PROCEDURE FOR PRODUCING A RECORDING MATERIAL WHICH HAS A COMPOSITION OF HYDRATED SILICE, HYDRATED ALUMINA, AMORPHE AND IN PARTICULAR FOR COLOR DEVELOPMENT.

摘要

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 aiumina 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.