| 摘要 |
A composition comprises 70% by wt. natural fibrous material, a thermoplastic binder, and a thermosetting binder, the binders being dispersed evenly throughout the material. The moisture content is not more than 10% by wt. The fibres may be wood, e.g. as shavings or chips with sawdust or reeds, vegetable stems, or cork, or mixtures thereof. The thermoplastic binder may be e.g. an artificial resin, e.g. styrene-butadiene copolymer or cellulose derivative; or coumarone, stick shellac, bitumen or lignin. The thermosetting binder may be a phenolic, amino-formaldehyde or other artificial resin. Curing and waterproofing agents may also be present. The composition may be produced by heating the thermoplastic material to cause it to adhere to the fibrous material; a suspension of the thermoplastic and thermosetting resins may be mixed with the fibres, the mixture then being dried and ground. Articles may be produced by shaping the composition while it is heated and then cooled, some curing of the thermosetting material at the surfaces at least taking place before the thermoplastic material commences to solidify. The heating and shaping may be accomplished before the curing of the thermosetting resin is completed. |
