| 摘要 |
<p>The sheet is made by (a) forming an uneven surface in a mould; (b) filling the hollows with rubber or plastics material; (c) covering with cotton fabric or fibre agglomerate; (d) vulcanising the rubber or plastics material; (e) placing the top of the mould on the vulcanised composite; and (f) pressing the composite to obtain, with the tips of the mould irregularities, porous lines or areas in the vulcanised material.</p> |
