| 摘要 |
PURPOSE:To enable excellent color forming performance as well as excellent durability and light resistance of images to be obtained, by bringing a specified silica material and a specified magnesia material into reaction under fixed conditions to form a microcrystalline lamellar phillosilicate. CONSTITUTION:The lamellar phillosilicate comprises, on an oxide basis, SiO2 and MgO as essential constituents and Alambda2O3 and/or ZnO as optional constituents. In view of the color forming performance for the leuco coloring matter and the durability of images such as light resistance, the weight ratio of the constituents is SiO2:MgO:Alambda2O3:ZnO=45-85:10-60:0-20:0-15, particular ly, 60-80:15-50:0-5:0-10. The silica material is amorphous silica sol, silica gel or the like. The reaction is conducted by preparing aqueous slurries of the raw materials, mixing the slurries, and heating the mixture. After the reac tion is over, the microcrystals formed are agitated in the mother liquor, followed by aging or uniformizing of particle diameter. The product thus obtained is washed with water, and is dried to obtain a finished product. |
