| 摘要 |
A mixture of ?-alumina and its precursors containing 1 to 30% water volatile at 1000.degree.C converts normally colorless dye materials such as crystal violet lactone, malachite green lactone, benzoyl leuco mathylene blue and N-phenylleukauramine to the corresponding colored dyes upon contact, and improves the results achieved with recording material consisting essentially of a fibrous web and a pigment composition secured to the fibers of the web if the mixture amounts to at least 10% of the weight of the pigment composition. Particularly strong and stable colors are produced if the fibrous web is coated with a pigment composition prepared from an aqueous dispersion of the mixture and other pigments on which a basic compound is deposited from a water-soluble zinc salt by means of hydroxyl ions. |
