CLAY MINERAL-TYPE COLOR DEVELOPER COMPOSITION FOR PRESSURE-SENSITIVE RECORDING SHEETS

摘要

A color developer composition for pressuresensitive recording sheets, comprising (1) a color developer which is derived from a clay mineral having a layer structure composed of regular tetrahedrons of silica and which shows (A) a diffraction pattern attributable to the crystals of a layer structure composed of regular tetrahedlrons of slllca when subjected to an electron diffraction analysis, but (B) substantially no diffraction pattern attributable to the crystals of said layer structure when subjected to an X-ray diffraction analysis, and which (C) contains at least silicon and magnesium and/or aluminum in addition to oxygen, and (2) 0.2 to 2 millimoles, per gram of the components (1) and (2) combined, of at least one metal compound selected from the group consisting of the oxides and hydroxides of calcium, magnesium and zinc. The composition optionally further includes a color developer composed of a dioctahedral montmorillonite clay mineral treated with an acid or a mixture of it with a naturally occurring dioctahedral montmorillonite clay mineral.