may be obtained.</p> |
