| 摘要 |
<p>1529363 Building panel DURISOL AG FUR LEICHTBAUSTOFFE 15 Oct 1975 [30 Oct 1974] 42205/75 Heading C3N [Also in Divisions D1 and B5] A building panel made from organic fibres, a binder and an inorganic material which is absorbed by the organic fibres to the extent of at least 2% by weight of the fibres and hence "mineralizes" them, comprises at least three gradually merging layers, at least one of which has longer fibres and a lower weight/unit volume of binder than at least one other layer. The specified binder is cement the fibres are 1 to 25 mm. long wood fibres and the inorganic material is aluminium sulphate. Preferably short fibres of length 2 to 8 mm. comprise a first fraction and fibres of length 8 to 20 mm. at least 80% of which are not longer than 12 mm. comprise a second fraction the weight ratio of the first to the second fraction being between 1 : 2 and 1 : 3. Moist Portland cement is added to each fraction, the first fraction having a larger proportion of cement to fibres than the second fraction. Mica and/or perlite may be added to the mixture to increase the fire resistance of the panel. In one embodiment a three layer board is formed by spraying the first fraction from a first spray head followed by the second fraction from a second spray head and further first fraction from a third spray head, so that the layers move into each other. The board is compressed whilst the cement sets. The density of each outer layer is at least 1-3 times that of the inner layer. In a second embodiment, Fig. 10, the first fraction forms the outermost and innermost layers of a 5 layer structure. Reinforcement, lamination.-Reinforcements 6, 7 comprising glass fibres, glass filaments or a plastic or metal net may be inserted after the first and fourth layers have been deposited. Aluminium or plastics sheets, 8, 9 may be bonded to the board in the press.</p> |
