摘要 |
<p>A high solids content, aqueous, microcapsule-containing printing ink is prepared by forming microcapsules in situ in a printing ink vehicle. The microcapsules are preferably prepared by interfacial polymerization or interfacial crosslinking between a reactant, such as a polyisocyanate dissolved in an oily solution and a coreactant such as a polysalt of casein and diethylene triamine present in an aqueous solution into which the oily solution is dispensed. The aqueous solution contains water and preferrably a non-volatile diluent such as a non-reducing sugar, for example methyl glucoside. The oil-containing microcapsules contain an oil solvent and a mixture of dye precursors which upon reaction with a color developer produces an intense black image. The printing ink preferably has a 60-70% by weight solids content and may be used as a low-coat-weight CB coating for preparing carbonless copy paper.</p> |