摘要 |
<p>An indicating desiccant comprises a silica-based material having impregnated thereon a source of copper and a source of bromide, the source of copper being present in an amount up to 0.5 per cent by weight, calculated as Cu with respect to weight of the silica-based material, and the source of bromide being present in an amount such that the weight ration of Br to Cu is at least 5 : 1. Optionally, the indicating desiccant also comprises a dye or other coloured material.</p> |