Record material carrying a color developer composition
AssigneeThe Wiggins Teape Group Limited
InventorKenneth J. Shanton
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Abstract
A color 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, 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 300 m.sup.2 g.sup.-1. The composite may be metal-modified.
Claims8
A process for the production of record material carrying a particulate amorphous hydrated silica/hydrated alumina composite comprising:
- (a) preparing an aqueous mixture comprising dispersed, precipitated hydrated silica and an aluminum salt;
- (b) precipitating hydrated alumina from the aqueous mixture in the presence of the dispersed, precipitated hydrated silica thereby yielding an amorphous hydrated silica/hydrated alumina composite having a mean alumina content of at least 7.5% on a dry weight basis of the total weight of silica and alumina wherein the hydrated alumina is proportionally greater in the surface region of the composite and wherein the surface area of the composite is less than 300 m.sup.2 g.sup.-1 ;
- (c) applying a coating composition incorporating said composite to a substrate;
- and
- (d) drying the coated substrate to produce record material.
Dependencies are inferred from the claim text.