| abstract |
Record material comprising paper sheet material coated with liquid-containing microcapsules wherein the liquid contents comprise isopropylbiphenyl and no halogenated hydrocarbon liquid. Said liquid is associated on the record material with at least two color-producing reactants, at least one of which is soluble in said liquid. The encapsulated liquid is associated with the reactants by either being in close proximity to both reactants or by having one of the reactants dissolved therein and being in close proximity to the other. Of the color-producing reactants, one is a chromogenic dye-precursor and one is a coreactant material capable of developing the color of the chromogenic dyeprecursor when the two reactants are brought into reaction contact by rupture of the capsule walls that contain said liquid. |