| 摘要 |
<p>1424682 Air laid fibrous sheets KARL KROYER ST ANNE'S Ltd 5 July 1973 [8 July 1972] 32098/72 Heading D1R An airlaid web is moistened and then consolidated by repeatedly pressing it against a heated surface whilst it is supported in continuous contact with the heated surface by a supporting metal wire mesh or a fabric to form a paper or board like product. The fibres are of wood pulp. 1 to 10% starch may be mixed with the fibres to act as binder. In the embodiment of Figure 7, distribution boxes 10, 13 lay fibres mixed with 4% starch whilst boxes 11, 12 lay fibres plus 10% starch. Vacuum boxes 14 hold the web on belt 9. Rollers 14 compact the web at 10 p.l.i. and sprays 15, 16 raise the moisture content to 30 to 50%. The web is pressed into contact with cylinder 17, heated to 230‹F, by plain unheated press rolls 18 at a pressure of 250 p.l.i. In other embodiments (Figures 1-5, 8, 9, not shown) the pressure may be 150 to 500 p.1.i., the temperature of the heated cylinder 150 to 350‹F, and some of the press rolls may be heated to 500‹F. The moisture content of the pressed sheet of Figure 7 is reduced from 15 to 10% by passage around drying cylinders 23, the sheet is sized by press 24 and further dried by cylinders 25. Alternatively the pressed sheet may be remoisted and subject to further hot pressing.</p> |
