| 摘要 |
A colour developer for use in a pressure- or heatsensitive record material comprises a particulate amorphous hydrated silica/hydrated alumina composite in which the hydrated silica and hydrated alumina are chemically bound, in which hydrated silica predominates, in which the mean alumina content on a dried weight basis is at least 7.5%, based on the total weight of silica and alumina, and in which the surface area is below 300m<2>g<-><1>. The composite may be metal-modified. |
