MANUFACTURING COLOUR-DEVELOPING MATERIAL COATING MONTMORILLONITE COLOUR-DEVELOPING CLAY ON SHEET MATERIAL

摘要

Potassium hydroxide or another alkaline potassium compound is used to adjust the pH of an aqueous color developing clay coating composition in the manufacture of color developing material for use in pressure-sensitive or similar copying systems. This reduces the decline in reactivity with time of such material and increases initial print intensity compared with conventional material in which the corresponding sodium compound is used for pH adjustment. Especially good results are obtained where the material being coated is a paper of high acidity such as results from rosin/alum sizing.