| 摘要 |
<p>A composite foil formed from at least two layers in which at least one normally water-insoluble sealing layer comprises a non-porous layer connected to at least one water soluble layer. The water-insoluble layer is soluble in a non-neutral medium and the water soluble layer is (a) water soluble or (b) water insoluble, but soluble in a non-neutral medium.</p> |
