| 摘要 |
<p>The weaven - linked preferably paper-like polyolephine sheet or fleece, consisting of heat and pressure linked small polyolephinic fibres, which is permeable for steam or vapour and non-permeable for liquid water and dust, naturally water-resistant and featuring high tensile and shearing strength, is made being thermally weldable. The material is used for manufacturing an agent for releasing volatilizable substances e.g. phosphine, made from metal phosphides under controlled level and a complete protection of the content against running water. An excessive generation of local phosphine is prevented. The release level is controlled by the material of the sheet itself and its available surface area. The thermally weldable sheet material, particularly for upper purposes, is coated preferably by spraying dust as a coating, a thermoplastic high porous heat welded joining layer, e.g. EVA, with a much lower melting point compared to polyolephine fibres (lower for example by 30 to 80 degrees Celsius), in order to create a welded seam, before the fibres melt, thus leaving the physical properties of the polyolephine fibres and gas permeability more or less intact.</p> |
