| 摘要 |
1347807 Transfer receiving sheets NATIONAL CASH REGISTER CO 18 April 1972 [30 April 1971] 17821/72 Heading D2B An intermediate sheet for use in pressuresensitive manifold record forms comprises a base sheet carrying on both surfaces thereof either colourless or lightly coloured chromogenic, dye-precursor material or a colour developer for such a material. The dye-precursor material or the colour developer being in the form of isolated liquid droplets on one surface and in a dry, solid form on the other surface. Suitable, dye-precursor materials include (1) chromogenic basic dyestuffs such as Crystal Violet lactone, (2) chromogenic acidic dyestuffs such as hydroxyanthraquinones e.g. alizarine dyes, and (3) chromogenic chelating agents such as dithiooxamides and catechol derivatives such as gallic acid and esters thereof. Suitable colour developers include acidic clays and p-substituted phenol-formaldehyde novolak resins for the basic dyestuffs, Cu and Ni resinates for the dithiooxamides, Fe and V salts for the catechol derivatives, and alkyl guanidines for the chromogenic acidic dyestuffs. |
