| 摘要 |
<p>The invention relates to a composite foil or sheet, in which at least one outer cover layer, normally insoluble in water, is connected to a water-soluble at least single-layer reaction layer, which contains a dissolving intermediary for the cover layer. To achieve complete sealingtightness, at least the cover layer is constructed free from pores by the extrusion of a foil of a thermoplastic material. As a sheet the foil is constructed self-supporting or rigid. Components can have fertilizing properties and/or properties useful for water purifying. The composite foil is mainly used for packing purposes and can take the form, for instance, of a box.</p> |
