| 摘要 |
<p>A colour developer for use in a pressure- or heat-sensitive record material comprises a particulate amorphous hydrated silica/hydrated alumina composite in which the hydrated silica and hydrated alumina are chemically bound and in which the mean alumina content on a dried weight basis is up to 7.5%, based on the total weight of silica and alumina. The composite may be metal-modified, e. g. with copper. </p> |
