| 摘要 |
<p>A moulded body of cellulosic vegetable fibre material comprises mainly pentosanfree furfural-contg. fibres, and is esp. in the form of a fibrous plate or fibrous drip plate contg. =50% wood chip. The furfural is pref. present in insoluble highly polymerised form. The body is moulded pref. from a fibre slurry treated with (in)organic acid to give a pH 2.0-4.5 pref. 3.0-4.0 and then compressed at 100-220 degrees C. Pref. an aldehyde hardener or its precursor is added in amt. 0.2-5 esp. 0.5-1% w.r.t. furfural content. Pref. also =100% esp. 50% of the hardeners comprise furfuramide. Pref. the slurry is pre-shaped prior to final moulding by heating to =100 degrees C under light pressure and then wetting and compressing at high pressure and 180-220 degrees C to polymerise the furfural. The organic or inorganic acid and the aldehyde hardener are added to the wettened liquid prior to final compression. The hardener is esp. formaldehyde or a polymerisation prod. of HCHO, or hexamethylenetetramine. Previous wet and semi-dry processes required use of large amts. of synthetic resin binders and use of water-proofing agents. Also only about half the furfural was usuable, the rest causing environmental pollution problems in waste. The structural integrity, strength and water-resistance of the mouldings are improved. Wet, semi-dry or dry process may be used. The polymerised furfural acts both as binder and water-proofing agent.</p> |
